Supplementary file 1_Improvement in peritoneal dialysis exit-site infection rates in an integrated health care system in the United States.docx

The observed mean ESI rate was 1.26 (95% CI: 0.98–1.60) episodes per 100 patient-months in 2014, compared with 0.72 (95% CI: 0.42–1.07) in 2023. Each additional calendar year was associated with a 6.4% relative decrease in ESI rate (rate ratio [RR] 0.94, 95% CI 0.89–0.99, p = 0.011), corresponding to an estimated 45.1% decline in ESI rate over the study period (95% CI: 12.8–65.4%). Program size was not significantly associated with ESI rate after adjustment for calendar year (RR 0.76 per 100-patient increase, 95% CI 0.52–1.11, p = 0.15).</p>Conclusion<p>We found a significant decline in ESI rates across ten KPSC hospitals from 2014 to 2023.

This decline was not explained by growth in program size, suggesting that other factors—such as evolving infection prevention practices, staff training, or care coordination—may have contributed, though our data do not permit us to test these mechanisms directly. We encourage prospective or mechanism-specific studies to explore which factors are driving these improvements.</p>