Institution of a Bone Health Protocol Using an Intravenous Bisphosphonate During Index Heart Transplant Hospitalization

Abstract

<h3>Purpose</h3> Steroid exposure is a leading risk factor for osteoporotic bone fractures, and more than 10% of heart transplant patients develop fractures. Bisphosphonates are effective at preventing fractures in the post-transplant population. We assessed the implementation of a prophylactic bone density preservation protocol after heart transplantation. <h3>Methods</h3> This single-center retrospective analysis included 21 consecutive heart transplant recipients (HTRs) from March to September 2021. HTRs were protocolized to receive a loading dose of ergocalciferol (at least four doses of 50,000 units daily) followed by intravenous bisphosphonate (5 mg zoledronic acid [ZA]). Patients were prescribed calcium citrate and vitamin D on discharge. <h3>Results</h3> The 21 consecutive HTRs included 16 men and 5 women (average age 58.1±10.9 years). Of HTRs with a 25-OH-vitamin D level measured in the 90 days prior to ZA administration (57.1%; 12/21), the average level was 24.0±11.6 ng/mL. High-dose ergocalciferol was given to 95.2% (20/21) during index hospitalization. ZA was administered to 95.2% (20/21) during index hospitalization at a median of 11 days post-transplant. ZA was delayed due to impaired renal function until 130 days post-transplant in one patient. Among those receiving ZA during the index admission, the average glomerular filtration rate on the day of ZA administration was 66.6±27.1 mL/min/1.73m2. No fevers or infusion reactions occurred in the 72 hours following ZA administration in any patients. There was no difference in the white blood cell (WBC) count between the day prior to ZA administration (day -1; 8,816±2,930 cells/uL) and the day of ZA administration (day 0; 8,842±2,412 cells/uL), yet the WBC count increased to 10,819±3,651 cells/uL on day +1 and further to 12,771±4,668 cells/uL on day +2 (p = 0.002 and 0.0006 for comparisons to day 0, respectively). Serum calcium levels declined from 8.7±0.4 mg/dL on day 0 to 8.3±0.5 mg/dL on day +4 (p = 0.003). Most patients were discharged with calcium (95.2%; 20/21) and vitamin D (81.0%; 17/21) supplementation. No fractures have been reported. <h3>Conclusion</h3> A bone density protection protocol utilizing index-admission intravenous bisphosphonate therapy coupled with calcium and vitamin D was implemented with reassuring tolerability. Similar approaches may ensure effective bone health pharmacotherapy.