An Evaluation of Utility Measurement in Crohnʼs Disease

Abstract

We evaluated the use of utility measurements to assess the quality of life of patients with Crohn's disease. Utility scores were obtained using the Time Trade-Off (TTO), Standard Gamble, and Visual Analog Scale (VAS) methods in 180 consecutive patients with Crohn's disease. The mean utility scores of patients with a spectrum of disease severity were compared with other measures of disease activity to assess the operating properties of these instruments. All methods of utility estimation yielded lower mean scores in patients with more severe disease. (Remission versus chronically active, therapy resistant disease: TTO 0.96 versus 0.88; Standard Gamble 0.88 versus 0.74; VAS 0.84 versus 0.61). TTO scores were consistently higher than those derived by the other methods (p = 0.001). The utility scores were reliable in patients who were stable (intraclass correlation coefficient 0.55-0.84), but were less responsive than the Crohn's Disease Activity Index (responsiveness ratio 0.97-1.3 versus 2.10) to changes in disease severity. Patients with active Crohn's disease have decreased quality of life as measured by utility scores. Although utilities are valid and reliable quality of life assessments, they are less responsive than other measures of outcome used for clinical trials.