Association between serum intact parathyroid hormone and survival in dialysis patients

Purpose: To examine the relationship between serum intact parathyroid hormone (iPTH) levels and survival in maintenance dialysis patients.

Methods: We retrospectively reviewed the data of patients who began and continued dialysis from January 2013 to December 2022. Patients were categorized based on their baseline and time-averaged (TA) iPTH levels into three groups: low (iPTH < 150 pg/ml), medium (150 ≤ iPTH < 300 pg/ml), and high (iPTH ≥ 300 pg/ml). We utilized the Kaplan-Meier method to assess survival differences, the Cox proportional hazards regression model to identify risk factors impacting adverse outcomes and the restricted cubic spline model to evaluate the association between iPTH levels and the all-cause mortality.

Results: We included a total of 1023 participants, comprising 524 hemodialysis and 499 peritoneal dialysis. Kaplan-Meier analysis showed that high baseline group had higher survival and low baseline group had poorer survival, compared with medium baseline group, respectively (χ² = 44.974, P < 0.001). The three TA groups showed similar results (χ² = 67.316, P < 0.001). Multivariate COX regression analysis showed that low TA iPTH was an independent risk factor for all-cause death (hazard ratio [HR] = 1.655, 95% CI 1.159-2.365, P = 0.006). The restricted cubic spline model revealed an L-shaped connection between TA iPTH level and the all-cause mortality with an inflection point of 193 pg/ml.

Conclusion: The survival for maintenance dialysis patients varies significantly based on their baseline and time-averaged iPTH levels, with time-averaged iPTH emerges as an independent risk factor for all-cause death in these patients.