Viral suppression in adults on efavirenz- or dolutegravir-based antiretroviral therapy in Mopani District, South Africa.

Background: Dolutegravir- has superior viral suppression compared to efavirenz-based antiretroviral therapy (ART). However, there are limited programmatic data on suppression in rural areas of South Africa.

Objectives: We aimed to compare 6- and 12-month viral suppression of dolutegravir and efavirenz regimens and determine factors available in TIER.Net (the national electronic database for HIV and tuberculosis care) associated with suppression.

Method: We conducted a retrospective cohort study using Mopani District programme data from TIER.Net. Clients aged ≥ 15 years initiated on tenofovir-lamivudine-dolutegravir (TLD) or tenofovir-emtricitabine-efavirenz (TEE) between 01 October 2021 and 31 March 2023, with ≥ 150 days in care, were included. We analysed 6- and 12-month suppression proportions and factors associated with suppression using logistic regression.

Results: A total of 472 clients on TEE and 944 on TLD were included. Six-month viral loads were available for 47.7% (225/472) of TEE and 57.4% (542/944) of TLD clients. Six-month suppression (< 50 copies/mL) was 65.5% (355/542) for TLD and 53.8% (121/225) for TEE (P = 0.002). TLD was associated with increased odds of suppression at 6 months (adjusted odds ratio [aOR] 1.6; 95% CI: 1.1-2.2). At 12 months, viral loads were available for 60.7% (573/944) of TLD and 56.1% (265/472) of TEE clients. Twelve-month suppression (< 50 copies/mL) was 70.0% (401/573) for TLD and 68.3% (181/265) for TEE with no statistically significant differences between TEE and TLD clients. Low-level viraemia (50 copies/mL - 999 copies/mL) at 12 months was 25.0% for TLD and 20.8% for TEE.

Conclusion: TLD showed improved suppression compared to TEE at 6 but not 12 months. The high proportion of clients with low-level viraemia is concerning. All clients, regardless of regimen, need evaluation for adherence support.