Abstract
The chronic obstructive pulmonary disease (COPD) Assessment Test (CAT), which was developed to measure the health status of patients with COPD, was applied to patients with interstitial lung disease, aiming to examine the CAT as a predictor of outcome. Over a follow-up period of more than one year, 101 consecutive patients with interstitial lung disease were evaluated by the CAT. The CAT scores of 40 in total were categorized into four subsets according to the severity. Patients with higher (more severe) scores exhibited lower forced vital capacity and lung diffusion capacity for carbon monoxide. The survival rate was significantly lower in patients with higher scores (log-rank test, P = 0.0002), and the hazard ratios for death of the higher scores and lower lung diffusion capacity for carbon monoxide were independently significant. These findings suggest that CAT can indicate the risk of mortality in patients with interstitial lung disease.