Estimating the mortality risk correcting for high loss to follow-up among female sex workers with HIV in Durban, South Africa, 2018-2021

This study assesses risk factors of loss to follow-up (LTFU) and estimates mortality risk among female sex workers (FSW) with HIV in Durban, South Africa, in 2018–2021. We used data from the Siyaphambili trial, which evaluated strategies for improved viral suppression. FSW with HIV aged ≥ 18 years with viral load ≥ 50 copies/mL were followed up for 18 months. LTFU was defined as absence from study or intervention visits for 6 months. We traced LTFU participants by calling/in-person visit attempts to ascertain their vital status. We used Cox regression to determine risk factors of LTFU and inverse probability of tracing weights to correct mortality risk. Of 777 participants, 10 (1.3%) had died and 578 (74.4%) were initially LTFU. Among those LTFU, 36.3% (210/578) were traced successfully, with 6 additional deaths ascertained. Recent physical and sexual violence, and non-viral suppression were associated with increased LTFU. The unweighted and weighted 18-month mortality risks were 2.4% (95% CI: 0.8%−3.9%) and 3.7% (95% CI: 1.8%−5.9%), respectively. LTFU is common among FSW with HIV in South Africa with additional investigation of vital status demonstrating under-ascertained mortality. These data suggest the need for comprehensively addressing risks for mortality among FSW.