Identification of previously undiagnosed chronic kidney disease and analysis of preventive effects on acute kidney injury: a single-center, primary care, serial cross-sectional study in Japan

Chronic kidney disease (CKD) is often undiagnosed in primary care. While long-term risks are established, the impact of systematic screening on preventing acute kidney injury (AKI) remains unclear. This study used a serial cross-sectional design. CKD screening was conducted in 2023. We evaluated the prevalence of undiagnosed-CKD (U-CKD) and compared AKI incidence between pre-screening (2020–2023) and post-screening (2023–2026) periods. Screening identified 251 individuals with CKD (32.0%), of whom 204 (81.3%) were previously undiagnosed. Notably, 48.4% and 40.0% of patients had no documented history of eGFR or urinalysis, respectively. Following CKD screening, total AKI episodes decreased from 207 to 105 cases. Most significantly, drug-induced AKI decreased from 105 to 41 cases (61.0% reduction), with the reduction most prominent in the undiagnosed-CKD group (81.8% reduction in drug-induced AKI). Even now, more than 20 years after the concept of CKD was introduced, a large number of CKD cases remain untreated. Standardized diagnostic registration provides crucial risk awareness, leading to a significant reduction in preventable drug-induced AKI. CKD screening and clinical alerts are essential to enhance medication safety and preserve kidney function in primary care.