Magnitude and Determinants of Virological Failure Among Patients >15 Years on Anti-Retroviral Therapy in Rural Lesotho Between 2015 and 2019 - A Retrospective Cohort Study.

Background: Lesotho has the second-highest HIV prevalence globally at an estimated 23%, with approximately 87% of the population between 15 and 59 years of age reported to be receiving antiretroviral treatment. There is an urgent need to increase access to effective ART due to increasing rates of first- and second-line treatment failure. Sustaining successful treatment and limiting the development of virological failure is essential, hence the need for early detection of increased viral load indicating drug resistance or rapid progression of viral replication.

Aim: The aim of the study was to determine the proportion of patients with HIV with virological failure and to identify factors associated with virological failure in two districts of Lesotho.

Methods: A retrospective cohort study was conducted in two districts (Butha-Buthe and Mokhotlong) in Lesotho. Data for all patients (age ≥15 years) in the viral load (VL) monitoring database with at least two consecutive viral load results between December 2015 and December 2019 from 22 health facilities were extracted. Descriptive data were presented using tables and figures. Bivariate and multivariate analyses were performed. A p-value < 0.05 was considered a statistically significant association.

Results: Only 4% (n = 913) of the study participants had virological failure. Longer time on treatment >65 months (AOR: 1.85 CI: 1.59-2.15) and being on second-line ART regimen (AOR: 75.23 95% CI: 75.00-99.15) were significantly (p < 0.001) associated with virological failure.

Conclusion: Virological failure among the study participants is lower compared to other settings. The study identified duration on treatment, treatment regimen as high risk for virological failure. Targeted interventions should be developed for these high-risk group individuals, with continuous monitoring of virological response and appropriate drug switching to clients to achieve improved outcomes.