COMPARISON OF THE RATING-SCALE AND THE STANDARD GAMBLE IN MEASURING PATIENT PREFERENCES FOR OUTCOMES OF GALLSTONE DISEASE

To estimate patient preferences for gallstone-related treatments and o utcomes, and assess how preferences vary by patient characteristics an d scaling technique, the authors randomly assigned 40 patients without gallstones to interviews based on a rating scale (n = 22) and a stand ard gamble (n = 18). The patients assigned preference Values (possible values 0 to 1) to open cholecystectomy (mean 0.45 by rating scale, 0. 78 by standard gamble), laparoscopic cholecystectomy (0.71, 0.91), ext racorporeal shock-wave lithotripsy (0.77, 0.89), acute cholecystitis ( 0.36, 0.77), lifetime biliary colic (0.41, 0.71), postcholecystectomy syndrome (0.43, 0.79), asymptomatic stone necessitating treatment with bile acids (0.76, 0.96), and surgical scar (0.79, 0.998). Preferences varied little by age, gender, or race. Standard gamble values were hi ghly correlated with, but significantly greater than, rating scale val ues. The authors conclude that patients' preferences for gallstone-rel ated conditions generally are significantly less than one, and differ markedly by the scaling technique used to derive them. These results s hould be considered when patient preferences are incorporated into ana lyses of gallstone treatments.