Relationship Between Vitamin D Levels and Inflammatory Markers in Kidney Transplant Recipients: A Retrospective Study

This study aimed to evaluate the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and hematologic inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), as well as other biochemical parameters, in patients who underwent renal transplantation due to chronic kidney disease (CKD).

This study included 304 adult renal transplant recipients followed at a single transplant center between January 2015 and June 2025. Patients were divided into 2 groups according to serum 25(OH)D levels: deficient (<20 ng/mL) and nona-deficient (≥20 ng/mL). Demographic, clinical, and laboratory data-including NLR, PLR, C-reactive protein (CRP), parathyroid hormone (PTH), erythrocyte sedimentation rate (ESR), and procalcitonin-were retrospectively reviewed. Statistical analyses were performed using the Mann-Whitney U test, chi-square test, and Pearson correlation analysis.

Vitamin D deficiency was detected in 84.2% (n = 256) of patients. Serum 25(OH)D levels were significantly and inversely correlated with PTH levels (r = -0.241, p < .001), and the deficient group had higher PTH concentrations (p = .002). Weak positive correlations were observed between 25(OH)D and both procalcitonin (r = 0.122, p = .034) and ESR (r = 0.117, p = .041). However, no significant associations were found between vitamin D levels and NLR, PLR, CRP, lipid profile, or other parameters.

Vitamin D deficiency is highly prevalent among renal transplant recipients and is significantly associated with elevated PTH levels. The weak correlations observed with inflammatory markers suggest the multifactorial nature of inflammation in this population. Routine monitoring and appropriate replacement of vitamin D may contribute to improved bone metabolism and overall health in renal transplant patients.