Non-compliance with digoxin in patients with heart failure and/or atrial fibrillation: a systematic review and meta-analysis of observational studies.

Digoxin is highly potent and efficacious for treatment of heart failure (HF) and/or atrial fibrillation (AF) yet compliance is often poor. To examine prevalence rates of non-compliance with digoxin; variations between clinical settings, types of non-compliance and methods of detection; and potential factors influencing non-compliance with digoxin. This was a systematic review and meta-analysis of prospective observational studies of non-compliance with digoxin in patients with HF and/or AF, published in English. The studies were identified through these bibliographic databases: MEDLINE, EMBASE, CINAHL, IPA and Cochrane CENTRAL. Subgroup analysis examined the influence of clinical settings, types of non-compliance and methods of detection. Ten studies met the inclusion criteria, comprising 1841 patients with HF and/or AF. The corresponding prevalence rates of non-compliance for outpatients, after hospital discharge and inpatients were 43.1% (interquartile range [IQR] 29-48%), 25% (95% confidence interval [CI] 12-37%) and 4.5%, respectively. In patients with HF and AF co-morbidities, the prevalence rate of non-compliance with digoxin was 38.7% (IQR 27-46%); the corresponding prevalence rates of overdosing and underdosing were 33.04% (IQR 22-49%) and 33.8% (95% CI 25-42%), respectively. Rates varied depending on the methods of detecting non-compliance. Regularity of prescribed dose, diuretic use, coronary artery bypass, implantable cardioverter-defibrillator, number of office visits and pill boxes demonstrated strong associations with non-compliance with digoxin. Non-compliance with digoxin is prevalent among patients with HF and/or AF. A better understanding of the factors influencing compliance and improved intervention strategies are necessary to increase digoxin compliance.