Comparison of the Charlson Comorbidity Index and Wright-Khan Index for predicting mortality in continuous ambulatory peritoneal dialysis (CAPD) patients

Abstract

Mortality among patients receiving continuous ambulatory peritoneal dialysis (CAPD) remains substantial, and comorbidity burden is considered an important determinant of adverse outcomes. This study aimed to compare the associations of the Charlson Comorbidity Index (CCI) and Wright-Khan Index (WKI) with mortality among CAPD patients. A retrospective study was conducted using medical records of CAPD patients treated at Saiful Anwar Hospital, Malang, between August 1, 2019 and July 31, 2023. Baseline characteristics, CCI and WKI scores, and mortality status were collected. Logistic regression was performed to evaluate the association of each index with mortality, and Kaplan-Meier analysis was used to estimate survival probability across risk categories. A total of 377 CAPD patients were included, comprising 89 deaths and 288 survivors. No significant association was observed between CCI and mortality across the low-, moderate-, and high-risk categories (p=0.974, p=0.857, and p=0.845, respectively). In contrast, WKI was significantly associated with mortality in the low-risk group (odds ratio (OR)=0.40; 95% confidence interval (CI): 0.22-0.72; p=0.002) and moderate-risk group (OR=3.13; 95%CI: 1.49-6.54; p=0.002), whereas no significant association was identified in the high-risk group (p=0.664). Kaplan-Meier analysis further showed that the low-risk WKI category had the most favorable survival probability, whereas the moderate- and high-risk categories showed lower survival over follow-up. Overall, WKI showed a stronger association with mortality than CCI in this CAPD cohort and may provide greater utility for clinical risk stratification.