Statistical Analysis
REGRESSION
All our analyses were intention-to-treat, and we assumed that participants lost to follow-up did not achieve the outcomes of interest. We prespecified our primary comparison to be the intervention group (including both forms of HIVST) vs the SOC group because we hypothesized that the effect of the intervention would be related to the frequency of PrEP clinic visits not the HIVST modality. However, we also compared the blood-based HIVST and the oral-fluid HIVST intervention groups individually with the SOC group to understand whether there were differences in testing modality.We measured the proportion of participants with each outcome by group and estimated risk differences (RDs) and 1-sided 95% CI lower bounds (LBs) using binomial regression models with identity link, adjusted for study population (eg, men in serodifferent couples, women in serodifferent couples, and women singly enrolled). In keeping with a noninferiority trial design, we prespecified a noninferiority margin of −10% and considered the intervention group noninferior to the SOC group for outcomes with a 1-sided 95% CI LB of −10% or greater.We conducted prespecified subgroup analyses and additional sensitivity analyses. Subgroup analyses were conducted to identify any marked outcome differences for (1) individuals in HIV serodifferent couples (noninferiority analysis) and (2) women singly enrolled (superiority analysis), populations we hypothesized might have different PrEP continuation needs at 12 months. For the subgroup of women singly enrolled, we prespecified a superiority analysis because we hypothesized that less frequent clinic visits and associated in-person counseling might reduce continued engagement in PrEP care. We then conducted 2 sensitivity analyses for all participants and subgroups: (1) PrEP adherence at 12 months using a protective TFV-DP threshold of 700 fmol/punch or greater, which has been commonly used in other PrEP trials and implementation studies,