Effect of facility- versus community-based HIV testing services on the diagnosis of advanced HIV disease in Uganda: a quasi-experimental study

Advanced HIV disease (AHD) at first diagnosis remains a significant barrier to HIV epidemic control. We evaluated whether health facility-based or community-based HIV testing services (HTS) better impact the yield of AHD at diagnosis among newly diagnosed people with HIV (PWH) in rural eastern Uganda. We designed a quasi-experimental study and applied instrumental variable analysis, a causal inference methodology, to compare the effect of facility-based HTS versus community-based HTS on the yield of AHD at diagnosis among newly diagnosed PWH. The exposure was HTS comparing community-based versus facility-based, and the outcome was AHD at diagnosis, defined as CD4 < 200 cells/µL or WHO clinical stage 3 or 4 disease at baseline. The instrumental variable was the HTS access radius that reflects the HTS geographical coverage for each health facility. The instrumental variable ensured the categorization of health facilities as offering HTS within a 5 km radius only or both within and beyond 5 km. The relevance of the instrumental variable was assessed using the F-statistic and independence from measured covariates. We used a two-stage residual inclusion approach to estimate the effect of HTS on AHD at diagnosis. Causal effect was reported as an odds ratio (OR) and 95% confidence interval (CI). Of 1,233 participants included in the analysis, AHD prevalence was 1.9% (24/1,233). The instrumental variable was strongly correlated with HTS (First-stage F-statistic = 28.05, p < 0.0001) and uncorrelated with AHD and all measured covariates. Facility-based HTS has no significant effect on AHD at diagnosis compared to community-based HTS (OR 1.20, 95% CI 0.49–2.90). Persons with AHD at diagnosis are a minority. Facility- and community-based HTS do not differ in identifying AHD among newly diagnosed PWH, but moderate effects cannot be excluded. These findings support efforts to implement both strategies for HIV testing to reach and test persons with advanced HIV.