Charlson comorbidity index and palliative performance scale predict prognosis in dialysis patients: a retrospective cohort study

Accurate prognostication in end-stage kidney disease (ESKD) is essential for informed clinical decision-making, timely palliative care integration, and aligning treatments with patient goals. Commonly used tools include the Charlson Comorbidity Index (CCI) and the Palliative Performance Scale (PPS), although their comparative predictive performance in dialysis populations remains unclear. This study aimed to evaluate and compare the prognostic accuracy of the CCI, pre-dialysis PPS, and post-dialysis PPS in predicting natural mortality among patients with ESKD receiving renal replacement therapy (RRT). This retrospective cohort study included 1,047 adult patients with ESKD who initiated hemodialysis or peritoneal dialysis at a tertiary hospital in southern Thailand between 2009 and 2022. The CCI was calculated based on diagnoses within 90 days prior to dialysis. PPS was assessed within 30 days before (pre-dialysis) and after (post-dialysis) initiation. The primary outcome was natural mortality. Predictive performance was evaluated using Kaplan–Meier survival analysis, multivariable Cox regression, and time-dependent receiver operating characteristic (ROC) curves at 30, 180, and 365 days. During a median follow-up of 5.89 years, 58.0% of patients died. The CCI effectively stratified long-term survival (median survival: 11.27 years for score < 6 vs. 3.80 years for > 8). However, for short-term prognosis, the post-dialysis PPS demonstrated superior discriminative ability. At 30 days, the continuous post-dialysis PPS model achieved a time-dependent AUC of 0.91 (95% CI 0.85–0.99), significantly outperforming the CCI (AUC 0.76). In multivariable analysis, age and post-dialysis PPS were associated with mortality. Functional recovery following dialysis initiation emerged as a critical marker of physiological resilience. The CCI and PPS offer complementary prognostic value in ESKD. While the CCI reflects the accumulated burden of disease affecting long-term survival, the post-dialysis PPS captures dynamic physiological resilience and is a superior predictor of early mortality. Incorporating post-dialysis functional assessment into routine care may enhance risk stratification, identifying high-risk patients who would benefit from early palliative care integration and goals-of-care discussions.