Abstract: 【Abstract】Objective There are only a few data at Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, about the prevalence and management of bone and mineral metabolism disorders in patients on maintenance hemodialysis (MHD). In this study, we retrospectively analyzed serum calcium, phosphorus and intact parathyroid hormone (iPTH) in the MHD patients treated in Hemodialysis Center of Ren Ji Hospital, and evaluated their calcium and phosphorus metabolism disturbances. Methods MHD patients treated in Ren Ji Hospital between Jan. 1, 2007 and Dec. 31, 2013 were enrolled in this study. They were followed up to the end-point of death, cessation of hemodialysis, transfer to other blood purification centers, or to the end of follow-up period (Dec. 31, 2013). Laboratory parameters including serum albumin, hemoglobin, phosphorus, calcium, iPTH, and high sensitivity C reactive protein (hs-CRP) were measured every 3 months. Result A total of 528 MHD patients (mean age 55.3±17.6 years, 60.8% males) were recruited in this study. Serum calcium, phosphorus and iPTH met the target levels suggested by the Kidney Disease Outcomes Quality Initiative (K/DOQI) accounted for 51.3%, 39.0% and 26.1%, respectively, of the patients. Serum calcium was higher in females (2.34±0.23 mmol/L) than males (2.28±0.20 mmol/L, P=0.024). Compared with younger
patients (age ＜65), older patients (age >65) had relatively lower phosphorus (1.75±0.40 vs. 2.02±0.40 mmol/ L, P＜0.001) and iPTH (223.76 pg/ml vs. 352.36 pg/ml, P＜0.001). iPTH >600 pg/ml was found in 18% patients, and iPTH ＜150 pg/ml in 25.6% patients. Patients with hemodialysis thrice a week had lower serum phosphorus and higher serum calcium than those with hemodialysis twice a week (1.87 ± 0.42 mmol/L vs. 1.95±0.41 mmol/L, P=0.043 for phosphorus; 2.32±0.21 mmol/L vs. 2.27±0.22 mmol/L, P=0.022 for calcium). Patients on MHD for more than 5 years had significantly higher serum calcium, phosphorus, and iPTH than those on MHD for less than 5 years (2.35±0.22 mmol/L vs. 2.23±0.18 mmol/L, P＜0.0001 for calcium; 1.95± 0.41mmol/L vs. 1.84 ± 0.44 mmol/L, P= 0.027 for phosphorus; 443.17±393.76 pg/ml vs. 285.19±282.95 pg/ml, P＜0.0001 for iPTH). Multiple and stepwise linear regression indicated that serum albumin (P=0.001), calcium (P＜0.001), iPTH (P＜0.001), age (P＜0.001) and dialysis vintage (P=0.004) were the independent risk factors for hyperphosphatemia. Conclusions Hyperphosphatemia and hyperparathyroidism were relatively common in MHD patients, especially in those with hemodialysis twice a week and those with hemodialysis vintage for more than 5 years. Serum albumin, calcium, iPTH, age and dialysis vintage were the independent risk factors for hyperphosphatemia.

Key words: Maintenance hemodialysis, Mineral and bone disorder, Dialysis vintage