Association between specialist distribution and peritoneal dialysis use in Japan: An ecological study

BackgroundPeritoneal dialysis (PD) is a cost-effective, patient-centered kidney replacement therapy. However, its use in Japan remains limited. This study assessed regional variations in PD use and its association with involved specialists.MethodsThis cross-sectional study was conducted using data from the National Database Open Data Japan for the fiscal year 2022. PD use was evaluated using standardized claim ratios (SCRs), calculated from insurance claims for home PD management fee and PD catheter insertion. PD use was assessed among three types of specialists: Board Certified Nephrologists of the Japanese Society of Nephrology (JSN nephrologists), Fellows of the Japanese Society for Dialysis Therapy (JSDT fellows), and Certified Physicians of the Japanese Society for Peritoneal Dialysis (JSPD physicians). Associations between the number of specialists and SCRs for PD use were assessed using multivariable-adjusted negative binomial regression models.ResultsPD use varied across regions. SCRs ranged from 34.0 to 264.6 for home PD management fee and from 35.1 to 239.7 for PD catheter insertion. Each additional JSDT fellow per 100,000 population was associated with a 1.11-fold increase in SCR for home PD management fee (ß = 0.10; 95% CI: 0.02 to 0.19; p = 0.02) and a 1.13-fold increase in SCR for PD catheter insertion (ß = 0.12; 95% CI: 0.02 to 0.21; p = 0.02). Similar associations were observed for JSPD physicians, but not for JSN nephrologists.ConclusionRegional disparities in PD use exist in Japan. A higher number of specialists in PD care was associated with greater PD use.