Elevated parathyroid hormone predicts mortality in dialysis patients undergoing valve surgery

Abstract

Dialysis patients requiring valve surgery have high morbidity and mortality rates. Although elevated serum parathyroid hormone (PTH) levels are associated with increased mortality in dialysis patients, this correlation has not been investigated in patients undergoing cardiac valve operations. This study assesses the impact of PTH levels on mortality in dialysis patients undergoing valve operations. A retrospective analysis of 109 dialysis patients undergoing valve operation with preoperative PTH levels between 1996 and 2007 at a US academic center was performed. Cox regression analyses were done using PTH as a binary variable. The patients were followed from the date of the operative procedure until death or loss to follow-up. Higher mortality risk was seen once preoperative PTH exceeded 200 pg/mL (hazard ratio [HR], 3.43; P = .003). Mean survival was improved in the PTH < 200 pg/mL group when compared with the PTH ≥ 200 pg/mL group (86.7 vs 40.3 months, respectively). Other independent predictors of mortality included serum phosphate (HR, 1.20; P = .017), calcium-phosphate product (HR, 1.02; P = .038), and history of myocardial infarction (HR, 2.12; P = .015). Preoperative PTH level ≥ 200 pg/mL is predictive of increased mortality after valve surgery among dialysis patients. Hyperparathyroidism should be investigated further as a possible modifiable risk factor for postoperative mortality in this high-risk patient cohort.