Abstract: Objective To investigate the blood magnesium levels of the elderly patients undergoing maintenance hemodialysis (MHD), and to analyze the levels of blood pressure, intact parathyroid hormone (iPTH) and nutritional status in the patients with different levels of blood magnesium. Methods A total of 99 elderly MHD patients were enrolled and divided into low-magnesium group (＜0.75 mmol/L, n=24), normal-magnesium group(0.75-1.02 mmol/L, n=45) and high-magnesium group (＞1.02 mmol/L, n=30) according to the level of blood magnesium before hemodialysis. The levels of calcium, phosphorus, iPTH, plasma albumin, hemoglobin before hemodialysis and the blood pressure during hemodialysis and hemodialysis interval were observed and compared among the three groups. Results There was no significant difference in interdialytic blood pressure among the groups with different magnesium levels. The systolic blood pressure in the low-magnesium group was significantly lower than that in the normal-magnesium group and high-magnesium group (P<0.01), and the diastolic blood pressure in the low-magnesium group was significantly lower than that in the normal-magnesium group (P<0.01). The levels of iPTH, calcium, phosphorus and hemoglobin were significantly increased in the low-magnesium group, followed by the normal-magnesium group and the high-magnesium group (P<0.01). The plasma albumin level in the normal-magnesium group was significantly higher than that in the low-magnesium group (P<0.05). Conclusions Elderly MHD patients with normal or elevated blood magnesium levels usually have relatively normal nutritional status, relatively stable blood pressure and high level of iPTH during dialysis.

Key words: maintenance hemodialysis, serum magnesium, intact parathyroid hormone, blood pressure, nutritional status