PMID- 27325339 OWN - NLM STAT- MEDLINE DCOM- 20170517 LR - 20191210 IS - 1524-4733 (Electronic) IS - 1098-3015 (Linking) VI - 19 IP - 4 DP - 2016 Jun TI - Mapping the COPD Assessment Test onto EQ-5D. PG - 469-77 LID - S1098-3015(16)00011-5 [pii] LID - 10.1016/j.jval.2016.01.005 [doi] AB - OBJECTIVES: To develop an algorithm for estimating EuroQol five-dimensional questionnaire (EQ-5D)-equivalent utilities from the chronic obstructive pulmonary disease (COPD) assessment test (CAT) and evaluate its use in economic evaluations as part of health technology assessments for COPD. METHODS: Data for the three-level EQ-5D (EQ-5D-3L) and the CAT were obtained from two multinational, phase III clinical trials. Three approaches were explored for estimating EQ-5D-equivalent utilities from the CAT: ordinary least-squares (OLS) regression, multinomial logistic regression, and a combination of the two. Estimated utilities were compared with actual EQ-5D-3L utilities, including treatment effect and the impact of disease severity on health, to evaluate the predictive performance of each algorithm. RESULTS: Root mean squared error and mean absolute error analyses showed that an OLS algorithm performed as well as algorithms developed using more complex modeling structures. The OLS regression included EQ-5D-3L utility weights as dependent variables and CAT items as independent variables. Within-sample validation showed systematic overestimation and underestimation within the range 0.5