Assessment of inter-rater agreement between physicians and their patients regarding medication adherence in a clinical questionnaire study

While it is important to treat lifestyle-related diseases for the primary and secondary prevention of cardiovascular diseases, medication adherence is still poor. Although various causes of poor adherence have been reported, the differences between physicians and their patients regarding the recognition of medication adherence have not been well-investigated. We administered a questionnaire about medication adherence to 300 outpatients and their 23 cardiologists at the Department of Cardiology, Fukuoka University Hospital. The questionnaires for patients and physicians included acceptable total number of drug doses and dosing schedule, forgetting to take the medicine, and dose-reduction or -increase based on self-judgement. The patients were 70.6 ± 12.3 years old and 61.0% (n = 183) were male. Patients reported that it was acceptable to receive 0–5 doses twice daily. The patients were divided into two groups: an agreement group, in which physicians and their patients had the same answer to the question regarding forgetting medication (203 cases; 67.7%), and a disagreement group (97 cases; 32.3%). Overall, the inter-rater agreement between physicians and patients with regard to forgetting medication was significant, but slight (κ coefficient = 0.12). In a multivariate analysis, absence of hypertension [odds ratio (OR): 0.21, 95% confidence interval (CI): 0.09–0.50, P < .001), β-blocker usage (OR: 1.86, 95% CI: 1.11–3.12, P = .02), and biguanide usage (OR: 4.04, 95% CI: 1.43–11.41, P = .01) were independent predictors of disagreement with regard to forgetting medication. The inter-rater agreement between physicians and patients with regard to medication adherence was slight. An increase in inter-rater agreement should improve medication adherence.