• Article

The utility of a composite biological endpoint in HIV/STI prevention trials

A human immunodeficiency virus (HIV) as a biological endpoint in HIV prevention trials may not be feasible, so investigators have used surrogate biological outcomes. In a multisite trial, the epidemiology of STIs may be different across sites and preclude using one STI as the outcome. This study explored using a composite STI outcome to address that problem. The combined biological endpoint was the incidence of any of six new STIs (chlamydia, gonorrhea, trichomonas (women only), syphilis, herpes simplex virus type 2 infection and HIV) during a 24-month follow up period. We investigated how a composite STI outcome would perform compared to single and dual STI outcomes under various conditions. We simulated outcomes for four populations that represented a wide range of sex and age distributions, and STI prevalences. The simulations demonstrated that a combined biologic outcome was superior to single and dual STI outcomes in assessing intervention effects in 82 % of the cases. A composite biological outcome was effective in detecting intervention effects and might allow more investigations to incorporate multiple biological outcomes in the assessment of behavioral intervention trials for HIV prevention


Hartwell, T., Pequegnat, W., Moore, J., Parker, C., Strader, L., Green, AM., ... Klausner, JD. (2013). The utility of a composite biological endpoint in HIV/STI prevention trials. AIDS and Behavior, 17(9), 2893-2901. https://doi.org/10.1007/s10461-013-0501-5

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