[Longitudinal study on adherence, treatment satisfaction, and effectiveness of once-daily versus twice-daily antiretroviral therapy in a Spanish cohort of HIV-infected patients (CUVA study)].

Introduction: Adherence is essential for successful antiretroviral therapy (ART), but complex dosing schedules compromise the adherence to and efficacy of this treatment. Once-daily (QD) ART simplifies treatment by lowering the dosing frequency and pill burden. The aim of this study, performed when QD regimens were still limited, was to determine the degree of adherence and patient satisfaction of QD dosing versus twice-daily dosing (BID) of ART.
Methods: Non-interventional, multicenter, longitudinal study, including initial (I), simplification (S), and rescue (R) therapies. Medical visits were performed at baseline, and at 3 and 6 months. A validated, structured questionnaire was used to assess adherence, and a visual analogical scale applied by independent observers was used to assess satisfaction.
Results: From May to December 2002, 978 patients were recruited. Average pill burden was 5 in QD vs. 6.1 in BID regimens. Undetectable viral load was achieved at 6 months in 83.7% (I), 87.5% (S), and 57.4% (R) of patients, with no significant differences between QD and BID. Adherence and satisfaction with ART were both significantly better in QD vs. BID regimens: 61.4% vs. 53.2% (P < .05) and 54.4% vs. 41.2% (P < .05), respectively. Multivariate analysis revealed the following variables to account for 1) Adherence to ART (OR; 95% CI): treatment satisfaction (1.53, 1.30-1.80), family support (1.25, 0.98-1.61), years of HIV infection (0.97, 0.94-1.003) and intravenous drug use (0.83, 0.70-0.99); 2) Satisfaction with ART: simplification group (1.70, 1.22-2.34), QD therapy (1.33, 1.13-1.56), years of HIV infection (0.95, 0.93-0.98), and CDC stage C (0.85, 0.73-1.01); and 3) Undetectable viral load: naive group (5.08, 3.14-8.22) and adherence (1.57, 1.13-2.17).
Conclusion: QD antiretroviral schedules appear to be as effective as BID regimens, with better adherence and treatment satisfaction. This may positively affect treatment efficacy at long-term.