OSTEOPOROSIS AND BONE MORBIDITY IN CARDIAC TRANSPLANT RECIPIENTS

PURPOSE: To evaluate the incidence and etiology of osteopenia and path ologic fractures in cardiac transplant recipients. PATIENTS: Thirty-on e adult male cardiac transplant recipients and 14 adult men with conge stive heart failure (CHF) awaiting cardiac transplantation. METHODS: A ssessment of indices of bone and mineral metabolism and of bone minera l density (BMD) by dual-energy x-ray absorptiometry. RESULTS: BMD in t he proximal femur was below normal in both groups compared to that in age-matched control subjects, whereas BMD in the lumbar spine was norm al. There was no significant difference in BMD at any site between the two groups. No clinical parameter predicted BMD. In all patients, lab oratory indices of bone mineral metabolism, except parathyroid hormone (PTH) levels, were normal and not statistically different between the two groups. CHF patients had a trend toward elevations of PTH, 1,25-d ihydroxyvitamin D, and urinary calcium excretion compared to transplan t patients. Eight of 31 transplant patients and 2 of 14 CHF patients h ad vertebral compression fractures (c(2) = 11.8, p <0.0006). Transplan t recipients with fractures had twice as many rejection episodes as di d transplant patients without fractures, but did not differ in cumulat ive dose of steroids. Two patients developed avascular necrosis of the femoral head following transplantation. CONCLUSIONS: Cardiac transpla nt recipients and patients with CHF awaiting transplantation had decre ased hip BMD, but normal spine BMD. Although immunosuppressive therapy did not appear to influence bone mass, loop diuretics prior to transp lantation may have stimulated a mild secondary increase in PTH that co uld have differentially caused loss of bone density at the hip in both groups. Pulse corticosteroids used in treating rejection may have con tributed to the increased incidence of vertebral fractures in transpla nt patients. These data suggest that severe CHF with its associated di uretic use and decreased activity are primary contributors to osteopen ia in these patients.