Mapping analysis to estimate EQ-5D utility values using the COPD assessment test in Korea

Area of Science:

• Health Economics
• Respiratory Medicine
• Biostatistics

Background:

• No existing mapping algorithms exist between EQ-5D-3L and CAT in Korea.
• COPD Assessment Test (CAT) is widely used, but EQ-5D-3L provides utility values crucial for economic evaluations.
• Bridging this gap is essential for Korean healthcare research.

Purpose of the Study:

• To develop and validate mapping algorithms predicting EQ-5D-3L utility from CAT scores in Korean COPD patients.
• To provide a tool for estimating health state utility values in the absence of direct EQ-5D-3L measurements.

Main Methods:

• Utilized survey data from 300 Korean COPD patients across three tertiary hospitals.
• Developed and validated Ordinary Least Squares (OLS) regression models using training and validation samples.
• Employed bootstrap validation (≥10,000 iterations) to assess model robustness via RMSE and MAE.

Main Results:

• Five CAT items (chest tightness, breathlessness, activity, leaving home, energy) significantly predicted EQ-5D-3L utility.
• Developed OLS mapping algorithms demonstrated effective estimation of overall mean EQ-5D-3L utilities.
• Models tended to overestimate EQ-5D-3L utility for severe COPD patients (utility < 0.6).

Conclusions:

• Developed mapping algorithms can reliably predict EQ-5D-3L utility from CAT scores in Korean COPD patients.
• These algorithms facilitate health economic analyses by enabling utility estimation.
• Application to severe COPD populations requires caution due to potential overestimation of utility values.