Drug resistance mutations after the first 12 months on antiretroviral therapy and determinants of virological failure in Rwanda.

OBJECTIVE: To evaluate HIV drug resistance (HIVDR) and determinants of virological failure in a large cohort of patients receiving first-line tenofovir-based antiretroviral therapy (ART) regimens.

METHODS: A nationwide retrospective cohort from 42 health facilities was assessed for virological failure and development of HIVDR mutations. Data were collected at ART initiation and at 12 months of ART on patients with available HIV-1 viral load (VL) and ART adherence measurements. HIV resistance genotyping was performed on patients with VL ≥1000 copies/ml. Multiple logistic regression was used to determine factors associated with treatment failure.

RESULTS: Of 828 patients, 66% were women, and the median age was 37 years. Of the 597 patients from whom blood samples were collected, 86.9% were virologically suppressed, while 11.9% were not. Virological failure was strongly associated with age <25 years (adjusted odds ratio [aOR]: 6.4; 95% confidence interval [CI]: 3.2-12.9), low adherence (aOR: 2.87; 95% CI: 1.5-5.0) and baseline CD4 counts <200 cells/μl (aOR 3.4; 95% CI: 1.9-6.2). Overall, 9.1% of all patients on ART had drug resistance mutations after 1 year of ART; 27% of the patients who failed treatment had no evidence of HIVDR mutations. HIVDR mutations were not observed in patients on the recommended second-line ART regimen in Rwanda.

CONCLUSIONS: The last step of the UNAIDS 90-90-90 target appears within grasp, with some viral failures still due to non-adherence. Nonetheless, youth and late initiators are at higher risk of virological failure. Youth-focused programmes could help prevent further drug HIVDR development.