Posted on May 19th, 2010 No comments
The most recent revision of the US Department of Health and Human Services (DHHS) guidelines for the treatment of HIV/AIDS recommended initiation of anti-retroviral treatment at a CD4 count of 500.
This recommendation was made in the absence of evidence from a prospective randomized clinical trial. Instead, evidence of inferior quality was relied on.
Much is at stake for HIV infected individuals. The point in the course of HIV infection when treatment is initiated can affect the duration and quality of life.
Rather than issuing interim guidelines pending the completion of a prospective randomized trial the guidelines committee has jumped the gun, relying on evidence of inferior quality.
In the following article, John Falkenberg reminds us of the harm that has resulted from basing recommendations on observational cohort studies.
John Falkenberg New York, NY
Doctors and patients always have the right to choose treatment that is not based on data generated from well-designed clinical trials. However, I worry when treatment guidelines are based on cohort studies or anecdote, and it’s alarming when the city of San Francisco and Project Inform endorse that practice.
No study is cited more often than NA-ACCORD, an observational cohort study, to support early antiretroviral therapy. Besides the many historical examples of harm caused by treatment guidelines based on observational studies (see the Nurses’ Health Study, below), NA-ACCORD suffers from more than the self selection bias of observational studies: a large percentage of the deferred treatment group, approximately 45%, did not initiate therapy and/or did not have a decline in CD4 counts. How can those findings be extrapolated to clinical practice? In addition, the early treatment group may have had incomparable medical care. For example, were lipids more carefully monitored in that group resulting in more aggressive use of statins, a class of drug with pleiotropic effects that include improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. These drugs have demonstrated morbidity and mortality benefits in clinical settings where lipid levels are normal.
The history of HIV treatment guidelines is an excellent reminder of the risk of formulating guidelines based on observational studies and anecdotal evidence. However, HIV is not the best example. There are clinical settings where “more compelling” cohort data using medications considered relatively safe served as the basis for treatment guidelines that ultimately were proven wrong at a significant cost.
I think the best example pertains to the use of hormone replacement therapy (HRT) in postmenopausal women. There were many anecdotal, observational and retrospective reports of the many benefits of HRT, but the Nurses’ Health Study was the flagship. The Nurses Heath Study was a case control, observational study of over 120,000 nurses, including over 20,000 who were post menopausal. As the follow up continued for years, an increasing number of women reached menopause, and various health variables were monitored and reported. The most striking “conclusion” of this study was that the relative risk of death was 0.63 in HRT users vs. non users. The risk of major coronary artery disease among HRT users was 0.60 when compared to those who never used HRT. Both of these findings were statistically significant. These data were broadly reported in medical journals, and professional meetings. The data were added to the HRT prescribing information and aggressively promoted by the pharmaceutical industry, particularly the manufacturer of Premarin (American Home Products, renamed Wyeth, recently acquired by Pfizer), the most widely prescribed HRT.
There was huge resistance to conducting a prospective randomized controlled trial in this population. “It denies the placebo-controlled group the protective heart benefits of HRT.” “It is unethical to randomize people who would clearly benefit from HRT to placebo.” “No one would enroll in this trial considering what we already know about the benefits of HRT in this population.” Despite the criticism, the Women’s Health Initiative, a prospective randomized controlled study of HRT in postmenopausal women was conducted. In July 2002 the study was halted early due to a statistically significant excess risk of heart attack, stroke and breast cancer in those receiving HRT versus those on placebo; a finding that literally rocked the world of HRT.
More recently, long-term treatment recommendations in diabetes were debunked by results from the first well designed, randomized controlled study (coincidently named ACCORD), with cardiovascular clinical endpoints. Using multiple medications for intensive glucose lowering and intensive blood pressure reduction did not reduce cardiovascular events but only increased adverse events. Once again, guidelines formulated without data derived from controlled clinical trials did more harm than good.
There is a lot at stake here and I fear that this is déjà vu all over again. The NA-ACCORD results are compelling and generate a hypothesis that needs to be tested, but the clinical trial has yet to be performed and the evidence is absent. I find it difficult to understand why those of us who have lived during decades of this epidemic, who have seen those living with HIV experience a wide range in the rate of disease progression, and who have seen the rise and fall of early antiretroviral therapy, do not demand more. I’m shocked by both the city of San Francisco and Project Inform.
I cannot claim to know the motivation behind the current push for early treatment without evidence. However, I do know the pressure felt by the pharmaceutical industry as they approach a patent cliff with little in the advanced research pipeline and significant overcapacity. It is not coincidental that lobbying efforts have been stepped up in an economic climate where value driven medicine is a new priority. That lobbying includes an aggressive push to eliminate informed consent for HIV testing and a push for early treatment. And, here we are with major public health agencies and CBO’s jumping on the bandwagon without the evidence
Posted on May 19th, 2010 No comments
The revised USPHS guidelines for the treatment of HIV/AIDS
Guidelines for the treatment of HIV/AIDS were first issued by the US Department of Health and Human Services (DHHS) in 1998. They have undergone numerous revisions since then; the most recent was in December 2009.
The first guidelines were issued shortly after potent antiviral medications became available. We knew very little about how best to use these drugs at that time, and with only a few years experience our knowledge of their adverse effects was understandably limited.
Perhaps the only reliable information we then had was that individuals with fewer than 200 CD4 lymphocytes received a life saving benefit from their use.
Despite such limited information the panel that had been convened to write the guidelines made firm recommendations for the use of antiviral drugs in groups of patients for whom evidence of a net benefit was lacking.
Even in the absence of experience with the newer antiviral agents, at least two probable problems associated with their use could have been anticipated in 1997. The propensity of just about any microorganism to develop resistance to antimicrobial agents was no mystery. Nor was it a surprise that adverse reactions to new drugs appeared as they were used for longer periods.
As might have been anticipated healthier HIV infected individuals have not infrequently had to deal with both of these problems.
Why then did the first HIV/AIDS treatment guidelines panel not propose and encourage the conduct of a randomized prospective clinical trial to answer the question of whether immediate or deferred treatment with antiviral drugs could or could not prolong life and improve its quality or made no difference apart from cost?
Since the problems that were to arise could have been anticipated, if not their extent, the guidelines committee must have accepted that whatever evidence existed was sufficient to reassure them that there would be a net benefit to starting treatment at 500 CD4 lymphocytes.
The most recent revision of the DHHS guidelines now propose, as the first guidelines did, that treatment be initiated at a CD4 count of 500. A prospective randomized trial that directly addresses the question of when treatment is best initiated has yet to be completed. In the absence of information from such a trial the committee has relied on evidence from some large retrospective observational studies.
In the next post John Falkenberg writes about some previous experiences where advice based on results of retrospective analyses of observational data had to be reversed when the results of randomized controlled studies became available.
I believe the biggest mistake made in 1997 by the guidelines committee was in not responding to the very real possibilities of dangers associated with early treatment initiation by encouraging the completion of a prospective randomized trial, such as START, that could by now have reliably provided an answer to the question of whether immediate or deferred treatment is better or worse or makes no difference that is, apart from cost.
It’s not the benefits of early treatment that are in question. Of course there are benefits, but the question we need an answer to is when in the course of HIV disease the benefits of treatment outweigh the risks.
Long term exposure to antiretroviral drugs can have harmful effects. It can take many years to recognize some of these adverse effects. For example we learned only in the last few months that under certain circumstances neurocognitive function improved in some people who stopped antiviral drugs (ACTG 5170).
So the challenge is to find out how best to use the drugs. Put another way, we must find ways to safely minimize exposure to the drugs, which until we have drugs without significant adverse effects, is what determining the optimal time to start treatment is all about. We don’t know if a person deferring treatment until a CD4 count of 350 will or will not live longer with an overall better or worse quality of life than someone starting at 800 or even 500 CD4s.
We do know that at 350 CD4s, benefits of treatment far outweigh risks. But no matter what NIH guidelines committee members may feel, we do not yet have the most reliable evidence that benefits of treatment will outweigh risks when starting at higher numbers.
The wording of the USPHS guidelines is such that depending on whose vote one goes with, I suppose might even be interpreted to mean a recommendation for every HIV positive individual to receive treatment irrespective of CD4 count.
A letter written to the DHHS panel in 1997 suggesting that a randomized prospective trial be encouraged to provide guidance for individuals with greater than 200 CD4 lymphocytes remained unanswered although received.
Sadly the repeated changes to the guidelines since their first appearance in 1998 appear to indicate a retreat from evidence-based recommendations. Maybe this should be stated as a retreat from attempting to find the most reliable evidence on which to base recommendations. The guidelines panel go to great lengths to reassure us that their recommendations are indeed evidence based.
But as they recognize, the quality of evidence can vary. They also recognize that evidence of the highest quality is derived from the results of prospective randomized trials. Yet not only do they not vigorously encourage the completion of such trials, their recommendations actually inhibit enrolment into START which is such a trial.
Unfortunately the DHHS recommendations while not binding have a huge influence. Remarkably they are even regarded by some as setting an ethical standard, so that fears have been expressed that enrolment into START might be considered unethical as the current guidelines revision recommend starting treatment at 500 CD 4 lymphocytes.
Thirteen years after the first guidelines were issued, the DHHS panel has now made revisions that continues to threaten enrolment into a randomized controlled trial that will provide clear guidance to HIV positive individuals and their doctors about when to initiate antiviral therapy.
Surely, when we recognize that reliable evidence is lacking to inform a very important clinical decision, is it not our obligation to seek the evidence, rather than settle for the uncertainties associated with evidence of inferior quality? This is not only for the benefit of our patients but also to affirm that our stated respect for evidence-based recommendations is more than lip service.
At this time the DHHS guidelines are the only ones that recommend a start to treatment at 500 CD4 lymphocytes.
The DHHS guidelines have been of benefit to people with HIV/AIDS. But on the issue of when to start antiviral therapy they have not best served the interests of HIV positive individuals.
We need a randomized controlled trial to answer this question, not the votes of a committee.
I believe that many health care providers would welcome the opportunity to be able to present an option to their patients with greater than 350 CD4s, to enrol in a study such as START.
At the end of the day, determining when it’s best to start is not something you vote on. It’s something so important that you nail it down with a trial such as START.