Screening and Enrollment by Sex in Human Immunodeficiency Virus Clinical Trials in the United States

Background Women are underrepresented in human immunodeficiency virus (HIV) research in the United States. To determine if women screening for HIV clinical trials enrolled at lower rates than men, we performed a retrospective, cross-trial analysis. Methods We conducted an analysis of screening and enrollment during 2003–2013 to 31 clinical trials at 99 AIDS Clinical Trials Group network research sites in the United States. Random-effects meta regression estimated whether sex differences in not enrolling (“screen out”) varied by various individual, trial, or site characteristics. Results Of 10 744 persons screened, 18.9% were women. The percentages of women and men who screened out were 27.9% and 26.5%, respectively (P = .19); this small difference did not significantly vary by race, ethnicity, or age group. Most common reasons for screening out were not meeting eligibility criteria (30–35%) and opting out (23%), and these did not differ by sex. Trial and research site characteristics associated with variable screen-out by sex included HIV research domain and type of hemoglobin eligibility criterion, but individual associations did not persist after adjustment for multiple testing. Conclusions In the absence of evidence of significantly higher trial screen-out for women, approaching more women to screen may increase female representation in HIV trials.