Community-based HIV self-testing: a cluster-randomised trial of supply-side financial incentives and time-trend analysis of linkage to antiretroviral therapy in Zimbabwe

Background HIV self-testing (HIVST) requires linkage to post-test services to maximise its benefits. We evaluated effect of supply-side incentivisation on linkage following community-based HIVST and evaluated time-trends in facility-based antiretroviral therapy (ART) initiations. Methods From August 2016 to August 2017 community-based distributors (CBDs) in 38 rural Zimbabwean communities distributed HIVST door-to-door in 19–25 day campaigns. Communities were allocated (1:1) using constrained randomisation to either one-off US$50 remuneration per CBD (non-incentive arm), or US$50 plus US$0.20 incentive per client visiting mobile-outreach services (conditional-incentive arm). The primary outcome, assessed by population survey 6 weeks later, was self-reported uptake of any clinic service, analysed with random-effects logistic regression. Separately, non-randomised difference-in-differences in monthly ART initiations were analysed for three time periods (6 months baseline; HIVST campaign; 3 months after) at public clinics with (40 clinics) and without (124 clinics) HIVST distribution in catchment area. Findings A total of 445 conditional-incentive CBDs distributed 39 205 HIVST kits (mean/CBD: 88; 95% CI: 85 to 92) and 447 non-incentive CBDs distributed 41 173 kits (mean/CBD: 93; 95% CI: 89 to 96). Survey participation was 7146/8566 (83.4%), with 3593 (50.3%) reporting self-testing including 1305 (18.3%) previously untested individuals. Use of clinic services post-HIVST was similar in conditional-incentive (1062/3698, 28.7%) and non-incentive (1075/3448, 31.2%) arms (adjusted risk ratio (aRR) 0.94, 95% CI: 0.86 to 1.03). Confirmatory testing by newly diagnosed/untreated HIVST+clients was, however, higher (conditional-incentive: 25/33, 75.8% vs non-incentive: 20/40, 50.0%: aRR: 1.59, 95% CI: 1.05 to 2.39). In total, 12 808 ART initiations occurred, with no baseline or postcampaign differences between initiation rates in HIVST versus non-HIVST clinics, but initiation rates increased from 7.31 to 9.59 initiations per month in HIVST clinics during distribution, aRR: 1.27, 95% CI 1.17 to 1.39. Conclusions Community-based HIVST campaigns achieved high testing uptake, temporally associated with increased demand for ART. Small supply-side incentives did not affect general clinic usage but may have increased confirmatory testing for newly diagnosed HIVST positive participants