Abstract
Background
Methods
Results
Figures and Tables
Figure 1
Flow chart illustrating the disposition of the patients who were enrolled and analyzed in the study. COPD: chronic obstructive pulmonary disease; KOLD: Korean Obstructive Lung Disease; LAMA: long-acting muscarinic antagonists; LABA: long-acting β2-agonists; ICS: inhaled corticosteroid.
![trd-79-22-g001](/upload/SynapseData/ArticleImage/0003trd/trd-79-22-g001.jpg)
Figure 2
Mean rate of change from baseline in pre-bronchodilator forced expiratory volume in 1 second (FEV1) during follow-up. (A) The decline in lung function in the step-down group after the index time was significantly accelerated compared to that in the triple group. (B) The maintained step-down and step-up groups had a significantly accelerated decline in lung function after the index time compared to the triple group.
![trd-79-22-g002](/upload/SynapseData/ArticleImage/0003trd/trd-79-22-g002.jpg)
Figure 3
Kaplan-Meier curves for the estimated probability of chronic obstructive pulmonary disease exacerbations. (A) The step-down group had a significantly longer time to the first exacerbation than the triple group. (B) The maintained step-down group had a significantly longer time to the first exacerbation than the triple group and also than the step-up group.
![trd-79-22-g003](/upload/SynapseData/ArticleImage/0003trd/trd-79-22-g003.jpg)
Table 1
Demographic and baseline clinical characteristics at the index time
![trd-79-22-i001](/upload/SynapseData/ArticleImage/0003trd/trd-79-22-i001.jpg)
Values are presented as the mean±standard deviation unless otherwise indicated.
p-values were generated by Student's t tests for continuous variables and chi-squared tests for categorical variables.
MMRC: modified Medical Research Council; 6MWD: 6-minute walk distance; SGRQ: St. George's Respiratory Questionnaire; CT, computed tomography; IT: index time; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; DLco: diffusing capacity of the lung for carbon monoxide; IC: inspiratory capacity; RV: residual volume; TLC: total lung capacity.
Table 2
Changes in COPD variables after the index time
![trd-79-22-i002](/upload/SynapseData/ArticleImage/0003trd/trd-79-22-i002.jpg)
Values are presented as the mean±standard deviation.
p-values were obtained by analysis of covariance (ANCOVA) for continuous variables and logistic regression analysis for categorical variables. All analyses were adjusted for baseline FEV1, gender, age, smoking status, computed tomography emphysema index, and the time intervals when the variables were measured.
*"Just before the IT" refers to the most recent results before the IT and "Just after the IT" refers to the first results collected after the IT. MMRC was measured every 3 months, pre-bronchodilator FEV1 was measured every 6 months, and IC, RV/TLC, 6MWD, SGRQ total score, and exacerbation/year were measured every 12 months.
COPD: chronic obstructive pulmonary disease; IT: index time; FEV1: forced expiratory volume in 1 second; IC: inspiratory capacity; RV: residual volume; TLC: total lung capacity; MMRC: modified Medical Research Council; 6MWD: 6-minute walk distance; SGRQ: St. George's Respiratory Questionnaire.
Table 3
Changes in variables after the index time in the maintained step-down and step-up groups
![trd-79-22-i003](/upload/SynapseData/ArticleImage/0003trd/trd-79-22-i003.jpg)
Values are presented as the mean±standard deviation.
p-values were obtained by analysis of covariance (ANCOVA) for continuous variables and logistic regression analysis for categorical variables. All analyses were adjusted for baseline FEV1, gender, age, smoking status, emphysema index, and the time intervals when the variables were checked.
*"Just before the IT" refers to the most recent results before the IT, and "Just after the IT" refers to the most recent results after the IT. MMRC was measured every 3 months, pre-bronchodilator FEV1 was measured every 6 months, and IC, RV/TLC, 6MWD, SGRQ total score, and exacerbation/yr were measured every 12 months.
IT: index time; FEV1: forced expiratory volume in 1 second; IC: inspiratory capacity; RV: residual volume; TLC: total lung capacity; MMRC: modified Medical Research Council; 6MWD: 6-minute walk distance; SGRQ: St. George's Respiratory Questionnaire.