Potential pre-COPD indicators in association with COPD development and COPD prediction models in Chinese: a prospective cohort study

Lung injury might take place before chronic obstructive pulmonary disease (COPD) occurs. A clearer definition of “pre-COPD” based on the effects of potential indicators on increasing risk of COPD development and a prediction model involving them are lacking. A total of 3526 Chinese residents without COPD aged 40 years or older derived from the national cross-sectional survey of COPD surveillance in 2014–2015 were followed up for a mean of 3.59 years. We examined the associations of chronic bronchitis, preserved ratio impaired spirometry (PRISm), low peak expiratory flow (PEF), spirometric small airway dysfunction (sSAD), low maximal mid-expiratory flow (MMEF), low forced expiratory flow 50% of pulmonary volume (FEF50), and low FEF75 with subsequent COPD and constructed a prediction model with LASSO-Cox regression. 235 subjects in the cohort developed COPD during the follow-up. Subjects with PRISm, low PEF, sSAD, low MMEF, low FEF50, and low FEF75 had an increased risk of developing COPD (adjusted hazard ratio [HR] ranging from 1.57 to 3.01). Only chronic bronchitis (HR 2.84 [95% CI 1.38–5.84] and 2.94 [1.43–6.04]) and sSAD/low MMEF (HR 2.74 [2.07–3.61] and 2.38 [1.65–3.43]) showed effects independent of the other indicators and their concurrence had the strongest effect (HR 5.89 and 4.80). The prediction model including age, sex, low MMEF, low FEF50, and indoor exposure to biomass had good performance both internally and temporally. The corrected C-index was 0.77 (0.72–0.81) for discrimination in internal validation. For temporal validation, the area under the receiver operating characteristic curve was 0.73 (0.63–0.83). Good calibration was indicated in plot for internal validation and by Hosmer–Lemeshow test for temporal validation. Individuals with concurrent chronic bronchitis and sSAD/low MMEF indicating pre-COPD optimally require more high attention from physicians. Our prediction model could serve as a multi-dimension tool to predict COPD comprehensively. The Ministry of Finance and the Ministry of Science and Technology of the People's Republic of China and the National Natural Science Foundation of China. 在慢性阻塞性肺疾病(chronic obstructive pulmonary disease, COPD)出现前, 肺损伤可能已经发生。目前尚缺乏依据潜在指标对升高COPD发生风险的影响而产生的更明确的"慢阻肺前期"的定义, 以及包含这些潜在指标的慢阻肺发病预测模型。 本研究基于2014–2015年中国居民慢阻肺监测横断面调查, 对3526名40岁及以上的非慢阻肺居民进行了平均3.59年的随访；旨在分析慢性支气管炎、保留比值的肺功能损伤 (preserved ratio impaired spirometry, PRISm)、低呼气峰流速 (peak expiratory flow, PEF)、小气道功能障碍 (spirometric small airway dysfunction,