AFYA 1 LONG TERM STUDY (2018-2019)

Durability of effects from short-term economic incentives for clinic attendance among HIV positive adults in Shinyanga, Tanzania: long-term follow-up of a randomized controlled trial


Background: Conditional economic incentives are shown to improve medication adherence; however, any long-term harms or benefits from these short-term interventions remain largely unknown. We evaluated 2- to 3-year outcomes from a 6-month incentive program.

Methods: We traced former participants in a trial that randomized 800 food-insecure adults starting HIV treatment in Tanzania to receive usual care (control) or to additionally receive cash or food transfers (~$11/month) for ≤6 months, conditional on appointment attendance ( NCT01957917). The primary intention-to-treat analysis estimated 24- and 36-month marginal risk differences (RD) in retention in care and all-cause mortality comparing combined incentive arms to the control, with multiple imputation for missing outcomes. We also estimated mortality hazard ratios (HR) from time-stratified Cox regression.

Results: From March 3, 2018 to September 19, 2019, we determined 36-month retention and mortality statuses for 737 (92%) and 700 (88%) participants, respectively. Overall, approximately 660 (83%) participants were in care at 36 months while 43 (5%) had died. There were no group differences in retention at 24 months (86.5% intervention vs. 84.4% control, RD=2.1, 95% CI -5.2–9.3) or 36 months (83.3% vs. 77.8%, RD=5.6, -2.7–13.8), nor in mortality at either time point. The intervention group had a lower rate of death during the first 18 months (HR=0.27, 0.10–0.74); mortality was similar thereafter (HR=1.13, 0.33–3.79).

Conclusions: These findings confirm that incentives are a safe and effective tool to promote short-term adherence and potentially avert early deaths at the critical time of HIV treatment initiation. Complementary strategies are recommended to sustain lifelong adherence.