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Treatment as Prevention. A last short postscript

I have written several posts dealing with “Treatment as Prevention”  referring to proposals that the epidemic could be controlled by testing and treating all infected people.   However, as this phrase is also used in a different, although related context, I am adding this last postscript.

Thus,  “treatment as prevention” has a context that concerns populations and considers a strategy to  control and even end the epidemic.    The same phrase  also has a context that deals with prevention of infection at an individual level, and focuses on transmission risks  between two people.

The latter context was brought to attention in 2008 by the Swiss Federal Commission on HIV/AIDS.  Their publication essentially states that, under certain conditions,  with effective antiviral treatment achieving an undetectable viral load, the risk of sexual transmission without condom use is not greater than that with the use of condoms.

Among the conditions stipulated is that there is no sexually transmitted infection, and that the viral load has been undetectable for at least six months.

http://www.aids.ch/e/fragen/pdf/swissguidelinesART.pdf

Now a German voluntary organization, Deutsche AIDS-Hilfe, has added support – with some modifications to the Swiss statement.

http://www.aidshilfe.de/media/de/0904_DAH-Papier_HIV-Therapie_und_Praevention_Englisch.pdf

There was a huge controversy when the Swiss recommendations were first made public in 2008.  Their conclusions were rejected  by groups  in the US,  even by those who promoted the application of the same principle – the reduction in infectivity conferred by treatment – as a means of controlling the epidemic.

I was – and am – absolutely supportive of the Swiss recommendations as applied to individuals.  Here is an excerpt from a letter I wrote when the Swiss document was published:

“The report is absolutely reasonable. There are caveats and cautions in it, and since I can see no reasonable objection to them, we have to look elsewhere to try and understand why the report has provoked such a furious response. I know it is a bit pedantic and pretentious but I’m going to add a quotation that is over 100 years old that recognizes that scientists can be as irrational as anyone else (especially about sex), here it is:

In Man Adapting, Rene Dubos notes that:

“The presuppositions on which medicine operates are thus conditioned by the general philosophy of the social group as a whole” and adds the words of Oliver Wendell Holmes in 1860:

“The truth is that medicine, professedly founded on observation, is as sensitive to outside influences, political, religious, philosophical, imaginative, as is the barometer to the changes in atmospheric density”10
I would bet that some who have commented have not even read the cautious Swiss text, and have allowed their prejudices and squeamishness about sex in general to surface at the very mention of sex without condoms.

The Swiss authors do deserve some recognition for their courage. There are circumstances in which it is not irresponsible to have sex without condoms. And even for those for whom these circumstances do not apply, the knowledge of the possibility of sex without condoms will be an encouragement, in at least two ways.

Firstly, to continue using condoms when this is necessary, and then as a support with treatment adherence and monitoring.

I say these things as someone who had something to do with the original introduction of condom use for AIDS prevention in 1983, – briefly described here:

http://aidsperspective.net/articles/Callen-Berk_collaboration4.pdf

and until now thought – as probably most did, that condom use  would be forever.

Knowing that this is not necessarily so is a tremendous encouragement and I believe this thought alone will help our prevention efforts”.

I have continued to encourage the use of condoms, but I do welcome the Swiss document for pointing out, with appropriate documentation and caution, that there are circumstances when it is not irresponsible to dispense with them.

This also means that there are circumstances when conception is possible. There are also implications in situations where there are laws that criminalize sexual contact with HIV infected people under certain circumstances.

A large part of the irrational responses to the proposal are I believe based on a disparaging attitude towards sex.

For many, the use of condoms is a barrier to intimacy.  The knowledge that if certain circumstances can be met, an infected person is not endangering their sexual partner by dispensing with condoms is in fact a life affirming celebration of sex, one of life’s joys.

Admittedly, dispensing with condoms will not be possible for most individuals.  It is probably most relevant to serodiscordant couples in a stable relationship – that is where only one of the partners is HIV infected.

But knowing that this might be achieved could be a great support to most HIV infected people  who must continue to use condoms   It will also be a greater incentive to remain adherent to one’s treatment regimen.

Of course the diminished infectivity of effectively treated individuals is the basis for the proposals to use treatment of all infected people as a means of controlling the epidemic.

This is a very different situation, most importantly because it will involve treating people who do not need to be treated for their own personal benefit. These healthier people will derive no benefit from the medications and only be exposed to their side effects.  I have written about this in previous posts on treatment as prevention.

Except for the relatively uncommon situations outlined in the Swiss document, and more cautiously and explicitly, in the German document, the consistent use of condoms remains one of the most important measures we have to prevent infection.

Early concerns about confidentiality in AIDS, and what Jim Monroe had to do with this.

April 23, 2009 1 comment

From time to time I will write about some extraordinary people I have worked with. The first of these is Jim Monroe.

Jim worked for the Centers for Disease Control (CDC).  He worked to improve the health of all, but it is people with AIDS who probably derived the greatest benefit from his efforts.

Those who do the most to help others often remain completely unnoticed. Maybe their commitment leaves no room for seeking personal attention; maybe they don’t care about recognition, or actively shun it.

Jim Monroe personally helped many individuals who were in great need.  He was also the person who was probably responsible for first bringing attention to the issue of confidentiality in AIDS in the earliest years of the epidemic.

He most certainly did not care about personal recognition.  Apart from a few friends and colleagues and those who directly benefited from his efforts, he remains largely unknown.

I first met Jim in the late 1970s. I was at that time working for the New York City Health Department, concerned with sexually transmitted infections.  Jim worked in the same field, but for the CDC.  He was based in New York City.  Our places of work were in close proximity and we met through our common interest in the control of sexually transmitted infections.

Jim is probably the person who was responsible for the early attention given to confidentiality in connection with AIDS

Confidentiality in matters of health is of the greatest importance; it is also complex, with some special concerns in connection with sexually transmitted infections.

We have an obvious obligation to respect the trust placed in us by those who seek our care. But there are different and strongly held views on the tensions that can exist between individual rights to privacy and the protection of sexual partners, as well as society at large.

But the context in which Jim brought attention to confidentiality was the concern to protect individuals suffering from this new, untreatable, and as yet unnamed disease.   From the very start, affected individuals frequently had to contend not only with this frightening illness but with irrational and cruel discriminatory acts against them.

Not only was the disease itself associated with stigmatization, particularly in the early years, there was yet another issue requiring attention to confidentiality.  Sexual orientation was revealed with a diagnosis when the disease was thought to be confined to gay men. As other groups of individuals were identified, perhaps only those who acquired the disease from blood products were relatively free from the threat of discriminatory practices that were all too frequently directed against gay men and IV drug users.

Those were the days when HIV infected people in hospitals had to retrieve their meals which had been left outside their doors;  when medical personnel would refuse to care for infected people; when some children were not allowed to be in contact with those known to be infected, and infected children sometimes not allowed to attend school.  Thankfully in the US today children are protected.

http://www.ed.gov/about/offices/list/ocr/docs/hq53e9.html

But despite advances, AIDS is still a disease associated with stigmatization, not only in developing countries but also in the US and other developed nations.

I will describe how Jim started a response intended to assure that those affected by this new disease would be protected by measures to maintain their confidentiality.

A few introductory words are needed.

I started my own research into this new disease in 1981, and received tremendous support from an old colleague in the interferon field, Dr Mathilde Krim.

In 1983, my lawyer, Frank Hoffey with Graham Berry prepared the papers and incorporated the AIDS Medical Foundation (AMF), initially to raise funds to support my research.  Apart from Mathilde’s personal support our work was not funded.  AMF soon broadened its mission to support the work of others as well.

Fundraising during the first year was very difficult and the foundation really owes its survival to the efforts of Dr Krim, who was the chairman of the board.

Concern with confidentiality started with an anxious call from Jim in 1982.  The reason for his extreme agitation was that he knew that a study was to be undertaken on this new disease in the Health Department clinics for sexually transmitted infections. In particular, the clinic on 28th street was known to be the site where large numbers gay men were treated for sexually transmitted infections.   The study would be concerned with people who had “reversed T cell subset ratios”.  A reversal of the normal CD4: CD8 ratio was how we recognized AIDS before the name was coined.

What concerned Jim was that no provision had been made to protect the confidentiality of the study participants. Their names were to be recorded.  I cannot recall if the proposed study was a CDC study or one originating with the Health Department.

Jim told me that the study was to be submitted for review by New York  City’s Institutional Review Board (IRB) although it was not called an IRB.  I suppose he must have had little confidence that the IRB, which is a body regulated by the FDA and intended to protect human research subjects, would address the confidentiality issue. In view of what transpired he was probably correct.

I also don’t know what he expected I could do. Maybe he just wanted to share his frustration with a person who shared his concerns.

In the event, this call was to actually result in something that would have lasting effects.   I spoke about this to Mathilde, who I knew also shared these concerns about protecting confidentiality.

She immediately said that she knew who could effectively deal with this problem.  Mathilde was associated with and had provided support to the Hastings Center, which was concerned with bioethics, and introduced me to Carol Levine and Ron Bayer.  I conveyed Jim’s concern about the proposed study  and the result was that I attended a meeting at the Health Department with Carol or Ron, or maybe both were there, as well as a lawyer from Lambda Legal Defense Fund, whose name I think was Chris Collins.

As a consequence, because of a lack of provision for confidentiality protection, the study was tabled.

Jim Monroe’s concern to protect individuals with AIDS started this train of events.

It is hardly surprising that not much attention had been given to the issue of confidentiality in 1982. The disease was after all new, and we were just learning of the extremely hostile and irrational responses directed at those who were affected.

Carol and Ron’s interest did not stop.  I think it was Ron Bayer who proposed that a meeting be held on the issue of confidentiality.  This meeting in fact did occur and resulted in the publication of guidelines for confidentiality in research on AIDS.

Lloyd Schloen had worked at Memorial Sloan Kettering Cancer Center as a fund raiser.  Mathilde had introduced us and we had become friends.

Lloyd then became an official at the Charles A. Dana Foundation, and we talked about confidentiality protection.  It is through his efforts that the meeting on confidentiality was funded.

The meeting proceedings were published in the Hastings Center’s own publication, IRB.

http://www.jstor.org/pss/3564421

I believe my memory is correct in recalling that an established medical journal declined to publish the guidelines.

I was editor of a journal devoted to AIDS called AIDS Research and had absolutely no hesitation in publishing the guidelines myself. Some pages are reproduced here.

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Later, the CDC was to publish its own set of guidelines.

The Hastings Center guidelines were not the only publication on confidentiality that preceded the CDC’s recommendations.

As part of my research effort I had become associated with David Purtilo, Chairman of the Pathology and Microbiology Departments at the University of Nebraska’s medical school in Omaha. The reason for this was that David was an expert on the Epstein Barr virus, and I believed that this common herpes virus can play a significant role in the pathogenesis of HIV disease[i].

David’s wife, Ruth Purtilo is a bioethicist. She clearly saw how important confidentiality protection was in research on AIDS. She obtained the perspective of Michael Callen, a patient of mine who was HIV infected. Together we wrote a paper on this issue in 1983.

Confidentiality, informed consent and untoward social consequences in research on a new killer disease (AIDS).

Clinical research, {Clin-Res}, Oct 1983, vol. 31, no. 4, p. 464-72, ISSN: 0009-9279.

Purtilo-R, Sonnabend-J, Purtilo-D-T.[ii]

Unfortunate developments today have made the need for respecting confidentiality as important as was the case when the epidemic began.  Differently worded legislation now exists where criminal law is applied to people who transmit HIV to others, or even who expose others to the risk of transmission. There is absolutely no evidence that such criminalization prevents the spread of this disease.  The following link will provide useful sources of information.

http://data.unaids.org/pub/BaseDocument/2008/20080731_jc1513_policy_criminalization_en.pdf

These laws only increase stigmatization.  The introduction of such legislation in many countries is an important additional reason why concerns about confidentiality protection remain vitally important.

Jim Monroe returned to work at the CDC in Atlanta.  Although he was assigned to work in another field, his interest in AIDS remained. He was the kindest of individuals, personally helping people with AIDS, as well as others in difficulty.

The very last project on which we worked was cut short by his death.

Even then, in the late 1990s, the problem of when it is best to start antiviral therapy was of concern – indeed it had been of concern ever since the introduction of AZT.  We then believed – as many still do today, that the question is most reliably approached by a randomized prospective study.  Most certainly not by the opinions and recommendations of experts, not all of whom could properly be considered qualified to hold that rank.

We thought that those entities that pay for the drugs might be the appropriate sponsors of prospective clinical trials.  They have a clear interest in knowing if it is beneficial or not to start treatment early rather than to defer it, or whether it makes no difference.

It is in their interests; if early treatment provides no benefit – (at least one large retrospective study suggests that there is no benefit to starting treatment above a CD4 count of 400) then paying for an early start to treatment would be pointless. On the other hand if early treatment produced some benefit then the cost would certainly be justified.

Among the entities covering the cost of drugs are government agencies such as Medicare and the VA.   The VA has a history of undertaking studies.  There are also the private insurance companies.

Jim together with a Public health expert at Emory University was attempting to present a proposal to the medical directors of private insurance companies. We had the support of an eminent statistician who had also been involved with me on an earlier unsuccessful attempt to set up a study to compare early and deferred treatment with AZT.

This attempt was brought to an end by Jim’s sudden death, as well as by the illness of another one of us working on the proposal.

One Friday afternoon while seeing patients in a clinic in New York City,  I received a call from a friend of Jim’s in Atlanta. She told me that Jim was severely ill in Chicago. He had collapsed a few days earlier.  On Saturday I travelled to Chicago and found Jim unconscious in a hospital. He was not to recover.

None of us knew that Jim had been ill. He kept this a secret while continuing to work  to improve the health of all people, both in his assigned work but also through his initiatives on behalf of people with AIDS.

Jim’s final project, cut short by his death, is still absolutely relevant.

Some recent suggestions, based on the flimsiest of evidence propose that treatment with antivirals should be started even earlier than the current recommendations.  There are well meaning physicians today who already buy into this nonsense, who state that they would treat all infected people, irrespective of CD4 count. Or they would raise the CD4 threshold above 350, which is the currently recommended level at which to initiate treatment, even in the absence of reliable evidence that their patients will benefit.

It cannot be reliably known from any evidence we  have at present whether such prolonged exposure to  antiviral drugs will increase or decrease survival or be without effect in this respect – of course except for cost.

We do need to really know when it is best to start treatment.  Prospective randomized studies can provide an answer to the question if, on average it is better to start treatment early or to defer it.

Hopefully others will take on Jim’s last project and write a proposal to some of the entities who pay for the drugs, to sponsor  prospective studies,  the only reliable way to answer this question.

Are they wasting money? Are they getting their money’s worth?

Surely the payors, will want to know.


[i] I still believe this to be true,  as further evidence continues to support this idea.  Our work on EBV and HIV was quite productive and will be the topic of another post.

[ii] We were awarded a prize for this article: The Nellie Westerman  Prize for Research in Ethics awarded by the America Federation For Clinical Research.

When is it best to start antiretroviral treatment: an update

April 13, 2009 2 comments

“Starting HIV Therapy Earlier Saves Lives”

“Study: Treatment for HIV Should Start Earlier”

“Starting Therapy Earlier Found to Improve Survival”

“Earlier HIV Treatment Boosts Survival”

With headlines like these you would think that there is a clear answer to the question of when is it best for HIV infected people  to start antiretroviral treatment.  There can be no doubt at all that starting antiviral therapy early – in this case at a CD4 count above 500 improves survival.  These headlines, addressed to HIV infected individuals their physicians and the public are a unanimous response to a study that just appeared in the New England Journal of medicine (NEJM).  http://content.nejm.org/cgi/content/full/NEJMoa0807252

But is this confidence justified?

Unfortunately, despite these headlines, the study which occasioned them was absolutely unable to justify the conclusion ; we still do not know when it’s best to start treatment.

The study examined data that had been previously collected.  It was a retrospective observational study with all the problems inherent in such studies. These have been outlined in a previous post.

About a week after this study appeared in the NEJM, another large retrospective observational study was published in the Lancet (April 9th 2009

doi:10.1016/S0140-6736(09)60612-7http://www.thelancet.com/images/clear.gif ).

While both studies support the desirability of not delaying a start to antiviral therapy to a CD4 count below 350, they do differ with respect to the reported benefits of starting above that number.  The Lancet study, whose lead author is Jonathan Sterne, finds a decreasing benefit at start times increasing above a CD4 count of 350, with nothing   at starting around 400.

The authors of both reports  agree that prospective randomized studies are the best way to approach a resolution of the “when to start” question – a question that might have already  received a reliable general answer had we begun these studies in 1997, as some of us suggested we do at that time.

Obviously we cannot just wait for the results of randomized prospective studies.  We do need guidelines now, but any recommendation based on available information must be regarded as provisional, until the results of prospective randomized studies are in.  It is important that this be clearly stated. If we are ever going to be able to enrol a prospective randomized study then we cannot afford to delude ourselves that the answer to the when to start question is already known.

While the lead author of the New England Journal of Medicine did pay homage to prospective randomized trials – and a kind of ritualized homage is exactly what it sounded like, this gesture most certainly did not inhibit her from unreservedly recommending an earlier start to treatment, a start even at a CD4 count above 500, without conducting such a prospective study.  Her conclusion:

“The early initiation of antiretroviral therapy before the CD4+ count fell below two

prespecified thresholds significantly improved survival, as compared with deferred

therapy

One of these prespecified thresholds was a count 500 CD4 lymphocytes.

This categorical statement, arrived at by the kind of study that cannot possibly justify such confidence, will have a negative  effect on  enrolment in proposed randomized trials, which are in fact the kind of study that can provide conclusions in which we can have justified confidence.

This study may well be the last coffin nail in any hopes there may have been for the completion of prospective randomized trials designed to address the “when to start” issue.  It may now be impossible to enrol, and will never get off the ground. This difficulty is made so much worse by the kind of uncritical headlines shown above

I wonder how the commentators who rushed so uncritically to announce Dr Kitahata’s conclusion on the benefits of starting treatment at CD4 counts even greater than 500 will respond to the Lancet report, which did not find a benefit with starting at such high CD4 numbers?   I hope I’m wrong in suspecting that this study will be largely ignored; the headlines trumpeting the survival benefit of starting treatment early – even above a CD4 count of 500 will not be marred by any doubt introduced by the study reported in the Lancet.

Among the problems with the New England Journal of Medicine study is that a significant number of people were left out of the analysis, because their HIV disease failed to cooperate with preconceived notions about the course of this disease.

This is a significant criticism and I will try to explain why.  The study examined two groups of people, one with over 500 CD4 lymphocytes, and one with CD4 counts between 351 and 500.

Let’s just take the 351 to 500 group.    Here, deaths in those starting at counts between 351 and 500 were compared with deaths in those starting below 350. Sounds reasonable?   Maybe, until we learn that significant numbers of people with 351 – 500 CD4 cells who did not start treatment  also did not progress to below 350 CD4 cells.   So the authors just left these people out of their calculations. They in effect did not exist for the investigators.

The recommendations the authors make are meant for all people, including those who did not progress and were left out of the analysis.  These people are also going to be treated with drugs they don’t need, as they cannot be identified[i].

I suppose this will do wonders for drug sales, but there will be individuals taking drugs for no reason and some may only suffer their ill effects as well as cost while deriving no benefit.

Here is another serious problem with this study.

Among those people with CD4 counts between 351 and 500, it is important to know just how long treatment was delayed in those who waited until their counts fell below 350.   This information was provided; the median count at the time of starting treatment among all who waited was 286.   But what was the CD4 count at starting treatment among those in this group who died?

This information was not given – at least I was unable to find it.

Could there have been those starting treatment with counts below 100, below 50 – maybe even below 20.   In an extreme example, if a person waited to start treatment to a point close to death, there would not be much surprise that delaying treatment   initiation is associated with a worse outcome.

Many physicians are proud that the field has abandoned uncritical authority as a guide to practice and has now embraced evidence based medicine. David Sackett, one of its originators, has stated that one pillar of evidence based medicine is the use of the best external evidence in making clinical decisions[ii].

All too frequently physicians, while priding themselves on practising evidence based medicine,  somehow are still able to make decisions based solely on their unproven beliefs, as if they have a private source to the truth, some special access to an oracle.  I have  heard one physician state that anyone with a viral load should be treated, another saying essentially the same thing in stating that he would treat every HIV infected patient no matter what the CD4 count. How on earth have they arrived at these conclusions?  Patients might just as well seek advice from a palm reader.

As always you can’t beat the truth. No matter what the private sources of information to which  some physicians and patients apparently have access, the truth remains  that apart from people with under 200 CD4 cells the best time to initiate antiviral therapy is unknown.

I have once before faced this kind of opposition to conducting a randomized prospective study to address the question of when is it best to start treatment.  In the early 1990s I participated in an effort to conduct a trial of early versus deferred treatment with AZT.  A pilot study was initiated, and I participated with some statisticians in describing the study to numbers of physicians in New York City, with the hope of encouraging them to enrol patients.  Despite expressions of enthusiasm, the response was so dismal that the trial could never take place.  However there was one physician – just a single physician in San Jose who was able to recruit many more patients than all the others combined.  He was so successful that we asked him to come to New York City to explain how he was able to enrol so many patients.  His answer was simple.  He told patients the truth. He did not know when it was best to start treatment, so he and his patients let the toss of a coin determine this, as a means of finding out what was best by participating in a study.

This means that the other doctors were unable to say they did not know.  Maybe, as is the case today some actually felt that they did know, as they had complete faith in their intuition, or perhaps had some private access to the truth. For these physicians the practice of medicine is more akin to a faith based activity.  Maybe other physicians  did not know when it was best to start treatment, but might have felt unable to admit this; maybe some patients felt they knew and physicians acceded to their wishes.

The rational response to uncertainty – having first overcome the hurdle of being able to admit that there is uncertainty – is to try to resolve this by the best means available.

I fear we are not even close to recognizing that there is uncertainty about when to start treatment in people with over 200 CD4 cells.  The NEJM article exacerbates the problem with its assumption of certainty, an assumption very sadly shared by some health care providers, some journalists and community commentators to whom HIV infected people turn to for advice.

In conclusion I cannot lose an opportunity to yet again bring attention to the need to individualize therapy.   The rate of HIV disease progression is so widely variable that there are limitations in setting a fixed CD4 count as a guide to start therapy.  A prospective appropriately designed trial can tell us if on average it is better to start above rather than below a certain CD4 count, or on average it is better to start treatment immediately or to defer it.

It is the “on average” limitation that needs fine tuning for each individual patient.

Not only will the rate of disease progression vary widely between patients, but there are other individual considerations that impact the decision to start treatment. For example, adequate housing, mental health issues, co morbidities and many other factors need to be considered.

These two aspects, the general and the particular, fit so very neatly into David Sackett’s description of evidence based medicine that I will quote a passage:

The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research. By individual clinical expertise we mean the proficiency and judgment that individual clinicians acquire through clinical experience and clinical practice“.

BMJ 1996;312:71-72 (13 January) : Evidence based medicine: what it is and what it isn’t.  David L Sackett, William M C Rosenberg, J A Muir Gray, R Brian Haynes, W Scott Richardson

The best available external evidence will be the  results of a prospective randomized trial; these  will provide general guidance.  Individual clinical expertise will apply this to particular patients,  taking into account many factors, not least of which is the patient’s rate of disease progression.

A previous post discusses the  issue of individualization of treatment.


[i] If we took individualization of treatment seriously, we could in fact come some way to identifying rapid and slow/non progressors.  See previous post on individualization of treatment.

[ii] Often forgotten, the second pillar is individual clinical judgement.

HIV TREATMENT AS PREVENTION

March 27, 2009 4 comments

The proposal that testing and treating everyone who is HIV infected would end the epidemic is back in the news.

It is not a new idea. It has been discussed at HIV/AIDS conferences. At the beginning of the year an exercise in mathematical modelling was presented in the Lancet providing some support for this notion of universal testing and treatment. Now some experts in molecular biology and virology have added their personal opinions in favour of this approach; I notice that at least on one web site addressed to HIV and Hepatitis virus infected individuals, the views of these pioneer researchers are reported with, as seems to be usual, no analysis or criticism. http://www.hivandhepatitis.com/recent/2009/032409_a.html

It begins to look almost like an advertising campaign, with the touch of a skilled publicist; an idea is gradually brought to public attention, it is widely endorsed and the hope is that public support will ensure that funders and politicians will move the project forwards.

The merits of the proposal, and the way it is being promoted are two different issues.

Regarding the proposal, in principle it is certainly a worthwhile idea that deserves consideration.
But there are several problems, not mentioned in public reports of this proposal, and barely dealt with in the professional literature, which may constitute insuperable barriers to its implementation.

Leaving aside for the moment the question of whether such a project is even feasible, perhaps the most important problem is that infected people who do not need treatment will be asked to receive it to achieve a social benefit.

This proposal then involves the general concept of a public health intervention on individuals who will not themselves derive any benefit from the intervention, but will only be exposed to its risks.

We have thankfully not yet reached the point where enforced testing and treatment can be seriously proposed. (We may be getting close in the removal of written informed consent for HIV testing).

Certainly the spectre of mandatory testing and treatment is lurking behind this proposal to test and treated everyone infected. This would do wonders for drug and testing equipment sales.

So we would have the situation where some individuals will voluntarily take treatments that despite what we may be told can most certainly not be regarded as absolutely free of possible adverse effects, Many infected people will of course benefit from this. Others however will agree to take risks, with no benefit to themselves but for the benefit of others. Quite apart from many other issues, we can only ask these individuals to participate in the project if there is an overwhelming chance of success. At the moment we do not have this assurance.

It is not a digression to compare this situation with that in which an individual is asked to join a clinical trial and who may be randomly assigned to receive a new treatment of as yet only conjectural benefit. We are absolutely obliged to ensure that the trial design is such that reliable information will be obtained from the study.

Since the testing and treatment of all infected individuals to end the epidemic can in no way be regarded as an undertaking with an assured successful outcome, it really is a trial, based on an hypothesis somewhat supported perhaps by mathematical modelling. As such it will require written informed consent from the participants.

I wonder what such a consent form would look like. It is possible, actually likely, that a consent form outlining possible risks and benefits would dissuade many from participating.
The disincentive would be felt by those infected individuals who do not themselves require antiretroviral treatment.

This inconvenient obstacle can be easily eliminated.

All that is needed is for treatment guidelines to include a recommendation that antiviral treatment should be offered to all infected individuals, even those with greater than 500CD4 lymphocytes. A precedent has now been set where treatment recommendations can be made on the flimsiest of evidence. The inappropriate use of retrospective observations to justify an earlier start to antiretroviral treatment is a good example.

So all one needs to do is to move the goal posts a little further and declare that antiretroviral treatments should be given to all HIV infected individuals, irrespective of CD4 count. There should be no difficulty in selecting retrospective observations that will support this recommendation. In the field of HIV/AIDS you can probably find retrospective data to fit whatever idea you are interested in promoting.

There is another tool available to promote the contention that every HIV infected individual, irrespective of CD4 count will benefit from antiviral therapy. This useful tool is called “expert opinion”. (Actually, people billed as “experts” have already expressed this opinion).

The problem with this is: what does it take to be regarded as an expert?

We may well be in an era where we have “experts” for hire.

Defining what was meant by “expert” was once much easier. Years of experience and significant contributions to the field might have been required attributes. But no longer.

Experts can seemingly be created overnight, at least by commercial entities interested in marketing a product. Their credentials are easily supplied. These instant experts will give talks at conferences, they will appear on educational programs, and even put their names to ghost written articles.

[http://healthcare-economist.com/2008/05/03/ghostwriting-by-pharmaceutical-companies/

Revealed: how drug firms ‘hoodwink’ medical journals Pharmaceutical giants hire ghostwriters to produce articles – then put doctors’ names on them.
http://www.guardian.co.uk/society/2003/dec/07/health.businessofresearch
]

As for the practice of ghost writing , there is a great deal of evidence for this, a little shown above. I’m ashamed to admit that I once (only once many years ago) allowed an employee of a drug company to write an article which carried my name. But I had done the work without their support, and in my defense, I checked every word, changing some, – an experience the writer was evidently not used to. This was my first (and only) personal encounter with this practice

I will hazard a prediction; before the year is out we will have arrived at the point that experts will state that every HIV infected person benefits from treatment, irrespective of CD4 count. If required we will see retrospective observational studies which show that in people who started treatment above a CD4 count of 500, mortality from all causes was reduced as compared to those starting below 500 CD4 cells. It should be just as easy to find retrospective data that shows that starting treatment immediately on diagnosis confers a benefit not seen when treatment is delayed to CD4 count of 350.

Of course these expert views will be very widely disseminated in press reports and on numerous web sites – some will even provide the opportunity for doctors to earn CME credit. In this way conjectures are transformed into established facts.

I don’t know how we might obtain real evidence that testing and treating all infected people is not only feasible, but would achieve its goals. The two are related.

For example, how does one ensure that all people are tested? Or that they will agree to be treated? Or that they will adhere to their treatments?
As imperfect as this is maybe one approach is to test these issues in a limited setting where mobility in and out of the selected areas can be controlled for.

This could more usefully be a trial where two different strategies were compared – the present practice of starting treatment at 350 CD4 cells, and treating everyone infected, while promoting HIV tests in both groups. Despite complications introduced by the movement of people, we might get an idea if this is a feasible and effective approach.

Sadly those bodies that instruct physicians on how to treat HIV infected people, and who tell HIV infected people what is best for them, seem to be averse to calling for prospective studies, designed to shed some light on what may in fact be best for infected people. Those who manufacture the treatments appear to prefer trials that are designed to provide them with the answer most congenial to them. Here is an account of the practice of designing trials to provide the answer most desired.
[http://www.washingtonpost.com/wp-dyn/content/article/2008/07/14/AR2008071402145.html]

They can also rummage in retrospective data collections selecting observations best suited to the outcome they have already decided on. Of course there is always an expert to be created to promote this outcome.

When the mathematical modeling referred to above supporting the idea of a “test and treat everyone infected” approach appeared, I wrote a reply to the Lancet which published the article. Not my letter, which was politely rejected.
I am adding a slightly edited copy of that letter here.

A recent Lancet article suggests that we could end the HIV epidemic by testing and treating all who are infected, irrespective of whether or not the individual would benefit from such treatment (R. Granich et al. 2009 Lancet 373:48).

This represents an intervention on individuals, primarily for a public health benefit. At the present time, ethical considerations make this proposal a completely indefensible approach.
The available drugs are far from benign; for a particular individual, their use is desirable and justified when their benefits clearly outweigh their risks. Treating individuals to achieve a population benefit requires a similar risk benefit assessment. F M Hodges and colleagues have addressed this issue. (EM Hodges, JS Svoboda, RS van Howe
Prophylactic interventions in children: balancing human rights with public health. J Med Ethics 2002; 28: 10-26)

To protect individual liberties they propose six conditions that should be met before for such interventions are taken. All of these are reasonable. I quote a passage from their article that outlines them.

“PROPHYLACTIC INTERVENTIONS FOR PUBLIC HEALTH BENEFIT”
Prophylactic medical interventions are frequently performed on healthy individuals who have given informed consent. …..
The most common example arises when the patient is at significant risk of contracting a life- and public health-threatening illness for which the proposed prophylaxis is a proven preventive. In order to safeguard individual liberties, the situations in which such procedures may be undertaken for public health benefit must meet the following requirements:
1. The danger to public health must be substantial.
2. The condition must have serious consequences if transmitted.
3. The effectiveness of the intervention in safeguarding the majority of the public against the particular malady must be well established.
4. The intervention must be the most appropriate, least invasive, and most conservative means of achieving the desired public health objective.
5. The individual must be provided with appreciable benefit not dependent on speculation about hypothetical future behaviours of the patient.
6. The burden to the individual’s human rights and health must be balanced against and found to be substantially outweighed by the benefit to society in helping prevent a highly contagious disease or other potentially calamitous condition from affecting the public health”.
Clearly the proposal to treat all infected people will include some in whom the fifth consideration will not be met, but the concerns are covered in the sixth one. But here the benefit to society must be assured, or more practically, be considered to be highly probable, with credible evidence produced to support the contention (as stated in the third consideration).

While the first two criteria are very clearly met, the present proposal to treat all who test positive fails utterly on the third point. It is far from well established that antiviral treatment of all who are infected will protect the “majority of individuals” in diverse settings. Among problems acknowledged by the authors are those related to toxicity, adherence and the development of resistance to the antiviral drugs. To this must be added the possible negative effects on behaviour deriving from a perception of being non infectious. The fourth condition is also not met. We cannot state that we have exhausted the utility of prevention education and promotion of condom use.

Let alone the questionable wisdom of mounting an extensive and expensive public health intervention that is based only on mathematical modeling, we are very far from possessing information that would supply the slightest confidence that such a measure would effectively meet its objective.
Regarding adherence, the optimism presented by the authors based on studies in Malawi is hardly justified. Adherence by individuals who may be ill, and certainly know they are receiving medications for their own benefit tells us nothing about adherence by people who feel healthy and know they are not taking the medications to benefit themselves.

The general relationship between viral load and infectivity is well established. The success of the proposed strategy according to the model presented depends on achieving a significant reduction in viral load from the pre-treatment value. The solid evidence of the potent ability of antiviral drugs to very substantially reduce viral loads in a sustained fashion derives predominantly from observations in settings where untreated endemic or concurrent infections are uncommon. The ability to achieve a sustained significant drop in viral load may be more difficult where there is a high prevalence of untreated endemic or associated infections. This is the case in parts of Sub Saharan Africa. Many of these infections are able to activate and enhance HIV replication, through the action of pro inflammatory cytokines. Should these infections be associated with genital ulceration there are additional uncertainties.
HIV disease is characterized by an enormous variability in the rates of disease progression. There is no such thing as a standard course of disease progression that is one of the assumptions used in the modeling. We know very little about the distribution of different rates of disease progression among infected individuals, or about the influence on this of associated untreated infections.
Risking individual harm for a public benefit is a slippery slope. Will we see a proposal to administer (with consent, of course) antiretroviral medication to the whole sexually active population, HIV infected or not?

AIDS is a preventable disease. We have far from exhausted less conjectural, as well as less speculative approaches to its prevention.

Addendum
Apart from this proposed strategy to treat all infected people, there definitely are situations where treatment as prevention is absolutely appropriate and desirable. One is post exposure prophylaxis (PEP), where individuals who have been exposed to HIV attempt to prevent infection by rapidly taking antiretroviral drugs – that is within 72 hours of exposure. This applies to both occupational and sexual exposure. Regarding sexual exposure – where feasible, which is certainly the case in N America Europe and in many other regions, a 3 day supply of drugs should be available 24 hours of the day, given the limited time frame for action. Measures to immediately start PEP immediately should of course be available where occupational exposure is a risk. Emergency departments should be equipped and ready to start the protocols for PEP. People at risk should even be encouraged to keep a 3 day supply of drugs at home to cover times when medical care is not available – at night or weekends. .Very importantly people at risk must be informed of the availability of PEP.

The second is pre exposure prophylaxis. This is taking antiretroviral drugs on specific occasions when there might be a risk of exposure. This absolutely cannot replace the use of condoms, but some individuals may wish to take an additional even if unproven preventative measure. This really is a matter for individual choice. Our obligation is to make it very clear that this is not a substitute for condoms.

Individualization of HIV therapy

March 8, 2009 1 comment

Why treatment of HIV infection must be individualized.

HIV disease is usually a progressive disease. That is, it has a starting point; the time of infection. The disease then progresses, and without treatment will generally end fatally. There are some very fortunate HIV infected individuals who are able to control viral replication and remain disease free. But for most, HIV disease does progress. But, for each individual, the rate at which it progresses varies widely. Disease progression is reflected in the fall in the numbers of CD4 lymphocytes.

So any single CD4 count measurement is really a point on a descending curve, one that does not necessarily proceed in a straight line, and falls at widely differing rates in different individuals.

Recommendations for the treatment of HIV infected individuals are issued periodically by DHHS and bodies such as the International AIDS Society. These recommendations, particularly those concerning when to start antiviral treatment, have always included a particular CD4 count as a signal to start or to consider starting antiviral treatment.

All individuals with a CD4 count of less than 200 should be on therapy. They are in great danger of acquiring a possibly fatal opportunistic infection and evidence derived from clinical studies makes it absolutely clear that antiretroviral treatment is life saving.

But what about people with higher CD4 counts? Here there is uncertainty about when in the course of HIV infection it is best to start treatment. Of course, if the drugs were completely harmless (including cost) it might be less important to have an answer to this question. However the drugs can have significant adverse effects, some of which only become evident after years of use. For people with fewer than 200 CD4 lymphocytes, the benefit of antiviral treatment overwhelmingly outweighs the risks.

For others, a very mixed group, with CD4 cells anywhere from 200 to over 1000, and each with a different rate of disease progression, we cannot, with any security, make a “one size fits all” recommendation as to when it is best to start treatment.

The best way to resolve clinical uncertainty remains randomized prospective clinical trials. By now we might already have obtained reliable evidence as to whether, on average, it is best for infected individuals with more than 200 CD4 lymphocytes, and who have no symptoms, to start antiviral treatment immediately, or to defer it. (A suggestion made in 1997 when the first guidelines were issued: http://aidsperspective.net/articles/guidelines1.pdf )

The current recommendations, regarding people with greater than 200 CD4 lymphocytes, and who are without symptoms, propose a CD4 count of 350 as a point to start treatment ( many believe this number should be 500). This recommendation is made for all individuals – it is a one size fits all approach[1]. This kind of approach is appropriate for some aspects of treatment; for others it is very wrong[2].

Perhaps the most important  example of a  recommendation, where its application across the board  is problematic,  is that which deals  with the time when antiretroviral treatment should be started in individuals with greater than 200 CD4 lymphocytes.  This recommendation specifies a specific CD4 count at which to start. As noted, for individuals with a CD4 count below 200, there is no doubt that they will benefit from therapy. For others who have no symptoms, specifying a CD4 count for all is mistaken. It is here that individualization is necessary.

The reason is that no two HIV infected people are the same with respect to the rate of disease progression. During the early years of the epidemic, before antiretroviral treatment was introduced, we soon noted that the CD4 count declined at different rates in different people, and not necessarily in a straight line. As noted, at one extreme, there were the few fortunate individuals in whom there seemed to be no disease progression, at the other there were the few people whose CD4 cells fell very rapidly after infection, and who did not survive for more than 2-3 years, but most fitted somewhere between these extremes .

To illustrate this I have considered four possible situations. This is a picture of the possible rates of CD4 decline in four different individuals. . It is true that these pictures are constructs, but they do accurately reflect the observed variability in disease progression; real examples showing this variability would be easily found in my medical records, and of course in those of other physicians during the period between 1981 and about 1993.

The dip in CD4 cells following infection is usually seen when there is an opportunity to observe this. CD4 cells then rebound to a level called the set point, which will be different in relation to the pre infection level in different people. From then on it declines, but at a very variable rate, and can remain steady for varying periods before declining, again at varying rates.

img049

Look at where three of them (A ,B and C) reach a count of 450 CD4 lymphocytes; A (an unusual rapid progressor) gets there in about one year, B in about 3 years, C in 7 years, and D, who is a fortunate non progressor is nowhere close after 18 years.

The arguments for starting early are not only to forestall reaching the dangerous level of 200 CD4 lymphocytes. The continuous deterioration of the immune system and diminished chances of recovery at lower counts are also arguments for an earlier start. There is also the possibility that there is a greater incidence of cancer, – other than lymphoma and Kaposi’s sarcoma, at higher CD4 counts in HIV infected people. If this is so then it remains to be shown how frequently these events occur and whether antiviral therapy can avert them.

Treatment itself, particularly if extended over many years, is not without risks, some of which cannot even be completely known yet, particularly with the newer antiviral agents. We have to do the best we can in making a risk benefit assessment. In order to do this we should attempt to obtain information on the rate of disease progress in any one individual. This may not be entirely possible, as the rate of disease progression in any one individual may not be steady; it may accelerate or slow down. But it is possible to obtain a good, if not perfect, picture of the course of HIV disease in any one person.

How might we obtain some information about a given individual’s rate of disease progression? Apart from obvious exceptions, and in people below 200 CD4 cells, there are no emergencies in HIV medicine. For each person we generally will have time to observe the CD4 count and viral load over a period of 6 to 12 months and obtain some idea of the rate of progress. A rapid fall in CD4 count might result in a decision to start in less than six months of observation. Or a consistent fall in CD4 count might lead to a decision to start treatment at CD4 numbers higher than even 500. This is far from perfect, as changes in CD4 cell numbers do not necessarily follow a straight line. But it is far better than basing a decision on a snapshot – which is what the experts are telling us to do.

Individualization involves more than considering the rate of disease progression. There are other factors, such as associated diseases, domestic and social circumstances such as a lack of housing, as well as mental health issues, and many other considerations that are involved in individualization. Observing people also provides the time to establish a doctor patient relationship and for the physician to become familiar with the patients particular circumstances.

The natural history of untreated HIV disease is relevant to the “when to start treatment” issue and will be the topic of the next post.


[1] Evidence supporting the recommendation is derived in part from retrospective observations. The reasons why these are unreliable guides are outlined in the previous post. It is critical to as far as possible, eliminate bias in study designs because this increases the probability that a particular outcome can be interpreted as indeed resulting from a particular intervention. In this case it would be that improved survival is due to an earlier start of antiviral therapy and that the medications mediate the effect – and not for example, from simply being under the supervision of a physician. Retrospective observations, that is, looking back at information already gathered cannot be free of confounding factors as described in the previous post. In a prospective study people would be randomly assigned to receive immediate treatment or to defer it. This will give us the most reliable answer to the question of which approach is better on average.

[2]Examples of measures that should be taken in the treatment of every HIV infected person, irrespective of the rate of disease progression are the types of tests that are performed on the initial assessment of an infected person. For example, the initial assessment of an HIV infected person should always include not only CD4 counts and HIV viral load measurements, but also tests for hepatitis, toxoplasmosis, and many other investigations. Another example of an intervention that is appropriate for categories of infected people is treatment to prevent Pneumocystis pneumonia in people with less than 200 CD4 cells. And of course, people in this category must always be offered antiretroviral therapy.

aidsperspective.net

March 6, 2009 1 comment

Today, March 6th 2009, I have moved this blog to aidsperspective.net/blog.  All new posts will be to that site.

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When is it best to start antiretroviral treatment

February 26, 2009 Leave a comment

When is it best to start antiretroviral treatment?

The issue of when it is best for asymptomatic HIV infected people with more than 350 CD4 cells to start treatment with antiretroviral drugs has received renewed attention lately. Reports at recent conferences and discussions of these reports on several websites all seem to favour an earlier start than at a CD4 count of 350. There is absolutely no reliable evidence to support this recommendation. The evidence that is presented derives mostly from retrospective observations. Such retrospective studies cannot provide reliable evidence that improved clinical outcomes in those starting treatment earlier are actually caused by the antiretroviral drugs. That this is so can only be an hypothesis, a theory to be tested by prospective studies. Such a prospective study would essentially follow people who are randomly assigned to start treatment immediately or to defer it.

Some of the problems associated with interpreting retrospective observations are outlined at the end of this post1.

The “when to start” issue of course only applies to infected persons who are symptomatic and have a CD4 count above 350. For those with fewer CD4 cells there is no doubt at all that such individuals should be on therapy.

If the antiviral drugs were completely harmless, with no toxicity, we would have no problem at all, apart, of course from the financial toxicity. However the drugs are not without problems, particularly if we are dealing with taking the medicines for a life time. The newer drugs are touted as being less toxic. However it takes years for some toxicities to become manifest. How many years were people taking Zerit, (D4T,stavudine) before we knew about its effects on fat distribution? Another example of toxic effects only becoming apparent after years of use is thinning of bones caused by some antiviral drugs.

When potent antiretroviral agents were introduced in the 1990s their impact on reducing mortality was unequivocally demonstrated in persons with more advanced disease. This immediately left us with a question regarding the effect of starting these drugs in individuals with less advanced disease.

Rather than admitting that the answer to this question was unknown, and required to be studied in a prospective fashion, the Department of Health and Human Services issued a set of guidelines. It is understandable that issuing guidelines, in the face of uncertainty is reasonable, but they must be regarded as interim, pending the outcome of studies.

In 1977 I wrote a letter in response to the publication of these guidelines; it was received by the Guidelines Committee, but I was sent absolutely no response. The letter can be seen here: http://aidsperspective.net/articles/guidelines1.pdf

Despite attempts to rely on retrospective observations to resolve clinical uncertainty, – such as uncertainty about when to start antiviral treatment, prospective randomized trials remain the best way to achieve this. They minimize bias, and thus misinterpretation, and are therefore the most reliable way to resolve uncertainty. There is no getting over this. Such trials may be expensive, and last a long time, but in the end, probably more time and money is lost by repeating inconclusive and conflicting retrospective studies.

As always, you can’t beat the truth. Regarding the “when to start” question, the truth was and still is that the answer to the question is unknown. Again, if the drugs were harmless there would be no problem. But it is quite possible that a person starting treatment at say 700 CD4 cells, even 500 CD4 cells, who may be a slow progressor may well have his or her life shortened by long exposure to the medications.

If, for whatever reason one presumes to favour a particular answer one can always select snippets of data to support one’s bias. Many would like to believe that it is better to start early. I have even read on one web site, that a New York physician stated that he would start any infected person on treatment no matter what the CD4 count was. I suppose this physician, and those who share this view are happy to practice with only their unsupported beliefs as a guide. This is as reliable as using a crystal ball and sick people deserve more from their health care advisers. In this respect the writers reporting such nonsense generally make no comment on the danger of views based only on belief, thereby adding credibility to these statements of faith. The practice of medicine is not a faith based activity.

The scientists who attach unwarranted importance to retrospective studies are also doing a disservice to clinical research. Some at the recent CROI meeting did admit that a prospective randomized trial was the best way to obtain reliable evidence on the issue of when to start. But as reported on one web site:

“Professor Doug Richman of the University of California San Diego questioned whether a ‘when to start’ trial was worth the expense. “Rather than spend millions on a trial, given that most people aren’t diagnosed until much later, why not use all that money to identify people who have the higher risk?” he asked”.

Similarly:

“He [Bartlett] also believes that the field is not willing to wait the 5 to 10 years necessary to generate an answer on when to start therapy.”

Discovering what is in the best interests of the infected person is not worth the expense? Waiting 5 to 10 years to find out is unacceptable?

So if we dispense with the truth to inform our actions, what could it be that guides us? Whatever it is, it is certainly no more reliable than consulting a palm reader.

Interpretations of associations found in retrospective studies presented as reliable indicators of a cause and effect relationship, rather than possibly suggestive of such a relationship, have as much meaning as the interpretations of an astrologer. Of course such data may be useful in suggesting hypotheses.

At a recent ICAAC meeting Dr Kitahata presented an analysis of a large retrospective study comparing outcomes among people starting at a higher as compared to a lower CD4 count. There was little meaningful criticism of the interpretation that the improved outcome in those starting treatment earlier was actually due to medications taken. Dr Kitahata felt that it was possible by some statistical magic for retrospective observations to mimic a randomized prospective study.

Here is an illustration of the interpretive pitfalls in such studies; it is a comment I sent to the web site reporting the results and conclusions of retrospective studies. I used the name James Mello, and pointed out that, as an example people who started treatment earlier were more likely to be under medical care than those who started later, and this might have contributed to their better survival. Another possibility is that most of the mortality might have occurred in those with the lowest CD4 counts; the examples I gave in my comment were a CD4 count of 1 compared to 349, when in fact the study concentrated on individuals with counts above 350. There are other possible explanations. There was one comment that suggested the possibility that people who choose to start treatment early are more likely to be concerned with their health in general and thus more prudent, and presumably more cautious in risk taking.

This is the comment of James Mello:

http://aidsperspective.net/articles/mello.pdf

Another retrospective study actually showed no survival benefit in people with CD4 counts above 450. Here is a report of this study and that of Dr Kitahata:

http://www.medpagetoday.com/MeetingCoverage/CROI/12819

Surely we need to know, and not guess when it is best to start treatment.

There are those who favour an earlier start and may have reasonable ideas to support these views. But they remain views – not proven ways to proceed that are in the patient’s best interests.

Let us find out if it is a fact that there is a benefit to starting earlier. All of us – HIV infected people and their advocates should be calling for appropriate prospective studies to guide us. We need to know the truth about when it is best to start.

Even if we were to conduct an appropriate large randomized prospective study we would only know if in asymptomatic HIV infected people with greater than 350 CD4 cells, it is on average better or worse to start treatment early or to defer it or if it makes no difference, of course apart from the expense.

This brings up an associated extremely important but neglected issue. This is the need to individualize therapy, which will be the subject of the next post.

1.

The causative interpretations of retrospective observations are made difficult by what are called confounding factors and some are impossible to overcome. For example we don’t know why people choose or agree to start treatment early or defer it. The different decisions may reflect the possibilities that those choosing an earlier start may have better access to medical care, and receive better care in general, or may be more likely to be people concerned with their overall health.

Here is another example of something that might make interpretation of retrospective observations difficult. The largest study compared the outcomes in people starting treatment with over 500 CD4 cells with those starting between 350 and 500 CD4 cells. The rate of progression of HIV disease varies enormously. So, one individual with a CD4 count of 400, may progress very slowly, whereas another person with 400 CD4 cells may be on a rapid decline, and already starting to feel unwell. We don’t know if people who are progressing rapidly and maybe beginning to feel unwell at even 400 CD4 cells are overrepresented in the group that started treatment late. If this were so it would certainly influence the outcome; had the person with 400 CD4 cells starting antiviral therapy at that count, been a person with very slow disease progression we might have seen a different result. It may be possible to control for some of these factors but not for all the possible factors that interfere with a clear interpretation that it is the antiviral drugs that cause the improved survival of people starting treatment early.

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The importance of individualized treatment.

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