To explore the relationship between levels of 25-hydroxyvitamin D and parathyroid hormone (PTH) in maintenance hemodialysis (MHD) patients.

A single-center cross-sectional study was conducted, including patients who underwent regular maintenance hemodialysis (MHD) treatment in the Department of Blood Purification of the First Affiliated Hospital of Xi′an Jiaotong University from March 2022 to May 2022. General patient information, as well as laboratory indicators such as serum 25-hydroxyvitamin D, parathyroid hormone (PTH), and alkaline phosphatase, were collected. The patients were categorized into the following groups based on their 25-hydroxyvitamin D levels, PTH levels, and whether they received ordinary vitamin D supplementation: vitamin D normal group, vitamin D insufficient group, and vitamin D deficient group; PTH normal group, PTH mild elevation group, PTH moderate elevation group, and PTH severe elevation group; vitamin D supplement group and vitamin D non-supplement group. The differences in clinical indicators among the groups were compared, and the correlation between 25-hydroxyvitamin D, PTH, and ordinary vitamin D supplement were analyzed with the Spearman′s rank correlation method and multiple linear regression method.

A total of 395 MHD patients were enrolled, with an average age of 51.38±15.10 years, including 260 males and 135 females. The median duration of dialysis was 45.00 (20-75) months. There were 153 patients (38.73%) with vitamin D insufficiency, 59 patients (14.94%) with vitamin D deficiency, and 372 patients (94.18%) with PTH elevation. The levels of alkaline phosphatase and PTH, as well as the proportions of females, aortic calcification, and abdominal aorta calcification, were significantly higher in the vitamin D deficiency group than in the vitamin D normal group (all P<0.05). The dialysis duration, serum creatinine, serum phosphorus, alkaline phosphatase, albumin, and the proportions of aortic calcification and abdominal aortic calcification were significantly higher, while the 25-hydroxyvitamin D level was significantly lower, in the PTH severe elevation group than in the normal PTH group (all P<0.05). The correlation analysis revealed a negative correlation between PTH and 25-hydroxyvitamin D (r=-0.191, P<0.01). In addition, there was no correlation between supplementation of ordinary vitamin D and PTH (β=-42.725, P=0.280).

The MHD patients generally suffered from vitamin D insufficiency or deficiency, accompanied with PTH elevation. Their 25-hydroxyvitamin D was negatively correlated with PTH, while no significant correlation was found between ordinary vitamin D supplement and PTH.