title: The utility of a composite biological endpoint in HIV/STI prevention trials.
abstract: 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.
authors.affiliation: Research Triangle Institute, Research Triangle Park, Durham, NC, USA.
authors.forename: Tyler D
authors.initials: TD
authors.lastname: Hartwell
authors.forename: Willo
authors.initials: W
authors.lastname: Pequegnat
authors.forename: Janet L
authors.initials: JL
authors.lastname: Moore
authors.forename: Corette B
authors.initials: CB
authors.lastname: Parker
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Strader
authors.forename: Annette M
authors.initials: AM
authors.lastname: Green
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Quinn
authors.forename: Judith N
authors.initials: JN
authors.lastname: Wasserheit
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Klausner
mesh_terms: D000328:Adult; D002690:Chlamydia Infections / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006069:Gonorrhea / Q000517:prevention & control; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control*; D006558:Herpes Genitalis / Q000517:prevention & control; D006801:Humans; D015994:Incidence; D008297:Male; D015995:Prevalence; D011314:Preventive Health Services / Q000706:statistics & numerical data; D040242:Risk Reduction Behavior; D012725:Sexual Behavior / Q000706:statistics & numerical data; D015231:Sexually Transmitted Diseases, Bacterial / Q000453:epidemiology / Q000517:prevention & control*; D013587:Syphilis / Q000517:prevention & control; D014245:Trichomonas Infections / Q000517:prevention & control