First-time diagnosis and referral practices for individuals with CKD by primary care physicians: a study of electronic medical records across multiple clinics in Japan

Background Chronic kidney disease (CKD) is a major public health burden in Japan. Japanese primary care physicians (PCPs) are expected to play an important role in the early diagnosis and management of CKD, but comprehensive data on their role are limited.
Methods This observational study examined data from individuals who underwent tests for CKD diagnosis between January 2017 and September 2023 in the Japan Medical Data Survey (JAMDAS) database of primary care clinics in Japan. The primary outcome was the proportion of individuals with CKD without the registration of a CKD-related disease code. Time to CKD diagnosis and referral were also assessed.
Results Among 1,188,543 eligible individuals who underwent kidney-related laboratory tests, 183,473 (15.4%) met CKD diagnosis criteria according to the Japanese Clinical Practice Guideline for CKD. The mean (± SD) age was 77.4 ± 11.0 years, 57.1% were female, and 71.8% had CKD stage 3a. Over 98% of individuals who met CKD diagnosis criteria did not receive an insurance diagnosis code within 90 days after meeting the criteria. Among referrable individuals, 89.7% did not receive a referral within 90 days of meeting the referral criteria.
Conclusion These results suggest CKD may be underdiagnosed and under-referred in Japanese clinics. Measures should be taken to increase detection and diagnosis according to the Japanese Clinical Practice Guideline for CKD.