Adherence to prophylaxis in adult patients with severe haemophilia A.

INTRODUCTION Adherence is a cornerstone of factor VIII prophylactic treatment. Information regarding the factors with potential influence on adherence is limited, particularly in adult patients. AIM To assess adherence in adult patients with severe haemophilia A receiving prophylactic treatment in a real-life setting, and investigate the factors influencing adherence. METHODS Observational, prospective study including adult patients receiving factor VIII therapy in 15 Spanish centres. Patients recorded infusion doses on a logbook and answered various questionnaires to assess their health beliefs. Adherence rate was the percentage of infused doses over the prescribed ones. Self-perceived adherence was assessed using the VERITAS-Pro questionnaire, the psychometric properties of which were validated in the Spanish population. The relationship between adherence rate and treatment, clinical and demographic characteristics, health beliefs and perceived self-efficacy was investigated. RESULTS A total of 66 patients were followed up for 12 months. Mean adherence rate at the end of follow-up was 82.5%. Most of the study patients (n = 53, 80.3%) showed a moderate-to-high adherence rate (>70%). The VERITAS-Pro revealed a high perception of adherence. Multivariate analyses to predict treatment adherence identified the knee as a target joint and longer treatment duration as variables with significant (negative) influence on adherence. Adherence rate was not influenced by the patient's health beliefs or perceived self-efficacy. CONCLUSION Most adult patients receiving factor VIII prophylactic treatment in Spain have moderate-to-high treatment adherence. Treatment duration and the knee as a target joint are factors with a moderate negative influence on treatment adherence.