Adherence to prescribed oral medication in adult patients undergoing chronic hemodialysis: A critical review of the literature

OBJECTIVE: Poor adherence to complex multimodal therapies is a widely recognized problem in the daily care of dialysis patients, contributing to excess morbidity and mortality of this population. While a few studies have been devoted to understanding patient nonadherence, their results were somewhat controversial. The goals of this review are to quantify nonadherence to certain oral medications, to raise awareness of factors that may cause problems in a patient's adherence to this treatment, and to describe strategies that may be used to improve adherence to prescribed pharmacotherapy. METHODS: A systematic literature review in the MEDLINE and PubMed database (1971-2008) was performed. Quantitative studies, which accurately indicated the total percentages of nonadherence to oral medication in adult patients receiving chronic hemodialysis, were identified. RESULTS: A total of 19 studies fulfilled the search criteria. Rates of nonadherence to the oral medication ranged from 3 - 80%. More than half of the included studies reported nonadherence rates of ≥ 50% (mean 67%). The use of phosphate binding therapy was the prevalent surveyed oral medication. Self reports, structured interviews, and predialysis serum phosphate levels were the most frequent assessment tools used to record adherence rates. Limitations of the reviewed studies included small patient cohorts, inconsistent definitions of adherence, and a lack of standardized methods for measuring nonadherence. CONCLUSIONS: Nonadherence to oral medication in hemodialysis patients is still an underestimated, but life-threatening behaviour.