Association Between Expiratory Central Airway Collapse and Respiratory Outcomes Among Smokers.

摘要: Importance Central airway collapse greater than 50% of luminal area during exhalation (expiratory central [ECAC]) is associated with cigarette smoking and chronic obstructive pulmonary disease (COPD). However, its prevalence clinical significance are unknown. Objective To determine whether ECAC respiratory morbidity in smokers independent underlying lung disease. Design, Setting, Participants Analysis paired inspiratory-expiratory computed tomography images from a large multicenter study (COPDGene) current former 21 centers across the United States. were enrolled January 2008 to June 2011 followed up longitudinally until October 2014. Images initially screened using quantitative method detect at least 30% reduction minor axis tracheal diameter inspiration end-expiration. From this sample screen-positive scans, cross-sectional trachea was measured manually 3 predetermined levels (aortic arch, carina, bronchus intermedius) confirm (>50% area). Exposures Expiratory collapse. Main Outcomes Measures The primary outcome baseline quality life (St George’s Respiratory Questionnaire [SGRQ] scale 0 100; 100 represents worst health status; minimum clinically important difference [MCID], 4 units). Secondary outcomes measures dyspnea (modified Medical Research Council [mMRC] 4; worse dyspnea; MCID, 0.7 units), 6-minute walk distance (MCID, 30 m), exacerbation frequency (events per person-years) on longitudinal follow-up. Results included 8820 participants without COPD (mean age, 59.7 [SD, 6.9] years; 4667 [56.7%] men; 4559 [51.7%] active smokers). 5% (443 cases). Patients compared those had SGRQ scores (30.9 vs 26.5 units; P  = .30), after adjustment for sex, race, body mass index, forced expiratory volume first second, pack-years smoking, emphysema. On follow-up (median, 4.3 [IQR, 3.2-4.9] years), increased total exacerbations (58 35 events person-years; incidence rate ratio [IRR], 1.49 [95% CI, 1.29-1.72]; Conclusions Relevance In analysis smokers, presence life. Further studies needed assess long-term associations outcomes.