Association between six-month and 12-month disease stability in chronic obstructive pulmonary disease: A multicenter...

BackgroundDisease stability (DS) has been proposed as a multidimensional measure of disease activity in chronic obstructive pulmonary disease, but its longitudinal behavior and the clinical relevance of early DS remain poorly characterized.ObjectivesTo characterize longitudinal DS and determine whether DS at 6 months is associated with DS at 12 months.DesignRetrospective multicenter cohort study conducted at four hospitals in Taiwan between January 2016 and December 2023.MethodsPatients with complete exacerbation records, spirometry data, and Chronic Airways Assessment Test (CAAT) data at baseline and at the 6- and 12-month assessments were included. DS was defined as the absence of moderate or severe exacerbations, <2-point worsening from baseline in CAAT score, and <100-mL decline in post-bronchodilator forced expiratory volume in one second. Multivariable logistic regression analyses were used to evaluate factors associated with DS and the association between 6- and 12-month DS.ResultsAmong 905 patients identified, 250 had complete longitudinal data and comprised the primary analytic cohort. DS was achieved by 114 patients (45.6%) at 6 months and 94 (37.6%) at 12 months. Among patients with and without 6-month DS, 68.4% and 11.8%, respectively, achieved 12-month DS. In the baseline multivariable model, prior moderate or severe exacerbations (adjusted odds ratio [aOR]: 0.25, 95% confidence interval [CI]: 0.12-0.53) and reliever use of ≥3 canisters/year (aOR: 0.50, 95% CI: 0.27-0.95) were associated with lower odds of 12-month DS. After additional adjustment for 6-month DS, achievement of 6-month DS was strongly associated with 12-month DS (aOR: 11.72, 95% CI: 5.67-24.22). This association remained consistent in the expanded ascertainable-outcome cohort (N = 544; aOR: 14.33, 95% CI: 7.30-28.14) and the multiple-imputation analysis of the full cohort (N = 905; aOR: 13.57, 95% CI: 8.39-21.93).ConclusionSix-month DS was strongly associated with subsequent DS and may represent a clinically relevant intermediate milestone for characterizing disease trajectory and identifying patients who may benefit from closer monitoring and management reassessment.