Lung function decline in subjects with and without COPD in a population-based cohort in Latin-America

BackgroundLung-function decline is one of the possible mechanisms leading to Chronic Obstructive Pulmonary Disease (COPD).MethodsWe analyzed data obtained from two population-based surveys of adults (n = 2026) conducted in the same individuals 5–9 years (y) after their baseline examination in three Latin-American cities. Post BronchoDilator (postBD) FEV1 decline in mL/y, as %predicted/y (%P/y) and % of baseline/y (%B/y) was calculated and the influence of age, gender, BMI, baseline lung function, BD response, exacerbations rate evaluated using multivariate models.ResultsExpressed in ml/y, the mean annual postBD FEV1 decline was 27 mL (0.22%P, 1.32%B) in patients with baseline COPD and 36 (0.14%P, 1.36%B) in those without. Faster decline (in mL/y) was associated with higher baseline lung function, with significant response to bronchodilators, older age and smoking at baseline, also in women with chronic cough and phlegm, or ≥2 respiratory exacerbations in the previous year, and in men with asthma.ConclusionsLung function decline in a population-based cohort did not differ in obstructed and non-obstructed individuals, it was proportional to baseline FEV1, and was higher in smokers, elderly, and women with respiratory symptoms.研究背景：肺功能下降是导致慢性阻塞性肺疾病（Chronic Obstructive Pulmonary Disease，COPD）的潜在发病机制之一。研究方法：本研究对两项基于人群的成人调查数据进行了分析，共纳入2026名受试者。所有受试者均在基线检查完成后的5~9年间，于3个拉丁美洲城市接受了随访调查。本研究计算了支气管舒张后（post BronchoDilator，postBD）一秒用力呼气容积（Forced Expiratory Volume in 1 Second，FEV1）的年下降量（单位：mL/y），以及以预测值百分比计的年下降率（%P/y）和以基线值百分比计的年下降率（%B/y）；并采用多因素回归模型分析了年龄、性别、体重指数（Body Mass Index，BMI）、基线肺功能、支气管舒张反应、呼吸道急性加重频率对FEV1年下降率的影响。研究结果：以mL/y为单位时，基线确诊COPD的受试者其年平均postBD FEV1下降量为27 mL（0.22%P，1.32%B），而非COPD受试者则为36 mL（0.14%P，1.36%B）。FEV1年下降速度更快（以mL/y计）与基线时更高的肺功能水平、显著的支气管舒张反应、高龄及吸烟状态相关；此外，伴有慢性咳嗽咳痰的女性、既往1年呼吸道急性加重≥2次的女性，以及合并哮喘的男性，其FEV1年下降速度也更快。研究结论：基于该人群队列的分析显示，气道阻塞与非气道阻塞个体的肺功能下降速率无显著差异；肺功能下降幅度与基线FEV1水平呈正比，且在吸烟者、老年人以及伴有呼吸道症状的女性中更为显著。