Inadequate dietary intake but not renal tubular acidosis is associated with bone demineralization in primary biliary cirrhosis.

BACKGROUND: Metabolic bone disease associated with primary biliary cirrhosis (PBC) is inadequately characterized. Renal tubular acidosis (RTA) may lead to bone loss through chronic mobilization of skeletal calcium salts to buffer increased acid load. AIM: To evaluate the prevalence of RTA in PBC and establish the relationships among bone mineral density (BMD), renal function and nutritional status. METHODS: We enrolled 69 female patients with compensated PBC and 35 control patients with chronic hepatitis C. RTA was searched in all patients, and 24-h dietary recalls were collected at enrolment. BMD was measured by dual-energy X-ray absorptiometry at the femur neck, lumbar spine and radius ultradistalis sites. RESULTS: No patients received a diagnosis of RTA. BMD values (Z-scores) showed only little deviation from normal population with no difference between PBC and controls. Osteopoenic PBC patients (T-score < 1) showed significantly lower daily phosphorus intake [median: 672 (288-1374) vs. 921 (253-1923) mg/day; P = 0.037], with a trend towards lower caloric intake than their nonosteopoenic counterparts. CONCLUSIONS: Renal tubular acidosis is uncommon in compensated PBC. Cholestasis is not associated with an increased risk of bone demineralization. Inadequate dietary intake may be a preventable factor contributing to bone loss in PBC.

Parenteral calcitonin for metabolic bone disease associated with primary biliary cirrhosis.

No satisfactory treatment is available for metabolic bone disease associated with primary biliary cirrhosis. On the basis of the similarities to postmenopausal osteoporosis, the rationale exists for calcitonin to be tested in clinical studies in patients with primary biliary cirrhosis-associated osteoporosis. We evaluated the effect of calcitonin on bone metabolism and mineral density in 25 women with primary biliary cirrhosis and severe osteopenia. After 6 mo of observation, patients received a synthetic calcitonin or a control treatment consisting of less than one hundredth of the recommended dose of porcine calcitonin. The two treatments were administered in sequence to each patient for two 6-mo periods, with a 3-mo washout between them, according to a crossover design. After the observation period, oral calcium supplementation was started. Bone mineral density was measured by dual-photon absorptiometry of the lumbar spine at study entry and at the beginning and the end of each treatment period. During the observation period bone mineral density fell by 3.5% whereas during the following 6 mo it increased in both the patients who received calcitonin (4.3%) and those who received the control treatment (4.9%). Conversely, after the crossover, bone mineral density decreased during both calcitonin (-2.7%) and control treatment (-2.9%). A significant difference was observed between the two periods but not between the two treatments or between the two sequences of treatment administration. In conclusion, our findings indicate that parenterally administered calcitonin for 6 mo is ineffective in halting bone loss in patients with primary biliary cirrhosis-associated metabolic bone disease, whereas calcium supplementation may have a transient beneficial effect.

Effects of ursodeoxycholic acid therapy for liver disease associated with cystic fibrosis.

The hydrophilic bile acid ursodeoxycholic acid (UDCA) has recently been shown to improve indexes of liver function in adult patients with various liver diseases. The clinical and biochemical responses to UDCA administration (10 to 15 mg/kg body weight per day) were therefore investigated in nine patients with cystic fibrosis and evidence of liver disease. All patients were receiving pancreatic enzymes and taurine supplementation. Liver function tests were done and serum bile acid concentrations and biliary bile acid composition were determined before and during UDCA therapy; fat balance studies and fecal bile acid excretion were carried out before and 6 months after UDCA treatment. After 2 months of bile acid therapy, biliary bile acid composition was enriched in UDCA from approximately 5% before treatment to 25%, at the expense of cholic and chenodeoxycholic acids, thus making the pool more hydrophilic. This enrichment is lower than that reported for adults with chronic liver diseases. Serum concentrations of UDCA increased significantly but variably. UDCA became the predominant fecal bile acid excreted (12% to 67%), indicating a variable absorption of the administered bile acid. Liver function improved in all patients after 2 to 6 months of therapy, although the degree of improvement (aspartate aminotransferase, -34%; alanine aminotransferase, -41%; gamma-glutamyltranspeptidase, -41% alkaline phosphatase, -19%) was lower than that observed in adults with chronic liver diseases. Mean coefficient of fat absorption and growth rate were, on average, unaffected by UDCA therapy, although an improvement was noted for three patients with greater severity of steatorrhea. The study indicates that UDCA can be used safely in this patient population but that higher doses of UDCA may be of greater benefit in the treatment of the liver disease associated with cystic fibrosis.