Effect of twice daily inhaled albuterol on cardiopulmonary exercise outcomes, dynamic hyperinflation, and symptoms in secondhand tobacco-exposed persons with preserved spirometry and air trapping: a randomized controlled trial.

BACKGROUND: In tobacco-exposed persons with preserved spirometry (active smoking or secondhand smoke [SHS] exposure), air trapping can identify a subset with worse symptoms and exercise capacity. The physiologic nature of air trapping in the absence of spirometric airflow obstruction remains unclear. The aim of this study was to examine the underlying pathophysiology of air trapping in the context of preserved spirometry and to determine the utility of bronchodilators in SHS tobacco-exposed persons with preserved spirometry and air trapping. METHODS: We performed a double-blinded placebo-controlled crossover randomized clinical trial in nonsmoking individuals at risk for COPD due to exposure to occupational SHS who had preserved spirometry and air trapping defined as either a residual volume-to-total lung capacity ratio (RV/TLC) > 0.35 or presence of expiratory flow limitation (EFL, overlap of tidal breathing on maximum expiratory flow-volume loop) on spirometry at rest or during cardiopulmonary exercise testing (CPET). Those with asthma or obesity were excluded. Participants underwent CPET at baseline and after 4-week trials of twice daily inhalation of 180 mcg of albuterol or placebo separated by a 2-week washout period. The primary outcome was peak oxygen consumption (VO2) on CPET. Data was analyzed by both intention-to-treat and per-protocol based on adherence to treatment prescribed. RESULTS: Overall, 42 participants completed the entire study (66 ± 8 years old, 91% female; forced expiratory volume in 1 s [FEV1] = 103 ± 16% predicted; FEV1 to forced vital capacity [FVC] ratio = 0.75 ± 0.05; RV/TLC = 0.39 ± 0.07; 85.7% with EFL). Adherence was high with 87% and 93% of prescribed doses taken in the treatment and placebo arms of the study, respectively (P = 0.349 for comparison between the two arms). There was no significant improvement in the primary or secondary outcomes by intention-to-treat or per-protocol analysis. In per-protocol subgroup analysis of those with RV/TLC > 0.35 and ≥ 90% adherence (n = 27), albuterol caused an improvement in peak VO2 (parameter estimate [95% confidence interval] = 0.108 [0.014, 0.202]; P = 0.037), tidal volume, minute ventilation, dynamic hyperinflation, and oxygen-pulse (all P < 0.05), but no change in symptoms or physical activity. CONCLUSIONS: Albuterol may improve exercise capacity in the subgroup of SHS tobacco-exposed persons with preserved spirometry and substantial air trapping. These findings suggest that air trapping in pre-COPD may be related to small airway disease that is not considered significant by spirometric indices of airflow obstruction.

Spirometric obstruction and tobacco exposure among male Turkish nursing home residents.

Spirometric obstruction is a prevalent problem in older adults and related to life-style risk factors. Symptoms related to chronic-obstructive-pulmonary-disease (COPD) are also prevalent symptoms with diverse etiologies - not limited to pulmonary obstruction. Older adults may have unrecognized airway obstruction due to functional limitations or symptoms mis-attributed to age/other co-morbidities. Therefore, spirometric obstruction may clinically be over/under diagnosed. Over last few decades, the burden of smoking-related diseases has increased in older adults. Additional evidence regarding older adults is required. We aimed to study frequency of spirometric obstruction, its over/under diagnosis and tobacco exposure in a group of male nursing-home residents. For spirometric obstruction diagnosis, two different thresholds [(fixed value: 0.70) versus (age-corrected value: 0.65 in residents >65 years of age)] were compared for better clinical practice. One hundred and three residents with 71.4 ± 6.3 years-of-age included. Spirometric obstruction prevalences were 39.8 and 29.1% with fixed and age-corrected FEV1/FVC thresholds, respectively. Age-corrected FEV1/FVC threshold underdiagnosed COPD in 1.9% while fixed threshold overdiagnosed spirometric obstruction in 8.7%. Active smokers were 64.1%, ex-smokers 23.3% and non-smokers 12.6%. Our study suggests high prevalences of spirometric obstruction and smoking in male nursing-home residents in Turkey. We suggest the use of age-corrected FEV1/FVC threshold practicing better than the use of fixed FEV1/FVC threshold in this patient group.