Abstract: Objective To analyze serum bone alkaline phosphatase (BAP) level and its associated factors in maintenance hemodialysis (MHD) patients. Methods MHD patients treated in Ruijin Hospital affiliated to Shanghai Jiaotong University School of Medicine in July 1, 2012, more than 18 years old, and more than 3 months of dialysis vintage were enrolled in this study. Clinical, biochemical, and medication data at baseline were collected. Serum BAP levels were determined by an enzyme-linked immunosorbent assay kit. Results This study recruited 226 MHD patients, of whom 144 were males, median age was 58.00 years (48.00～68.00 years), and median dialysis vintage was 41.00 months (21.00～72.25 months). There was no significant difference in serum BAP level between MHD patients and healthy controls [19.71 (14.85～26.72)U/L vs. 21.32 U/L (19.13～28.84 U/L), P>0.05]. In MHD patients, serum BAP level was significantly higher in females than in males [22.41U/L(16.37～32.01 U/L) vs. 18.65U/L(13.81～24.25U/L), Z=-3.199, P＝0.001]. Spearman correlation analyses showed that parathyroid hormone (r=0.569, P＜0.001), alkaline phosphatase (r=0.687, P＜0.001), uric acid (r=0.133, P=0.045), serum phosphorus (r=0.145, P=0.029) were positively correlated with serum BAP level, and body height (r=-0.173, P=0.010), blood bicarbonate level (r=- 0.158, P=0.017), post- dialysis mean arterial pressure (r=- 0.135, P=0.043) were negatively correlated with serum BAP level. Multivariate logistic regression showed that β-blocker treatment (OR 2.600, 95% CI 1.253～5.395, P=0.010), female (OR 2.693, 95% CI 1.336～5.312 , P= 0.004) and PTH (OR 1.005, 95% CI 1.003～1.007 , P＜0.001) were independently correlated with higher BAP in MHD patients (Forward stepwise, P=0.458, Nagelkerke R square 0.339). Conclusion BAP is a sensitive marker for bone metabolism in MHD patients. Females, patients with β- blocker treatment and higher PTH level may have a higher serum BAP level.

Key words: chronic kidney disease, maintenance hemodialysis, chronic kidney disease- mineral and bone disorder, bone alkaline phosphatase, associated factors