Association of body mass index with disease severity and prognosis in patients with non-cystic fibrosis bronchiectasis

The objective of this observational, multicenter study was to evaluate the association of body mass index (BMI) with disease severity and prognosis in patients with non-cystic fibrosis bronchiectasis. A total of 339 patients (197 females, 142 males) diagnosed with non-cystic fibrosis bronchiectasis by high-resolution computed tomography were classified into four groups: underweight (BMI<18.5 kg/m2), normal weight (18.5≤BMI<25.0 kg/m2), overweight (25.0≤BMI<30.0 kg/m2), and obese (BMI≥30.0 kg/m2). Clinical variables expressing disease severity were recorded, and acute exacerbations, hospitalizations, and survival rates were estimated during the follow-up period. The mean BMI was 21.90 kg/m2. The underweight group comprised 28.61% of all patients. BMI was negatively correlated with acute exacerbations, C-reactive protein, erythrocyte sedimentation rate, radiographic extent of bronchiectasis, and chronic colonization by P. aeruginosa and positively correlated with pulmonary function indices. BMI was a significant predictor of hospitalization risk independent of relevant covariates. The 1-, 2-, 3-, and 4-year cumulative survival rates were 94%, 86%, 81%, and 73%, respectively. Survival rates decreased with decreasing BMI (χ2=35.16, P<0.001). The arterial carbon dioxide partial pressure, inspiratory capacity, age, BMI, and predicted percentage of forced expiratory volume in 1 s independently predicted survival in the Cox proportional hazard model. In conclusion, an underweight status was highly prevalent among patients with non-cystic fibrosis bronchiectasis. Patients with a lower BMI were prone to developing more acute exacerbations, worse pulmonary function, amplified systemic inflammation, and chronic colonization by P. aeruginosa. BMI was a major determinant of hospitalization and death risks. BMI should be considered in the routine assessment of patients with non-cystic fibrosis bronchiectasis.

本项观察性多中心研究旨在评估体质量指数（body mass index，BMI）与非囊性纤维化支气管扩张症患者的疾病严重程度及预后的相关性。本研究共纳入339例经高分辨率计算机断层扫描确诊为非囊性纤维化支气管扩张症的患者（女性197例，男性142例），并将其分为四组：体质量过低组（体质量指数<18.5 kg/m²）、体质量正常组（18.5≤体质量指数<25.0 kg/m²）、体质量超重组（25.0≤体质量指数<30.0 kg/m²）及肥胖组（体质量指数≥30.0 kg/m²）。研究记录了反映疾病严重程度的临床变量，并估算了随访期间的急性加重次数、住院率及生存率。所有患者的平均体质量指数为21.90 kg/m²，其中体质量过低组占全部患者的28.61%。体质量指数与急性加重次数、C反应蛋白、红细胞沉降率、支气管扩张影像学范围及铜绿假单胞菌慢性定植呈负相关，与肺功能指标呈正相关。体质量指数是独立于相关协变量的住院风险显著预测因子。患者的1年、2年、3年及4年累积生存率分别为94%、86%、81%和73%，且生存率随体质量指数降低而下降（χ²=35.16，P<0.001）。在Cox比例风险模型（Cox proportional hazard model）中，动脉二氧化碳分压、吸气量、年龄、体质量指数及1秒用力呼气容积预计百分比均为生存率的独立预测因子。综上，体质量过低在非囊性纤维化支气管扩张症患者中患病率极高；体质量指数较低的患者更易出现更多次急性加重、更差的肺功能、更显著的全身炎症反应及铜绿假单胞菌慢性定植。体质量指数是住院及死亡风险的主要决定因素，应将其纳入非囊性纤维化支气管扩张症患者的常规评估流程。