Association between the Naples Prognostic Score and the Charlson Comorbidity Index in peritoneal dialysis patients

This study aimed to investigate the association between the Naples Prognostic Score (NPS) and the Charlson Comorbidity Index (CCI) and to evaluate the relationship of NPS with inflammatory and nutritional status in patients undergoing peritoneal dialysis (PD). A total of 59 PD patients (mean age 41.8 ± 18.1 years, 30 females) who received PD between 2020 and 2025 were retrospectively analyzed. NPS was calculated using serum albumin, total cholesterol, neutrophil-to-lymphocyte ratio (NLR), and lymphocyte-to-monocyte ratio (LMR), and patients were classified into NPS groups. Comorbidity burden was assessed using CCI. Group comparisons and correlation analyses were performed to determine associations between NPS, clinical variables, laboratory parameters, and CCI. The mean NPS and CCI were 2.80 ± 1.21 and 3.71 ± 2.21, respectively. Patients with higher NPS had significantly longer dialysis duration and elevated markers of systemic inflammation, including C-reactive protein, neutrophils, and monocytes, whereas they showed lower lymphocyte counts, lymphocyte-to-monocyte ratio, LDL cholesterol, and total cholesterol (all p < 0.05). NPS correlated positively with CRP and NLR and negatively with albumin, total protein, lymphocyte count, total cholesterol, and LMR (all p < 0.05). No significant association was found between NPS and CCI in group comparisons or correlation analyses. While NPS is significantly associated with systemic inflammation and impaired nutritional status in PD patients, it does not reflect comorbidity burden as measured by CCI. These findings suggest that despite its retrospective design, NPS may serve as a practical, laboratory-based marker of inflammatory and nutritional derangements in PD, distinct from chronic comorbidity indices.