Background: Adherence is important for therapy of chronic diseases, but has still not been well studied in real life in chronic hepatitis C.
Aims: To assess adherence to hepatitis C combination therapy in routine clinical practice and to identify factors associated with imperfect adherence.
Methods: This cohort study included unselected chronic hepatitis C patients initiating peginterferon α-2b plus ribavirin. 100% adherence was defined by taking all the prescribed doses of both drugs for the full initially intended duration, as declared by the patient or believed by the physician. Quality of life was assessed using the short-form health survey (SF-36) questionnaire.
Results: 1860 patients were analysed, including 72% treatment-naive, 36% genotype 2/3, 23% psychiatric, 44% drug addicts and 3% human immunodeficiency virus (HIV)-positive patients. Early treatment discontinuation occurred in 30% of patients. Overall, 38% of patients reported 100% adherence. Patient- and physician-reported adherences were discordant, with a 20–30% overestimation by physicians. HIV co-infection [odds ratio (OR) 2.52, 95% confidence interval (CI) 1.36–4.67], no drug use during follow-up (2.37, 1.30–4.31), genotype 3 (1.55, 1.20–2.00) and treatment-naive (1.32, 1.03–1.69) were associated with 100% adherence. Quality of life worsened during treatment but returned to baseline after the end of treatment.
Conclusions: Imperfect adherence to combination therapy is common in routine patients. Adherence is markedly overestimated by physicians and is associated with some patient's baseline characteristics. Knowledge of these factors might help identify patients who are most in need of intervention and plan more frequent and accurate follow-up.