The association between adherence to antiretroviral therapy and viral suppression under dolutegravir-based regimens: an observational cohort study from Uganda.

Abstract

Millions of people living with HIV (PLWH) take oral antiretroviral therapy (ART), which requires a lifetime of consistent medication adherence. The relationship between adherence and poor HIV outcomes is well documented. Newer ART regimens that include dolutegravir (DTG) could be more forgiving, but empirical evidence on the relationship between adherence and viral suppression under DTG is only emerging. In this observational cohort study (secondary analysis of data from a randomized trial), we used data from 313 ART clients from a large HIV clinic in Kampala, Uganda. Over the 4-year study period (January 2018-January 2022), 91% switched from non-DTG regimens to DTG regimens. We measured adherence using Medication Event Monitoring Systems-caps and extracted prescription information and viral load measures from electronic health records. We estimated unadjusted linear regressions and adjusted models that included individual and time fixed-effects. Under non-DTG regimens, 96% of participants were virally suppressed (defined as viral load < 200 copies/ml) when adherence was 90% or higher in the 3 months before viral load measurement. Viral suppression was 32 percentage points lower when adherence was between 0% and 49% (95% CI -0.44, -0.20, p < 0.01), 12 percentage points lower when adherence was between 50% and 79% (95% CI -0.23, -0.02, p < 0.01), and not significantly different when adherence was between 80% and 89% (effect of 0.00, 95% CI -0.06, 0.07, p = 0.81). In contrast, for participants taking DTG, there was no statistically significant difference in viral suppression among any of the four adherence levels; more than 95% were virally suppressed at each adherence level. On average, switching to DTG increased viral suppression by 6 percentage points in our adjusted models (95% CI 0.00, 0.13, p = 0.03). There was no significant association between adherence levels and viral suppression among PLWH taking DTG regimens, suggesting a high degree of forgiveness for missed doses. The use of DTG should be prioritized over older regimens, particularly for those with low adherence. NCT03494777.