Utility of the CAT in the therapy assessment of COPD exacerbations in China

BACKGROUND: Chronic obstructive pulmonary disease (COPD) exacerbations are accompanied with increased systemic inflammation, which accelerate the pulmonary function injury and impair the quality of life. Prompt and effective treatments for COPD exacerbations slow down the disease progression, but an objective instrument to assess the efficacy of the treatments following COPD exacerbations is lacking nowadays. The COPD Assessment Test (CAT) is an 8-item questionnaire designed to assess and quantify health status and symptom burden in COPD patients. We hypothesize that the change in CAT score is related to the treatment response following COPD exacerbations. METHODS: 78 inpatients with clinician-diagnosed acute exacerbation of COPD (AECOPD) completed the CAT, St George’s Respiratory Questionnaire (SGRQ) and modified Medical Research Council (mMRC) Dyspnea Scale both at exacerbation and the 7th day of therapy, and a subgroup of 39 patients performed the pulmonary function test. Concentrations of serum C-reactive protein (CRP) and plasma fibrinogen were assayed at the same time. Correlations between the CAT and other measurements were examined. RESULTS: After 7 days’ therapy, the CAT and SGRQ scores, mMRC grades, as well as the concentrations of CRP and fibrinogen all decreased significantly (P < 0.001). Meanwhile, the FEV1% predicted had a significant improvement (P < 0.001). The CAT scores were significantly correlated with concurrent concentrations of CRP and fibrinogen, SGRQ scores, FEV1% predicted and mMRC grades (P < 0.05). The change in CAT score was positively correlated with the change of CRP (r = 0.286, P < 0.05), SGRQ score (r = 0.725, P < 0.001) and mMRC grades (r = 0.593, P < 0.001), but not with fibrinogen (r = 0.137, P > 0.05) or FEV1% predicted (r = -0.101, P > 0.05). No relationship was found between the changes of SGRQ score and CRP and fibrinogen (P>0.05). CONCLUSIONS: The CAT is associate with the changes of systemic inflammation following COPD exacerbations. Moreover, the CAT is responsive to the treatments, similar to other measures such as SGRQ, mMRC dyspnea scale and pulmonary function. Therefore, the CAT is a potentially useful instrument to assess the efficacy of treatments following COPD exacerbations.