Multimorbidity and patient-reported diagnostic errors in the primary care setting: multicentre cross-sectional study in Japan

Objectives There is lack of evidence for the association between multimorbidity and diagnostic errors. Information on diagnostic errors from patients' perspectives is crucial to improve the diagnostic process. In this study, we aimed to investigate patient-reported diagnostic errors and to examine the relationship between multimorbidity and patient-reported diagnostic errors in the primary care setting. Design Multicentre cross-sectional study. Setting A primary care practice-based research network in Japan (25 primary care facilities). Participants Adult outpatients filled out a standardised questionnaire. Primary outcome measure Patient-reported diagnostic errors. Results Data collected from 1474 primary care outpatients were analysed. The number of participants who reported diagnostic errors was 57 (3.9%). Most of the missed diagnoses were common conditions in primary care, such as cancer, dermatitis and hypertension. After adjustment for possible confounders and clustering within facilities, multimorbidity was positively associated with patient-reported diagnostic errors (adjusted OR=1.83, 95% CI 1.01 to 3.31). The results of the sensitivity analysis were consistent with those of the primary analysis. Conclusions The present study showed a lower proportion of patients reporting experiences of diagnostic errors in primary care than those reported in previous studies in other countries. However, patients with multimorbidity are more likely to report diagnostic errors in primary care; thus, further research is necessary to improve the diagnostic process for patients with multimorbidity.