Low serum intact parathyroid hormone level is an independent risk factor for overall mortality and major adverse cardiac and cerebrovascular events in incident dialysis patients

Summary: Abnormal bone dynamics is a major risk factor for cardiovascular disease in patients with chronic kidney disease. The level of serum intact parathyroid hormone (iPTH) is widely used as a bone dynamic marker. We investigated the effect of the mean level of serum iPTH on overall mortality and cardiovascular outcomes in incident dialysis patients. Purpose: Chronic kidney disease–mineral bone disorder (CKD–MBD) is a major risk factor for cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD). CKD–MBD is classified as low- or high-turnover bone disease according to the bone dynamics; both are related to vascular calcification in ESRD. To evaluate the prognostic value of abnormal serum parathyroid hormone (PTH) levels on ESRD patients, we investigated the effects of time-averaged serum intact PTH (TA-iPTH) levels on overall mortality and major adverse cardiac and cerebrovascular events (MACCEs) in incident dialysis patients. Methods: Four hundred thirteen patients who started dialysis between January 2009 and September 2013 at Yonsei University Health System were enrolled. The patients were divided into three groups according to TA-iPTH levels during the 12 months after the initiation of dialysis: group 1, <65 pg/ml; group 2, 65–300 pg/ml; and group 3, >300 pg/ml. Cox regression analyses were performed to determine the prognostic value of TA-iPTH for overall mortality and MACCEs. Results: The mean age of the patients was 57 ± 15 years, and 222 patients (54 %) were men. During the median follow-up of 40.8 ± 29.3 months, 49 patients (12 %) died, and MACCEs occurred in 55 patients (13 %). The multivariate Cox regression analyses demonstrated that a low TA-iPTH level was an independent risk factor for both overall mortality (group 2 as reference; group 1: hazard ratio (HR) = 2.06, 95 % confidence interval (CI) = 1.11–3.83, P = 0.023) and MACCEs (HR = 1.82, 95 % CI = 1.04–3.20, P = 0.036) in incident dialysis patients after adjustment for confounding factors. Conclusion: Low serum TA-iPTH is a useful clinical marker of both overall mortality and MACCEs in patients undergoing incident dialysis, mediated by vascular calcification.