Objectives: The appearance of gallstone opacification during oral bile acid administration indicates that stones are no longer susceptible to dissolution and represents, therefore, a definitive treatment failure. Ursodeoxycholic acid (UDCA) has been imputed to facilitate gallstone opacification; however, data regarding the comparative occurrence of gallstone opacification during UDCA and chenodeoxycholic acid (CDCA) administration are not yet available. Our objectives were to evaluate the frequency of acquired opacification in gallstone patients taking UDCA and in gallstone patients taking CDCA, to verify whether or not gallstone opacification is a peculiar side effect of UDCA treatment and, further, to evaluate gallstone opacification in gallstone patients receiving tauro-UDCA (TUDCA) to verify whether the administration of the more soluble tauroconjugate might prevent the deposition of calcium salts on the stone surface.
Methods: 106 gallstone patients on UDCA, 125 gallstone patients on CDCA, and 31 gallstone patients on TUDCA were evaluated. Before treatment, all patients had radiolucent gallstones as assessed by oral cholecystography; further cholecystographic evaluations were performed every 6 months during treatment.
Results: The frequency of gallstone opacification was 13.2% (14/106) in UDCA patients, 8.8% (11/125) in the CDCA patients, and 12.9% (4/31) in the TUDCA patients. The differences were not statistically significant (p = NS). Sex, stone size, dose of bile acid, and duration of treatment were not significantly related to an increased frequency of gallstone calcification in any of the treatment groups. The frequency of gallstone opacification appeared to be higher in older patients.
Conclusions: 1) UDCA rich bile is not a major predisposing factor for acquired gallstone opacification; 2) the administration of TUDCA does not prevent gallstone opacification; 3) opacification could be related to the natural history of gallstone disease.