Objective To study the predictive value of inspiratory capacity (IC) and total lung capacity (TLC) on acute exacerbation of patients with chronic obstructive pulmonary disease (COPD). Methods The in-patients due to acute exacerbation of COPD (AECOPD) from February 2017 to March 2019 were recruited in the study. Research data were collected during the recovery period and one year follow-up , and the patients were divided into two groups according to whether there was another acute exacerbation. Results A total of 372 patients were included in the study. In the patients with acute exacerbation, the age and TLC as a percentage of the expected value (TLC%pred) were higher, while IC as a percentage of the expected value (IC%pred) and the ratio of IC and TLC (IC/TLC) were lower. Univariate analysis revealed that IC/TLC≤25% was a significant predictor of acute exacerbation (P<0.001) after the AECOPD patients were discharged. Multivariable analysis revealed age (OR=1.25, 95%CI 1.17 to 1.44, P<0.001) and IC/TLC≤25% (OR=1.68, 95%CI 1.36 to 2.07, P<0.001) were independent risk factors of AECOPD.Conclusions Decreased IC/TLC significantly correlates with poor prognosis of COPD. IC/TLC≤25% is an independent risk factor for acute exacerbation.
