Relationship between chronic obstructive pulmonary disease (COPD) assessment test score and prognostic factors of COPD patients

Abstract

Objective To observe the correlation between chronic obstructive pulmonary disease(COPD)assessment test (CAT)score and prognostic factors,so as to investigate the value of CAT score in predicting the prognosis of COPD. Methods A total of 81patients with newly diagnosed COPD in our hospital during Jul.2011to Sep.2012,without using inhaled corticosteroid(ICS)/long-actingβ2agonist(LABA)or long-acting antimuscarinic agent(LAMA),were divided into group A (low risk,less symptoms),B (low risk,more symptoms),C (high risk,less symptoms)and D (high risk,more symptoms)groups according to Global Initiative for Chronic Obstructive Lung Disease(GOLD,2011edition),and the patients were given ICS/LABA or ICS/LABA+LAMA treatment for 3months.The CAT score,age,smoking quantity,pulmonary function indices,body mass index (BMI),6-min walking distance (6MWD),modified medical British research council (mMRC)dyspnea scale,and the times of acute exacerbation of COPD (AECOPD)in previous one year were collected before and after treatment.The clinical characteristics analysis and correlation analysis were performed.Results The average age of the 81COPD patients was (66.27±8.52)years,with 88.89% being males and 85.19% having smoking history.The proportions of group A,B,C and D were 8.64%,30.86%,4.94%and 55.56% before treatment,respectively.The values of the forced expiratory volume in one second (FEV1),predicted amount as a percentage of FEV1(FEV1%Pred),forced vital capacity(FVC),predicted amount as a percentage of FVC (FVC%Pred),peak expiratory flow (PEF),predicted amount as a percentage of PEF(PEF%Pred),and 6MWD in CAT score≥10groups were significantly less than those in CAT score10 group(P0.05).The above parameters were not significantly different between patients with CAT score being 10-20,20- 30and≥30groups.mMRC scale and times of AECOPD in CAT score≥20groups were significantly higher than those in CAT score10group(P0.05).No significant difference in FEV1/FVC was found in different CAT score groups.The CAT score was significantly correlated with mMRC scale(pre-treatment r2=0.417,P0.001;post-treatment r2=0.19,P0.001), 6MWD (pre-treatment r2=0.320,P0.001;post-treatment r2=0.19,P0.001),pre-treatment FEV1(r2=0.177,P= 0.001 5),FEV1%Pred(r2=0.125,P=0.002),PEF(r2=0.164,P=0.002 4),PEF%Pred(r2=0.129,P=0.007 6),FVC (r2=0.098,P=0.021),FVC%Pred(r2=0.094,P=0.024),FEV1/FVC(r2=0.101,P=0.005 7),and AECOPD number (r2=0.059,P=0.028);and not correlated with the quantity of smoking (r2=0.041,P=0.083),BMI(r2=0.00,P= 0.89),and post-treatment FEV1(r2=0.01,P=0.22)or FEV1%Pred(r2=0.003,P=0.09).Conclusion COPD is prone to occur in the male smokers,with the highest proportion found in group D.CAT score has a good correlation with pre-and post -treatment mMRC scale and exercise capacity,suggesting it has a potential for predicting prognosis of COPD.