Scores on the COPD Assessment Test (CAT) are associated with 3-year mortality rates in patients with idiopathic pulmonary fibrosis (IPF) and other forms of fibrotic interstitial lung disease (FILD), according to a new study published in Respiratory Investigation.
The study results showed that patients with high (21-30 points) and very high (31-40 points) CAT impact scores were at a 2-fold (hazard ratio [HR], 1.990; 95% CI,1.109-3.573) and 3-fold (HR, 2.930; 95% CI, 1.400-6.126) increased risk of mortality. This was compared to low impact scores (<10).
“The present study showed that CAT score has prognostic value in patients with FILD, and that its severity category provides prognostic information in clinical practice,” the authors said.
The association was maintained even after adjustments were made to Cox proportional hazard models (P =.001). The adjustments were patient age, sex, forced vital capacity, diffusion capacity of carbon monoxide, IPF diagnosis, and usual interstitial pneumonia pattern on high-resolution computed tomography.
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The relationship between CAT score and 3-year mortality was also present in subgroup analysis of patients with only IPF.
In the study, the CAT scores were also found to be associated with a number of clinical variables, including pulmonary function, dyspnea, exercise capacity, and the Hospital Anxiety and Depression Scale (HADS) score using Spearman’s correlation analysis.
“The strength of the CAT was that it could capture symptoms that may impair health status other than breathlessness and cough,” the authors added.
A total of 501 patients with FILD were included in the study analysis. The disease makeup included 188 patients with IPF, 16 with nonspecific interstitial pneumonia, 14 with chronic hypersensitivity pneumonia, 166 with unclassified interstitial lung disease (ILD), and 117 with connective tissue disease-associated ILD. The median age of patients was 68 years and 320 patients (63.9%) were male.
Baseline CAT scores for patients fell into 4 impact levels, with 40.5% having low impact, 38.7% medium impact, 15.8% high impact, and 5.0% with very high impact.
Over the 3-year study period, 118 patients died, of which 71 had IPF.
All patients in the study underwent the CAT, the Modified Medical Research Council dyspnea scale, the HADS, the pulmonary function test, and the 6-Minute Walk Test.
Matsuda T, Kondoh Y, Furukawa T, et al. The prognostic value of the COPD Assessment Test in fibrotic interstitial lung disease. Respir Investig. Published online September 20, 2021. doi:10.1016/j.resinv.2021.07.007