Abstract: Objective  To investigate the association between 25-hydroxyvitamin D3 [25(OH)D3] and chronic kidney disease-associated pruritus (CKD-aP) in patients on maintenance hemodialysis (MHD) or peritoneal dialysis (PD), and the predictive value of 25(OH)D3 level for CKD-aP in dialysis patients. Methods  In this single-center, cross-sectional study, patients with MHD, or PD treatment from 1 January 2022 to 31 December 2022 in the Zhongda Hospital, affiliated with Southeast University were selected as subjects. Based on the absence of CKD-aP, the patients were divided into the non-pruritus and pruritus groups, then compare the clinical data and 25(OH)D3 level between the two groups. The pruritus group further divided into mild and moderate-to-severe pruritus based on the pruritus score. Then we compared the 25(OH)D3 levels in the general population, MHD, and PD patients in different itching severity groups. The ROC curve was used to analyze the clinical value of 25(OH)D3 in predicting the occurrence of CKD-aP in dialysis patients.  Results  A total of 331 dialysis patients were included, including 238 patients with MHD and 93 patients with PD. The prevalence of CKD-aP was 56.5%, 58.4% and 51.6%, respectively. The 25(OH)D3 in the pruritus group of MHD and PD patients was lower than that in the non-pruritus group (MHD: 13.490 (10.140, 17.980) vs. 18.900 (10.910, 24.630), Z=-3.538, P<0.001; PD: 7.215 (4.843, 11.875) vs. 12.090 (6.630, 15.240), Z=-3.075, P=0.002). Further analysis showed that There were statistically differences in 25(OH)D3 among no pruritus group, mild pruritus group, and moderate to severe pruritus group (total population: H=28.823 P<0.001; MHD: H=25.137 P<0.001; PD: H=12.228 P=0.002). 25(OH)D3 decreased with the increase of pruritus in the total population and MHD patients (P<0.05). The 25(OH)D3 in the non-pruritus group was higher than that in the mild pruritus group (P=0.015) and the moderate-to-severe pruritus group (P=0.003), and there was no significant difference in 25(OH)D3 between the mild pruritus group and the moderate-to-severe pruritus group (P=0.081). The results of multivariate logistic regression analysis showed that white blood cell count (OR=1.257, 95% CI: 1.033～1.529, P=0.022), serum phosphorus (OR=2.277, 95% CI: 1.215～4.268, P=0.010), parathyroid hormone (OR=1.002, 95% CI: 1.000～1.003, P=0.018), β2-microglobulin (OR=1.039, 95% CI: 1.007～1.073, P=0.017) were risk factors for CKD-aP in MHD patients, and serum phosphorus (OR=4.613, 95% CI: 1.354～15.719,P=0.015) and hypersensitive C-reactive protein (OR=1.192, 95% CI: 1.019～1.395, P=0.028) were risk factors for CKD-aP in PD patients. 25(OH)D3 was a protective factor for CKD-aP in patients with MHD and PD (MHD: OR=0.937, 95% CI: 0.901～0.975, P=0.001. PD: OR=0.909, 95% CI: 0.830～0.995, P=0.038). The ROC curve showed that the predicted AUC was 0.635 when the 25(OH)D3<18.835 ng/ml in MHD patients and 0.685 when the 25(OH)D3<10.545 ng/ml in PD patients.  Conclusions  Lower 25(OH)D3 may play an important role in CKD-aP in dialysis patients. Moreover, 25(OH)D3 level has certain clinical value in predicting the occurrence of CKD-aP in dialysis patients.

Key words: 25(OH)D3, Chronic kidney disease-associated pruritus, Maintenance hemodialysis, Peritoneal dialysis