Initiation of Dolutegravir Versus Efavirenz on Viral Suppression and Retention at 6 months: A Regression Discontinuity Design.

BACKGROUND

In 2019, South Africa's Antiretroviral Therapy (ART) Treatment Guidelines replaced efavirenz with dolutegravir in first-line ART.

SETTING

We assessed the impact of this national guideline change on retention and viral suppression in the Themba Lethu Clinical Cohort, Johannesburg, South Africa. We applied a regression discontinuity design in a prospective cohort study of 1654 adults living with HIV initiating first-line ART within 12 months (±12 months) of the guideline change.

METHODS

We compared outcomes in individuals presenting just before and after the guideline change and estimated intention-to-treat effects on initiating a dolutegravir- vs efavirenz-based regimen. Primary outcomes were retention and viral suppression. Participants were defined as retained in care if a visit took place within ±3 months of the 6-month end point. Viral suppression was defined as having a viral load ≤1000 copies/mL 3 months before and up to 6 months after the 6-month end point.

RESULTS

The 2019 guideline change led to an increase in uptake of dolutegravir. We noted a 26.6 percentage point increase in the proportion initiating dolutegravir [95% Confidence Interval (CI): 14.1 to 38.6]. We saw a small increase in viral suppression [Risk Difference (RD): 7.4 percentage points; 95% CI: -1.6 to 16.5] and no change in retention (RD: -1.7 percentage points; 95% CI: -13.9 to 10.5) at 6 months, though our findings were imprecise.

CONCLUSIONS

Our estimates suggest early uptake of the revised treatment guidelines after implementation. Despite this, there was no meaningful change in viral suppression and retention rates at 6 months.