Factors associated with medication nonadherence in patients with COPD

Study objectives: To identify the predictors of medication adherence in patients with COPD and contrast the health beliefs, experiences, and behaviors of COPD patients self-reporting good adherence with those of patients reporting suboptimal adherence to their medications. Design: Cross-sectional self-administered questionnaire. Setting: Ambulatory care. Participants: Patients with chronic respiratory ailments identified through respiratory support groups and from a pulmonary rehabilitation database. Measurements and results: A 30-item questionnaire comprising items pertaining to health beliefs, experiences, and behaviors along with a valid self-reported measure of adherence-the medication adherence report scale (MARS)-was administered to 525 ambulatory patients with chronic lung conditions. A total of 276 usable responses were received (52.6%). The mean age of the respondents was 71 years, and there were slightly more male patients (54.4%). COPD was the underlying disease condition in 90.6% of the respondents; two thirds of the respondents had comorbid conditions. The respiratory condition was managed by both general practitioners and respiratory specialists in 61.2% of cases. One third of the respondents self-reported complementary and alternative medicine use. The mean score (+/- SD) on the MARS among the respondents was 23.37 +/- 2.09. One hundred two patients self-reported perfect adherence on the MARS. Differences in knowledge about the illness and treatment, faith in and satisfaction with the treatment and doctors, concerns about the treatment, and intentional and unintentional deviations from the recommended treatment were detected between the adherent and less adherent groups. In multivariate analysis, "I vary my recommended management based on how I am feeling" and "I get confused about my medications" were found to be significant independent predictors of nonadherence. Conclusions: Patients' acceptance of the disease process and recommended treatment, knowledge about and faith in the treatment, effective patient-clinician interaction, and routinization of drug therapy are critical for optimal medication adherence in patients with COPD.