Hyperphosphatemia and Sudden Death in Hemodialysis Patients: A Silent Threat in Kidney Disease.

Introduction: Sudden death (SD) is a leading cause of mortality among hemodialysis patients. While hyperphosphatemia is a significant risk factor for cardiovascular and overall mortality, There is insufficient research examining the link between serum phosphate levels and the risk of sudden death. Aim: This study seeks to enhance the understanding of the relationship between serum phosphate levels and the risk of sudden death in patients receiving hemodialysis. Method: A prospective study was conducted at the renal division of the Sindh Institute of Urology and Transplantation (SIUT) in Karachi, Pakistan, involving patients with end-stage kidney disease (ESKD) of any etiology undergoing maintenance hemodialysis via permanent access. Participants who experienced cardiac symptoms and unexpectedly died of natural causes within 1 to 24 hours after the onset of symptoms during hemodialysis, without any prior fatal condition, were included. These patients were categorized into two groups based on their serum phosphate levels measured closest to their sudden death. Results: The study enrolled 175 patients who experienced cardiac symptoms, with a mean age of 44.23±14.87 years and a slight male predominance (53.1% male vs. 46.9% female). Both groups had an equal prevalence of hypertension, while more patients in Group 1 had diabetes (25.5% vs. 22.07%) and cardiovascular disease (25.5% vs. 25.97%). The mean duration of hemodialysis was similar between the groups. A significant relationship between phosphate levels and sudden death was observed (P=0.02), and Kaplan–Meier curves indicated that patients with higher baseline serum phosphate levels had a greater probability of experiencing sudden death (log-rank p=0.037). Elevated alkaline phosphatase (ALP) levels alongside hyperphosphatemia were significantly associated with an increased risk of total mortality (P=0.002). Conclusion: Hyperphosphatemia is independently linked to a higher risk of sudden death in patients undergoing hemodialysis.