Abstract:

Objective To investigate the condition of lack and inadequacy of 25-hydroxyvitamin D [25(OH)D₃] in maintained hemodialysis (HD) patients with chronic kidney disease (CKD) and to analyze relationship between 25(OH)D₃ and parameters of mineral metabolism, nutrition, and dialysis adequacy indexes. Methods A total of 195 maintained HD patients with stage 5 CKD were selected. Among them, 22 patients who had recent HD in past 3-6 months did not get calcium and active vitamin D (VitD) supplement, but the other 173 patients with long-time HD, over 6 months, got calcium and/or VitD supplement. The fasting serum 25(OH)D₃ levels of patients were measured by radioimmunoassay for evaluating VitD reservation. Patients with long-time HD stopped administration of calcium and/or VitD 2 weeks before experiment. The incidences of 25(OH)D₃ inadequacy were recorded and compared. The relationships between 25(OH)D₃ and parameters of mineral metabolism (serum calcium, serum phosphorus, serum alkaline phosphatase, and intact parathyroid hormone), nutrition (serum albumin), and dialysis adequacy (urea clearance index and serum creatinine) were analyzed by multivariable Logistic regression analysis. Results The mean level of 25(OH)D₃ was (56.55±17.62) ng/mL of all 195 HD patients. The total incidence of 25(OH)D₃ inadequacy was only 4.61% (9/195). The incidence of  25(OH)D₃ inadequacy in recent HD patients (18.18%) was significantly higher than that of long-time HD patient (2.89%)(P<0.05). There was no patient with lack of 25(OH)D₃. Multivariable regression analysis showed that there was positive correlation between 25(OH)D₃ and serum calcium level (β=0.203，P=0.010). Conclusion This study indicates that incidence of 25(OH)D3 inadequacy is low in maintained HD patients with stage 5 CKD, which may be caused by long-time and regular calcium and/or VitD supplement.

Key words: chronic kidney disease, maintenance hemodialysis, 25-hydroxyvitamin D3, mineral metabolism, nutrition, dialysis adequacy