Self-reported non-adherence to ART and virological outcome in a multiclinic UK study

Adherence is of fundamental importance to ART success. We examined the association of self-reported non-adherence with demographic factors, health and behaviour issues, and virological outcome, in a multi-clinic study. Seven hundred and seventy-eight HIV patients in five clinics in London and Brighton completed a questionnaire on adherence and HIV/health issues at baseline in 2005/6. For 486 subjects taking ART, non-adherence in the past week was defined as: (A)>or=1 dose missed or taken incorrectly (wrong time/circumstances); (B)>or=1 dose missed; (C)>or=2 doses missed. Questionnaire data were matched with routine treatment and virology data for consenting subjects (61.4%). We assessed four virological outcomes in 307 of 486 patients: (i) VL>50c/mL using latest VL at the questionnaire and excluding patients starting HAART<24 weeks ago; (ii) VL>50c/mL using the first VL from 6 to 12 months post-questionnaire; (iii) any VL>50c/mL from 6 to 12 months post-questionnaire; (iv) among patients with VL<50c/mL at questionnaire, time to first subsequent VL>50c/mL over two years follow up. Non-adherence was reported by 278 (57.2%), 102 (21.0%) and 49 (10.1%) of 486 patients, for definitions A, B and C, respectively. Non-adherence declined markedly with older age, and tended to be more commonly reported by Black patients, those born outside the UK, those with greater psychological symptoms and those with suicidal thoughts. There was a weaker association with physical symptoms and no association with gender/sexuality, education, unemployment, or risk behaviour (p>0.1). In logistic regression analyses, younger age, non-UK birth and psychological variables were independent predictors of non-adherence [e.g., for non-adherence B: odds ratios (95% CI) were 0.95 (0.92, 0.98) for every year older age; 1.6 (1.0, 2.5) for non-UK born; 2.3 (1.5, 3.7) for suicidal thoughts]. Non-adherence was associated with poorer virological outcome; the most consistent association was for definition C. Among 255 patients with VL<50c/mL at baseline, non-adherence definition C was independently associated with subsequent VL>50c/mL [adjusted hazard ratio (95% CI) 3.2 (1.5, 7.2)]. Non-UK birth and psychological symptoms predicted non-adherence, but the most striking association was with younger age. Age should be an important consideration in clinical strategies to minimise non-adherence and in decisions regarding ART initiation. A simple measure of non-adherence can identify patients at risk of poorer virological outcome.