A comparison of physician-rated disease severity and patient reported outcomes in mild to moderately active ulcerative colitis

摘要

Background and aims: The aim was to derive health state utility scores in ulcerative colitis (UC) byestablishing the relationship between the physician-rated ulcerative colitis disease activity index(UCDAI) and a patient reported EQ-5D by statistically mapping the two instruments.Methods: In a randomised controlled trial comparing oral plus enema mesalazine treatment with oralmesalazine treatment alone (PINCE), UCDAI and EQ.-5D scores were collected in parallel from patientswith active UC. From these data, multinomial logistic regression was used to estimate responseprobabilities to each of the five domains of the EQ-5D index from assessment of UC disease severityusing original and abbreviated (no endoscopy) versions of the UCDAI. Predicted EQ.-5D responses wereconverted by Monte Carlo simulation to the EQ-5D index for predicting health-related quality of life(HRQpL). The reliability of the algorithm was tested using UCDAI scores from a second mesalazine RCT(PODIUM).Results: The abbreviated-UCDAI showed comparable explanatory performance to the full UCDAI. Forpatients in remission, mean utility was 0.939,0.944, and 0.940 U for PINCE_(estimated). PINCE_(observed), andPODIUM, respectively. Mild/moderate and relapsing cases showed mean utilities of 0.801, 0.811, and0.775, respectively; whilst for those in severe relapse, the mean utilities were 0.630, 0.700 and0.660 units, respectively. The mean squared error between actual and predicted utilities fromobservations in PINCE was 0.019.Conclusion: Response mapping of UC activity to EQ.-5D domains produced reliable estimates ofpatient-rated health state utility consistent with UCDAI rated severity. Comparing abbreviated-UCDAI and full UCDAI suggests that inclusion of endoscopy scores has limited predictive value in estimating patient HRQpL.