Figure 1
Associations between post-bronchodilator forced vital capacity/total lung capacity (FVC/TLCCT) quartiles at enrollment with dyspnea and health-related quality of life scores, chest CT % emphysema and % gas trapping, functional small airway disease, and 6-min walk test distance at baseline among smokers with Preserved Ratio Impaired Spirometry (PRISm; n = 1,131). Each panel in the figure represents a separate linear regression model with categorical post-bronchodilator FVC/TLCCT quartile as the main independent variable (exposure) with the “very high” quartile used as the reference category. The dependent variable (outcome) in each model was (A) modified Medical Research Council (mMRC) dyspnea score, (B) St. George’s Respiratory Questionnaire total score (SGRQ), (C) 6-minute walk test distance (6-MWT in meters), (D) % Emphysema, (E) % Gas trapping, and (F) functional small airways disease (PRMfSAD). All models were adjusted for the following co-variates: age, sex, race, smoking status, smoking pack-years, body mass index (BMI), history of asthma and congestive heart failure, and diabetes mellitus. FVC/TLCCT quartile is plotted on the x-axis while the regression coefficient (and 95% CI) for each category is plotted on the y-axis. *For % GT analysis, n = 936 subjects. †For PRMfsad data analysis, n = 932 subjects. #For 6-min walk test distance analysis, n = 1,121 subjects.
