Bone metabolism in orthotopic liver transplantation: a prospective study

Abstract

Bone mineral density (BMD) and mineral metabolism were assessed in 54 patients with end-stage liver disease who were evaluated for orthotopic liver transplantation (OLT) and assessed 3, 6, and 12 months after surgery in 26 patients who underwent OLT. Serum and urinary electrolyte and mineral levels, serum liver function test results, and parathyroid hormone (PTH), osteocalcin (BGP), 25-hydroxyvitamin D, and urinary hydroxyproline levels were assessed. BMD of the lumbar spine was measured at baseline and 3, 6, and 12 months after OLT. At baseline, 40.7% of patients had BMD below the fracture threshold (0.800 g/cm2). Using multiple stepwise regression analysis, we found that BMD was significantly (P < .0001) affected by age, serum creatinine level, and PTH level but not by indices of cholestasis or liver function. In the patients who underwent OLT, a 1.4% reduction (P < .006) was observed in BMD 3 months after OLT. Thereafter, BMD returned to pretransplant values. A significant increase in serum BGP was observed after 6 (P < .02) and 12 (P < . 005) months. PTH levels increased progressively 3 (P < .02), 6 (P < . 001), and 12 (P < .0001) months after OLT. This increase did not seem to be caused by cyclosporine-induced nephropathy. It was concluded that osteopenia is a major complication in hepatic cirrhosis, regardless of its causes. The increase in serum BGP levels 6 and 12 months after OLT indicates metabolic activation of osteoblasts. The increase in PTH levels after OLT warrants further investigation.