Background: Osteoporosis and related fractures are a major complication after organ transplantation. The aim of this study was to find out the frequency and predictors of osteoporotic fractures after cardiac or liver transplantation.
Methods: 235 consecutive patients who had a cardiac transplant (n=105; 88 men, 17 women) or a liver transplant (130; 75 men, 55 women) were followed. Vertebral fractures were assessed by a standardised analysis of spinal radiographs before and annually after transplantation. Clinical and non-vertebral fracture data were noted from hospital records.
Findings: In the first and second years after transplantation, the proportion of patients (Kaplan-Meier estimates) who had at least one vertebral fracture was slightly higher in the cardiac group (first year 21%, second year 27%) than in the liver group (first year 14%, second year 21%). In the third and fourth years, one third of patients from both groups had had one or more vertebral fractures. Non-vertebral fractures occurred in nine patients (7%) after liver transplantation and avascular necrosis of the hip head in three patients (3%) after cardiac transplantation. In both groups, no dose-dependent effect of immunosuppressive therapy on fracture development could be identified. Independent predictors assessed by multivariate analysis were age (hazard ratio [95% CI] increase of 5 years, 1.71 [1.1-2.7]) and lumbar bone-mineral density (decrease of 1 SD t score, 1.97 [1.2-3.2]) in cardiac transplantation patients, and vertebral fractures before transplantation (6.07 [1.7-21.7]) in the liver group.
Interpretation: The high frequency of osteoporotic fractures in the 2 years after transplantation and the limitations of reliable fracture-risk predictions, show the need to investigate preventive therapies.