Associations of primary care structures with polypharmacy and patient-reported indicators in patients with complex multimorbidity: a multicentre cross-sectional study in Japan

Objectives Evidence supporting the effects of primary care structures on the quality of care for patients with complex multimorbidity, which is one of the most important challenges facing primary care, is scarce internationally. This study aimed to examine the associations of the types of primary care facilities with polypharmacy and patient-reported indicators in patients with complex multimorbidity, with a focus on differences between community clinics and hospitals. Design Multicentre cross-sectional study. Setting A total of 25 primary care facilities (19 community clinics and 6 small- and medium-sized hospitals). Participants Adult outpatients with complex multimorbidity, which was defined as the co-occurrence of three or more chronic conditions affecting three or more different body systems within one person. Primary outcome measure Polypharmacy, the Patient-Reported Experience Measure using the Japanese version of Primary Care Assessment Tool Short Form (JPCAT-SF) and the Patient-Reported Outcome Measure using self-rated health status (SRH). Results Data were analysed for 492 patients with complex multimorbidity. After adjustment for possible confounders and clustering within facilities, clinic-based primary care practices were significantly associated with a lower prevalence of polypharmacy, higher JPCAT-SF scores in coordination and community orientation, and a lower prevalence of poor or fair SRH compared with hospital-based primary care practices. In contrast, the JPCAT-SF score in first contact was significantly lower in clinic-based practices. The associations between the types of primary care facilities and JPCAT-SF scores in longitudinality and comprehensiveness were not statistically significant. Conclusions Clinic-based primary care practices were associated with a lower prevalence of polypharmacy, better patient experience of coordination and community orientation, and better SRH in patients with complex multimorbidity compared with hospital-based primary care practices. In the primary care setting, small and tight teams may improve the quality of care for patients with complex multimorbidity.