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Published byRalf Morris Modified over 9 years ago
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Background Appropriate time to start HAART is still debatable 1995: “Time to hit HIV, early and hard” Eradication thought to be possible Early regimens had a lot of toxicity: CD4 200 Not 500, not 200, 350 than.
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Study outline Study Design: cohort/observational Patients stratified according to CD4 count at baseline. Two groups of interest CD4 350-500 and CD4 > 500. Early –therapy: HAART started within 6 months of CD4 count within prespecified range Deferred-therapy: HAART started after transition into lower CD4 count range
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Study outline Setting: Patients from 60 sites managed by 22 research groups based in Canada and US Participants: 17,517 asymptomatic patients with HIV infection who received care during the period of 1996-2005 and were therapy naïve. Data Collection: methods are not uniform. Some site collect prospectively, others retrospectively. Main Outcome: death from any cause
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Results
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Patients in deferred groups more likely to have HCV and hx of IVDU. Patients with CD4 > 500 that deferred Rx were less likely to have HIV RNA < 500 copies/ml 12 after initiation of Rx.
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Results Adjustments also made for HCV status and Hx of IVDU Analysis done with exclusion of data from each cohort
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Results
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Strengths Feasible study design/External validity Death from all causes as end point Sample size Good vital systems: decrease in ascertainment bias Data available before intervention: decrease in lead time bias All strategies possible tested: interruption is bad Sophisticated analytical methods
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Weaknesses Is intervention a marker for good outcome? Differences in exposure to health care and follow-up not addressed Health-seeking behavior (e.g., dif in viral suppresion) “Good Dr.” effect ~45% did not change CD4 stratum and not analyzed= slow progressors? Cause of death known in only 16% No KM curve. Lack of central lab Effects of resistance and long term toxicity not addressed (and maybe not possible addressed)
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Preliminary discussion points: Making decision on treatment based on observational data: The HRT example When decision to treat is marker for good outcomes or a marker for bad outcomes Can we or should we have a RCT for each and every intervention?
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