Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
Division of Infection, Immunity and Respiratory Medicine, The University of Manchester and Manchester University NHS Foundation Trust, Manchester, United Kingdom.
Respiration. 2020;99(11):943-953. doi: 10.1159/000511022. Epub 2020 Dec 2.
Low body mass index (BMI) is an important prognostic factor in chronic obstructive pulmonary disease (COPD). However, the prognostic value of longitudinal BMI change in COPD has not been well studied.
We aimed to evaluate the association between longitudinal change of BMI and prognosis of COPD in Korean COPD cohort.
This study was conducted in a prospective Korean Obstructive Lung Disease (KOLD) cohort where COPD patients were recruited on an outpatient basis at 17 hospitals in South Korea. Annual BMI was measured over a period of 3 years or more. All patients were categorized into underweight (UW), normal weight (NW), and overweight (OW) groups by BMI. Clinical characteristics and outcomes including exacerbation and mortality were compared based on initial BMI grade and longitudinal change of BMI.
This analysis included 537 COPD patients (mean age = 67.4 ± 7.9 years, male = 97.0%, mean BMI = 23.0 ± 3.1) of KOLD cohort. The proportions of UW, NW, and OW groups were 6.9% (n = 37), 68.9% (n = 370), and 24.2% (n = 130) respectively. The UW group showed lower forced expiratory volume in 1 s (FEV1) (p < 0.001), shorter 6-minute walk distance (p < 0.001), higher modified Medical Research Council score (p = 0.002), higher St. George Respiratory Questionnaire score (p < 0.001), higher emphysema index (p < 0.001) and air-trapping index (p < 0.001), and more frequent (p < 0.001) and severe exacerbations (p = 0.003). Multivariable analyses demonstrated that decrease of BMI (hazard ratio [HR] = 0.786, p = 0.038) and the descent of BMI group (HR = 3.167, p = 0.016) at 3-year follow-up along with age, initial BMI, post-bronchodilator FEV1, and severe exacerbations were significantly associated with mortality.
This study demonstrated that BMI decrease during follow-up was independently associated with exacerbation and higher mortality of COPD, suggesting BMI reduction in COPD should be carefully managed.
低体重指数（BMI）是慢性阻塞性肺疾病（COPD）的一个重要预后因素。然而，COPD 患者 BMI 纵向变化与预后的关系尚未得到很好的研究。
我们旨在评估韩国 COPD 队列中 BMI 纵向变化与 COPD 预后的关系。
这项研究在一项前瞻性韩国阻塞性肺疾病（KOLD）队列中进行，该队列在韩国 17 家医院的门诊基础上招募 COPD 患者。在 3 年或更长时间内测量每年的 BMI。根据 BMI 将所有患者分为消瘦（UW）、正常体重（NW）和超重（OW）组。根据初始 BMI 等级和 BMI 的纵向变化比较临床特征和结局，包括加重和死亡率。
这项 KOLD 队列的分析包括 537 名 COPD 患者（平均年龄=67.4±7.9 岁，男性=97.0%，平均 BMI=23.0±3.1）。UW、NW 和 OW 组的比例分别为 6.9%（n=37）、68.9%（n=370）和 24.2%（n=130）。UW 组的用力呼气量 1 秒率（FEV1）较低（p＜0.001），6 分钟步行距离较短（p＜0.001），改良医学研究委员会评分较高（p=0.002），圣乔治呼吸问卷评分较高（p＜0.001），肺气肿指数（p＜0.001）和空气潴留指数（p＜0.001）较高，且更频繁（p＜0.001）和严重加重（p=0.003）。多变量分析表明，BMI 下降（HR=0.786，p=0.038）和 BMI 组下降（HR=3.167，p=0.016）与年龄、初始 BMI、支气管扩张剂后 FEV1 和严重加重一起在 3 年随访时与死亡率显著相关。
本研究表明，随访期间 BMI 下降与 COPD 加重和更高的死亡率独立相关，提示 COPD 患者 BMI 下降应谨慎管理。
