Impact of eGFR-based physician-visit recommendations on CKD-related clinical practices following health screening: a regression discontinuity study

BACKGROUND: Chronic kidney disease (CKD) is a global health issue, yet most patients remain undiagnosed. It is unclear whether recommendations for physician visit based on estimated glomerular filtration rate (eGFR) promote appropriate clinical practices among individuals with undiagnosed CKD. We aimed to investigate the impact of eGFR-based physician-visit recommendations on CKD-related clinical practices among health insurance beneficiaries who participated in annual health screening. METHODS: We used health screening and administrative data of Japanese adults aged 40–74 years who underwent screening between April 2022 and March 2023. Participants were mailed their results along with eGFR-based recommendations for physician visits when eGFR was below designated cutoffs. To evaluate the impact of these recommendations on the receipt of guideline-concordant CKD practices within 1 year, we used a regression discontinuity model, treating eGFR as the running variable with a cutoff of 60 mL/min/1.73 m2. Our primary outcomes were serum creatinine (sCr) measurement and CKD diagnosis, which substantiate an actual physician visit. Secondary outcomes included urinary protein assessment and nutritional guidance, both essential for appropriate CKD management. RESULTS: We included 206,222 participants (62.2% males; age 52 ± 7 years). The 60 mL/min/1.73 m2 cutoff for physician-visit recommendations was associated with modest increases in sCr measurement (3.20%; 95% confidence interval [CI], 0.73 to 5.67; p = 0.01) and CKD diagnosis (0.76%; 95% CI, 0.10 to 1.41; p = 0.02). However, no significant associations were observed for the dipstick urine protein test (0.28%; 95% CI, −1.63 to 2.20; p = 0.77), urinary protein-creatinine ratio (0.02%; 95% CI, −0.46 to 0.49; p = 0.95), and nutritional guidance (−4.30 × 10−5 %; 95% CI, −0.48 to 0.49; p = 0.99). CONCLUSIONS: The cutoff of 60 mL/min/1.73 m2 was associated with modest increases in physician visits, as substantiated by sCr measurement and CKD diagnosis. However, it was not associated with enhanced quality of CKD care, including urine testing and nutritional guidance, which are essential components of appropriate CKD management.