Sexual behaviour among people with HIV according to self-reported antiretroviral treatment and viral load status

OBJECTIVE: To assess, among people with HIV, the association of self-reported antiretroviral treatment (ART) and viral load status with condomless sex with an HIV-serodifferent partner (CLS-D). DESIGN: Cross-sectional study of 3258 HIV-diagnosed adults in the United Kingdom, 2011–2012. METHODS: CLS-D in the past 3 months and self-reported ART/viral load were ascertained by questionnaire. Clinic-recorded viral load was documented. HIV-transmission risk sex (CLS-D-HIV-risk) was defined as CLS-D together with either not on ART or clinic-recorded viral load more than 50 copies/ml. RESULTS: Of 3178 participants diagnosed more than 3 months ago, 2746 (87.9%) were on ART, of whom self-reported viral load was ‘50 copies/ml/ or less/undetectable’ for 78.4%; ‘more than 50 copies/ml/detectable’ for 8.3%; ‘do not know/missing’ for 13.3%. CLS-D prevalence was 14.9% (326/2189), 6.4% (23/360) and 10.7% (67/629) among men who have sex with men, heterosexual men and women, respectively. Among men who have sex with men, CLS-D prevalence was 18.8% among those not on ART; 15.2% among those on ART with undetectable self-reported viral load; 9.8% among those on ART without undetectable self-reported viral load. Compared with ‘on ART with undetectable self-reported viral load’, prevalence ratios (95% confidence interval) adjusted for demographic/HIV-related factors were: 0.66 (0.45, 0.95) for ‘on ART without undetectable self-reported viral load’, and 1.08 (0.78, 1.49) for ‘not on ART’ (global P = 0.021). Among heterosexual men and women (combined), ART/self-reported viral load was not associated with CLS-D [corresponding adjusted prevalence ratios: 1.14 (0.73, 1.79) for ‘on ART without undetectable self-reported viral load’; 0.88 (0.44, 1.77) for ‘not on ART’, P = 0.77]. CLS-D-HIV-risk prevalence was 3.2% among all participants; 16.1% for ‘not on ART’; 0.6% for ‘on ART with undetectable self-reported viral load; 4.2% for ‘on ART without undetectable self-reported viral load.’ CONCLUSION: Use of ART was not associated with increased prevalence of CLS-D, and was associated with greatly reduced prevalence of HIV-transmission risk sex.