Increased active PTH(1–84) fraction as a predictor of poor mortality in male hemodialysis patients
We reported previously that serum parathyroid hormone [PTH(1–84)]/intact PTH[PTH(1–84) + PTH(7–84)] ratio provides the better marker for parathyroid function and bone turnover state than serum PTH level itself. The present study demonstrated that higher PTH(1–84)/intact PTH ratio, but not serum PTH(1–84) and intact PTH, predicted higher all-cause mortality in 177 male hemodialysis patients. We reported that PTH(1–84)/intact PTH ratio provides a clinically relevant marker for parathyroid function and the resultant bone turnover state. The purpose of our study was to investigate the association of PTH(1–84)/intact PTH ratio with all-cause mortality (ACM) in male hemodialysis patients. The study was performed for 70 months. Serum PTH in 177 male hemodialysis patients was measured with PTH(1–84)-specific whole PTH assay and intact PTH assay which cross-reacts with N-truncated PTH including PTH(7–84). The patients (n = 177) were divided into higher and lower halves based on serum levels of PTH(1–84)/intact PTH ratio (cutoff value, 0.484), intact PTH (143.8 pg/mL), and PTH(1–84) (64.1 pg/mL). In Kaplan–Meier analysis, the higher group in whole PTH/intact PTH ratio had significantly higher ACM than the lower group (P = 0.020 by log-rank test), in contrast with the insignificant difference between the higher and lower groups in intact PTH and PTH(1–84). Multivariate Cox regression hazard analysis identified higher log [PTH(1–84)/intact PTH ratio], but not log intact PTH or log PTH(1–84) as a significant independent predictor [hazard ratio 14.428 (95 % CI 2.486–83.728)] for ACM after adjustment for various factors including age, hemodialysis duration, presence/absence of diabetes mellitus, BMI, log C-reactive protein, serum albumin, calcium, and phosphate. The association existed between log [PTH(1–84)/intact PTH ratio] and ACM in those without vitamin D administration (n = 95). Higher PTH(1–84)/intact PTH ratio, which provides a relevant marker for parathyroid function, may be a significant predictor of ACM in male hemodialysis patients.