Sustained virological response and drug resistance among female sex workers living with HIV on antiretroviral therapy in Kampala, Uganda: a cross-sectional study

Objectives We assessed the prevalence and risk factors associated with virological failure among female sex workers living with HIV on antiretroviral therapy (ART) in Kampala, Uganda. Methods We conducted a cross-sectional study between January 2015 and December 2016 using routinely collected data at a research clinic providing services to women at high risk of STIs including HIV. Plasma samples were tested for viral load from HIV-seropositive women aged >= 18 years who had been on ART for at least 6 months and had received adherence counselling. Samples from women with virological failure (>= 1000 copies/mL) were tested for HIV drug resistance by population-based sequencing. We used logistic regression to identify factors associated with virological failure. Results Of 584 women, 432 (74%) with a mean age of 32 (SD 6.5) were assessed, and 38 (9%) were found to have virological failure. HIV resistance testing was available for 78% (28/38), of whom 82.1% (23/28) had at least one major drug resistance mutation (DRM), most frequently M184V (70%, 16/23) and K103N (65%, 15/23). In multivariable analysis, virological failure was associated with participant age 18-24 (adjusted OR (aOR)=5.3, 95% CI 1.6 to 17.9), self-reported ART non-adherence (aOR=2.6, 95% CI 1.2 to 5.8) and baseline CD4+ T-cell count <= 350 cells/mm(3) (aOR=3.1, 95% CI 1.4 to 7.0). Conclusions A relatively low prevalence of virological failure but high rate of DRM was found in this population at high risk of transmission. Younger age, self-reported ART non-adherence and low CD4+ T-cell count on ART initiation were associated with increased risk of virological failure.