Is there a trial effect in HIV clinical trials?: identifying who participates in clinical trials and assessing the effect of trial participation on the response to highly active antiretroviral therapy Public Deposited

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  • March 20, 2019
  • Menezes, Prema
    • Affiliation: Gillings School of Global Public Health, Department of Epidemiology
  • There is a widespread belief, that participation in a clinical trial provides an additional benefit called a trial effect. In HIV infection this claim appears to have been unexamined and therefore is unsubstantiated. Evidence of a trial effect may be confounded by systematic differences between trial and non trial participants. Women, minorities and heterosexuals represent an increasing proportion of HIV infected persons but are reportedly underrepresented in clinical trials. We examined if gender/sexual orientation or race/ethnicity differed by trial participation and if there was a trial effect in HIV clinical trials. Using the UNC CFAR HIV/AIDS Clinical Cohort we conducted a cross sectional study of 738 antiretroviral treatment naïve HIV positive adults. Of these, 30% initiated highly active antiretroviral therapy (HAART) in 13 different clinical trials. Subjects were characterized as trial participants if HAART was initiated in a clinical trial. Heterosexual men and women participated in trials at the same rate as men who have sex with men (PR 0.79, 95% CI 0.57, 1.11 and PR 0.97, 95% CI 0.94, 1.66 respectively). Blacks were slightly less likely than non blacks to participate in clinical trials (PR 0.80, 95% CI 0.60, 1.06). This lack of substantial race/ethnicity and gender differences between groups supported our further investigation of a trial effect. For this analysis virologic success was assessed within strata of early (1996-1999) and current (2000-06) HAART periods and was defined as a plasma HIV RNA [less than or equal to]400 copies/ml at six months post HAART initiation. Trial participants initiating HAART in the early period were more likely to achieve virologic success than non trial participants (RR 1.33; 95% CI 1.15, 1.54), but this difference was not observed in the current period (RR 0.98; 95% CI 0.87, 1.11). We found no difference in participation rates between women contrasted with men and a small insignificant difference for blacks contrasted with non blacks. In the current HAART period, both trial and non trial participants were equally likely to achieve virologic success suggesting that there is no evidence for a trial effect. These results suggest that data from HIV clinical trials can be generalized to clinical practice.
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  • Miller, William
  • Open access