Association of serum spermidine level with vascular calcification in peritoneal dialysis patients

Vascular calcification (VC) is a major predictor of mortality in patients receiving peritoneal dialysis (PD), yet reliable tools for early risk stratification remain limited. We investigated whether serum spermidine, a naturally occurring polyamine, is associated with VC in PD patients and developed an exploratory model incorporating spermidine and routine clinical variables. In a cohort of 193 PD patients, VC (n = 51) was assessed by abdominal X-ray. Univariate and multivariate logistic regression analyses were performed to identify factors associated with VC, and least absolute shrinkage and selection operator (LASSO) regression was used for variable selection and nomogram construction. Serum spermidine levels were significantly higher in patients with VC than in those without VC (median 7.02 vs. 5.63 nmol/L, p = 0.006) and remained independently associated with VC in multivariate analysis (odds ratio 1.16, 95% confidence interval 1.02-1.32, p = 0.026). The final nomogram, which included serum spermidine, age, diabetes, serum albumin, statins use, and peritonitis history, demonstrated good discrimination (area under the curve 0.795) and internal validity (C-index 0.751). These findings suggest that serum spermidine is associated with VC in PD patients and may have value as a candidate biomarker. The proposed nomogram should be considered exploratory, and its clinical utility requires validation in prospective multicenter studies.