Vertebral morphometry by X-ray absorptiometry before and after liver transplant: a cross-sectional study

To evaluate bone density and fracture prevalence in patients with end-stage liver diseases (ESLD) awaiting liver transplant and in orthotopic liver-transplant (OLTx) recipients by using dual energy X-ray absorptiometry.

In a cross-sectional study 27 patients (16 males and 11 females, mean age 49.9 +/- 1.7 years) with ESLD, and 36 subjects (26 males and 10 females, mean age 50.5 +/- 1.6 years) who had undergone OLTx 1-70 months before, were recruited.

All patients underwent biochemical assessment of mineral metabolism. Bone density measurement of the spine and femur and morphometric X-ray absorptiometry (MXA) of the vertebrae were also obtained.

Bone density was decreased in both groups as compared to the expected normal values. Spinal density did not differ between the two groups, while femoral bone mass was lower in OLTx than in ESLD patients (T-scores of: femoral neck -1.91 +/- 0.16 vs -1.12 +/- 0.22, P < 0.01; total femur -1.62 +/- 0.16 vs -0.94 +/- 0.23, P < 0.02). Bone alkaline phosphatase was the only independent predictor of femoral density (R2 = -0.21, P < 0.05). Symptomatic fractures were reported by 25% of OLTx and 15% of ESLD patients. MXA vertebral fractures were present in 28% of OLTx and 7.5% of ESLD (P < 0.05) patients. Most of these fractures had been asymptomatic. Total methylprednisolone intake was higher in patients with MXA vertebral fractures than in non-fractured patients (P < 0.05).

Fragility fractures, especially of the spine, occur more frequently after liver transplantation, with corticosteroid treatment being the most important risk factor. Morphometric X-ray absorptiometry represents a useful technique for identifying vertebral fractures even in liver transplanted patients.