Factors associated with non-adherence to long-term highly active antiretroviral therapy: a 10 year follow-up analysis with correction for the bias induced by missing data

Objectives: The aim of this study was to identify factors associated with non-adherence over a 10 year follow-up of the APROCO-COPILOTE cohort during the maintenance phase of highly active antiretroviral therapy (HAART). Methods: Overall, 1010 patients participated in this analysis, each having had at least 12 months of follow-up after HAART initiation and at least one self-reported adherence measure available during the follow-up period (month 12-month 120). Data collection was based on clinical records and self-administered questionnaires that gathered patients' psychosocial characteristics and experience with HIV disease and treatment. First, a generalized estimating equations (GEE) model was used to identify non-adherence predictors. Secondly, a Heckman two-stage approach was used in order to account for missing data bias and to measure the extent to which this could affect the results of the first model. Results: Non-adherent behaviour was reported by 747 patients (2070 visits). After correcting for the bias due to missing data, non-adherence was independently associated with side effects, having a three times or more daily dosing regimen, experience of being at clinical stage B/C and being diagnosed as HIV-positive for < 6 months. Non-adherence was more likely among patients who were younger, had children, were born in the European Union, had depressive symptoms, consumed alcohol daily and declared a lack of support from their main partner. Adjusting for missing outcome data changed the pattern of predictors. Conclusions: Reasons for non-adherence depended on both psychosocial conditions and treatment-related characteristics. To improve long-term patient outcomes for those at risk of adherence failure, tailor-made patient-specific psychosocial interventions and regimen-based strategies with improved tolerance need to be implemented.