TITLE:
Application of the COPD Assessment Test (CAT) to Patients with Interstitial Lung Disease
AUTHORS:
Fujiko Someya, Takao Nakagawa
KEYWORDS:
Interstitial Lung Disease, Quality of Life, Questionnaire, Pulmonary Function, Oxygen Saturation, Home Oxygen Therapy
JOURNAL NAME:
Health,
Vol.6 No.19,
November
7,
2014
ABSTRACT: The COPD Assessment
Test was recently developed to assess health status in patients with COPD. However,
little was known about its application to patients with interstitial lung
disease, so we examined the relationship between the COPD Assessment Test score
and respiratory impairment including the clinical picture in subjects with
interstitial lung disease. Data were collected retrospectively from 52 consecutive
subjects with interstitial lung disease on admission to our facility. All
subjects completed the COPD Assessment Test, in which a higher score represented
a worse health status. They were also assessed by pulmonary function test, SpO2 during 6-min walk test, and arterial blood gases. The COPD Assessment Test
score was negatively correlated with the percentage of predicted forced vital
capacity, forced expiratory volume in 1 second, total lung capacity, diffusion
capacity of the lung for carbon monoxide, and PaO2 (p = 0.0005, 0.005, 0.0002, 0.0005, and 0.002,
respectively). Breathlessness was detected as the high scoring item, while
phlegm and sleep were the last affected items. The COPD Assessment Test score
was higher in subjects with oxygen desaturation in SpO2 (≥4%) during
6-min walk test (p = 0.0001) and in
subjects on home oxygen therapy (p = 0.0007).
More than 75% of subjects with oxygen desaturation during walking were
classified into a medium or severer impact level of the COPD Assessment Test
score, and subjects on home oxygen therapy were classified into a high or
severer impact level. PaCO2 in room air and SpO2 at rest
did not correlate with the COPD Assessment Test score. The reliability of items
in the COPD Assessment Test was 0.87 by Cronbach’s α coefficient. Our results suggest that the COPD Assessment Test
may be a candidate for evaluating the health status and impact of disease on
patients with interstitial lung disease.