Determinants of virological failure and antiretroviral drug resistance in Mozambique

Objectives: The objective of this study was to inform public health actions to limit first-line ART failure and HIV drug resistance in Mozambique. Methods: This was a cross-sectional study. HIV-1-infected adults on first-line ART for at least 1 year attending routine visits in the Manhiça District Hospital, in a semi-rural area in southern Mozambique with no HIV-1 RNA monitoring available, were evaluated for clinical, socio-demographic, therapeutic, immunological and virological characteristics. Factors associated with HIV-1 RNA ≥1000 copies/mL and HIV drug resistance were determined using multivariate logistic regression. Results: The study included 334 adults on first-line ART for a median of 3 years, of which 65% (214/332) had suppressed viraemia, 11% (37/332) had low-level viraemia (HIV-1 RNA 150-999 copies/mL) and 24% (81/332) had overt virological failure (HIV-1 RNA ≥ 1000 copies/mL). HIV drug resistance was detected in 89% of subjects with virological failure, but in none with low-level viraemia. Younger age [OR=0.97 per additional year (95% CI=0.94-1.00), P=0.039], ART initiation at WHO stage III/IV [OR=2.10 (95% CI=1.23-3.57), P=0.003] and low ART adherence [OR=2.69 (95% CI=1.39-5.19), P=0.003] were associated with virological failure. Longer time on ART [OR=1.55 per additional year (95% CI=1.00-2.43), P=0.052] and illiteracy [OR=0.24 (95% CI=0.07-0.89), P=0.033] were associated with HIV drug resistance. Compared with HIV-1 RNA, clinician's judgement of ART failure, based on clinical and immunological outcomes, only achieved 29% sensitivity and misdiagnosed 1 out of every 4.5 subjects. Conclusions: Public health programmes in Mozambique should focus on early HIV diagnosis, early ART initiation and adherence support. Virological monitoring drastically improves the diagnosis of ART failure, enabling a better use of resources.