Attributes of primary care in relation to polypharmacy: a multicenter cross-sectional study in Japan.

Objective: To investigate the association between attributes of primary care and polypharmacy.

Design: Cross-sectional study.

Setting: A primary care practice-based research network in Japan (28 primary care clinics).

Participants: Adult outpatients filled out a standardized questionnaire.

Main Outcome Measure: Polypharmacy defined as the use of five or more concurrent prescription or over-the-counter medications.

Methods: Attributes of primary care were assessed via patient experience using the Japanese version of Primary Care Assessment Tool (JPCAT). Poisson mixed effects model was used to adjust for clustering within clinics and covariates.

Results: Data were analyzed for 544 primary care outpatients. After adjusting for patients' sociodemographic and health characteristics, the JPCAT community orientation score was found to be inversely associated with polypharmacy at the clinic level [risk ratio per 1 standard deviation increase = 0.83; 95% confidence interval (CI), 0.73-0.96; P = 0.008]. Sensitivity analyses using a different definition of polypharmacy showed results similar to those of the primary analyses.

Conclusions: We found that a higher level of community-oriented primary care is associated with a lower prevalence of polypharmacy in outpatients at the clinic level. These findings may be useful in developing community-based interventions to minimize polypharmacy.