The right combination - treatment outcomes among HIV-positive patients initiating first-line fixed-dose antiretroviral therapy in a public sector HIV clinic in Johannesburg, South Africa.

Background: Long-term antiretroviral therapy (ART) adherence is critical for achieving optimal HIV treatment outcomes. Fixed-dose combination (FDC) single-pill regimens, introduced in South Africa in April 2013, has simplified pill taking. We evaluated treatment outcomes among patients initiated on a FDC compared to a similar multi-pill ART regimen in Johannesburg, South Africa.

Methods: We conducted a retrospective cohort study of ART-naïve HIV-positive non-pregnant adult (≥18 years) patients without tuberculosis who initiated first-line ART on tenofovir and emtricitabine or lamivudine with efavirenz at Themba Lethu Clinic in Johannesburg, South Africa. We compared those initiated on a multi-pill ART regimen (3-5 pills/day; September 1, 2011-August 31, 2012) to those initiated on a FDC ART regimen (one pill/day; September 1, 2013-August 31, 2014). Treatment outcomes included attrition (combination of lost to follow-up and mortality), missed medical visits, and virologic suppression (viral load <400 copies/mL) by 12 months post-ART initiation. Cox proportional hazards models and Poisson regression were used to estimate the association between FDCs vs multiple pills and treatment outcomes.

Results: We included 3151 patients in our analysis; 2230 (70.8%) patients initiated multi-pill ART and 921 (29.2%) patients initiated on a FDC. By 12 months post-initiation, attrition (adjusted hazard ratio: 0.98; 95% CI: 0.77-1.24) was similar across regimen types (FDC vs multi-pill). Although not significant, patients on a FDC were marginally more likely to achieve viral suppression by 6 (adjusted relative rate [aRR]: 1.10; 95% CI: 0.99-1.23) and 12 months (aRR: 1.12; 95% CI: 0.92-1.36) on ART. Patients initiated on a FDC were significantly less likely to miss medical visits during the first 12 months of treatment (aRR: 0.66; 95% CI: 0.52-0.83).

Conclusion: Our results suggest FDCs may have a role to play in supporting patient adherence and medical monitoring through improved medical visit attendance. This may potentially improve treatment outcomes later on in treatment.