Prevalence of vitamin D deficiency in Thai patients receiving various modalities of renal replacement therapy

Background: Vitamin D status of Thai patients receiving renal replacement therapy (RRT) is incompletely known. Objectives: To determine the prevalence of vitamin D deficiency or insufficiency in adult Thai patients receiving various RRT modalities, and factors associated with low vitamin D levels. Methods: In this retrospective, observational, single-center, cross-sectional study, we evaluated dialysis-related laboratory test variables from 111 patients receiving RRT. Serum 25-hydroxyvitamin D concentration [ 25(OH) D] <15 ng/mL was defined as deficiency, and 15-30 ng/mL as insufficiency. Results: Low vitamin D levels were identified in 100% patients receiving peritoneal dialysis (PD; 81% deficient, 19% insufficient), 94% patients receiving online-hemodiafiltration (OL-HDF; 50% deficient, 44% insufficient), and 100% patients with kidney transplants (KT; 55% deficient, 45% insufficient). PD patients showed significantly lower serum [ 25(OH) D] than OL-HDF or KT patients (10.5 +/- 5.9 vs 17.7 +/- 8.5 vs 15.4 +/- 6.1 ng/mL respectively, P < 0.001). OL-HDF patients with vitamin D deficiency had significantly lower vascular access flow than those without deficiency (833 +/- 365 vs 1239 +/- 385 mL/min, P = 0.008). KT recipients from deceased donors had lower serum [ 25(OH) D] than KT recipients from living, related donors (13.7 +/- 6.0 vs 17.5 +/- 5.7 ng/mL, P = 0.045). Multiple logistic regression found treatment by renin-angiotensin system blockade, serum triglyceride, and intact parathyroid hormone levels significantly associated with vitamin D deficiency after adjusting for sex, and serum calcium, phosphate, and albumin levels. Conclusions: Nearly 100% patients receiving RRT had vitamin D deficiency or insufficiency, and RRT modalities might be related.