Associations between the Cardiothoracic Ratio and All-cause and Cardiovascular Mortality in Patients Undergoing Peritoneal Dialysis: Fukuoka Peritoneal Dialysis Registry (F-PDR) Study

Background Patients undergoing peritoneal dialysis (PD) experience exceptionally high mortality. While the cardiothoracic ratio (CTR), a simple radiographic measure, has prognostic value in hemodialysis, its role in PD is unclear because of limited evidence. We hypothesized that a high baseline CTR is independently associated with mortality in patients undergoing PD. Methods We conducted a multicenter cohort study using data from the Fukuoka Peritoneal Dialysis Registry study. Of 1217 patients who participated in the study between 2011 and 2020, 972 with a baseline CTR were included. The CTR was categorized into sex-specific quartiles. The primary and secondary outcomes were all-cause and cardiovascular mortality, respectively. We used multivariable Cox proportional hazards models to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). Results During a median follow-up of 731 days, 156 (16.0%) patients died, including 54 (5.6%) from cardiovascular causes. After multivariable adjustment, patients in the highest CTR quartile had significantly elevated risks of all-cause mortality (HR, 3.01; 95% CI, 1.85–5.04) and cardiovascular mortality (HR, 5.44; 95% CI, 2.17–13.59) compared with the lowest quartile. Each 1-standard deviation increase in the CTR was also associated with a higher risk of all-cause (HR, 1.40; 95% CI, 1.20–1.65) and cardiovascular mortality (HR, 1.68; 95% CI, 1.27–2.23). The findings were consistent in sensitivity analyses. Conclusions An elevated baseline CTR is an independent predictor of all-cause and cardiovascular mortality in patients undergoing PD. This simple, readily available measure may be a useful tool for risk stratification in this high-risk population.