Intravenous Pamidronate is Associated with Reduced Mortality in Patients with Chronic Critical Illness

Abstract

Chronic critical illness (CCI), characterized by prolonged mechanical ventilation and tracheostomy, commonly manifests with elevated bone resorption, which has previously been shown to abate after treatment with intravenous (IV) bisphosphonates. Our study assessed the impact of pamidronate administration on clinical outcomes in a CCI cohort. A retrospective case series was performed on 148 patients admitted to The Mount Sinai Hospital Respiratory Care Unit (RCU) from 2009-2010. We identified patients with CCI who did (n = 30) or did not (n = 118) receive IV pamidronate (30 to 90 mg). Both groups included patients with normal and abnormal renal function. Pamidronate was administered for elevated urine or serum N-telopeptide, hypercalciuria, or hypercalcemia. RCU and 1-year mortality were significantly lower in the pamidronate group (0 and 20%, respectively) compared to nonreceivers (19 and 56%, respectively) (P = .0077 and P = .0004, respectively). After adjusting for differences in baseline creatinine, estimated glomerular filtration rate, and serum calcium, the association with reduced mortality remained significant at 1 year (P = .0132) and with borderline significance for RCU mortality (P = .0911). Creatinine was significantly lower 7 days following pamidronate administration (P = .0025), with no significant difference at 14 days compared to baseline. Pamidronate receivers showed a greater increase in albumin during the RCU stay (2.49 to 3.23 g/dL), compared to nonreceivers (2.43 to 2.64 g/dL) (P = .0007). Pamidronate administration was associated with a significantly reduced rate of hypoglycemia compared to RCU patients not receiving pamidronate (0.09 versus 0.12; P = .0071). Pamidronate use in a CCI population is associated with reduced mortality, lower hypoglycemia rates, improved albumin, and stable renal function. BMI = body mass index CCI = chronic critical illness CI = confidence interval CKD = chronic kidney disease CTx = C-telopeptide eGFR = estimated glomerular filtration rate ICU = intensive care unit IV = intravenous NTx = N-telopeptide PMV = prolonged mechanical ventilation RCU = respiratory care unit.