We compared clinical characteristics of COPD patients according to symptom variability and evaluated the effect of symptom variability during the first year of enrollment on clinical outcomes of COPD.
We analyzed COPD patients’ data from the Korean Obstructive Lung Disease (KOLD) cohort. Symptom variability was defined based on the value of standard deviation (SD) of mMRC scores obtained every 3 months during the follow-up period of the first year. Patients were divided into 2 groups: the consistent (SD of mMRC scores =0) and variable (SD of mMRC scores >0) groups. Clinical characteristics and outcomes were compared in terms of symptom variability.
A total of 407 patients were included in the analysis. Patient age was 67.2 years and 97.8% of the subjects were male. Initial mMRC was 1.5 and the SD of mMRC scores during the first year was 0.5. There were 137 subjects (33.7%) in the consistent group and 270 (66.3%) in the variable group. The variable group showed a lower FEV 1 ( P=0.019) and a higher mMRC score ( P=0.001). The annual incidence of acute exacerbation of COPD (AE-COPD) tended to be higher in the variable group ( P=0.078) and that of severe AE-COPD was higher in the variable group than in the consistent group ( P=0.002). The variable group showed a higher proportion of annual exacerbators ( P=0.001) and frequent exacerbators ( P=0.017). In multivariate logistic regression analysis, the variable group was significantly associated with annual exacerbators (OR =1.963, P=0.011) and frequent exacerbators (OR =2.090, P=0.055).