Incomplete medication adherence of chronically ill patients in German primary care.

BACKGROUND: Incomplete medication adherence is a major problem in health care worldwide. Patients who adhere to medical treatment have a better prognosis and create fewer costs.

OBJECTIVE: To assess the degree of incomplete adherence of chronically ill routine primary care patients in a German setting and analyze the association between incomplete medication adherence, as well as clinical and sociodemographic patient characteristics.

METHODS: In a cross-sectional survey, chronically ill patients were asked to assess their adherence in primary care retrospectively using the Medication Adherence Report Scale (MARS-D) questionnaire. To investigate the association of incomplete adherence with sociodemographic and clinical data, univariate and multivariate analyses were conducted.

RESULTS: In total, 62.1% of 190 patients were categorized as incompletely adherent. The mean MARS-D score was 23.5 (standard deviation = 2.7). Analyses revealed no statistically significant associations at P < 0.05 between degree of adherence and patient characteristics. The total explained variance amounted to 11.8% (Nagelkerke's R(2) = 0.118) in the multivariate analysis.

CONCLUSION: Previously reported results regarding associations of sociodemographic and clinical data with incomplete medication adherence could not be confirmed for this sample of chronically ill patients. In order to be able to provide guidelines for the reduction of incomplete medication adherence in German primary care, further research is needed.