[The decline of lung function and risk factors analysis in patients with coal workers'pneumoconiosis complicated with chronic obstructive pulmonary disease].

Objective: To investigate the decline of lung function and related risk factors in patients with coal workers' pneumoconiosis complicated with chronic obstructive pulmonary disease (COPD) . Methods: In December 2022, a retrospective analysis was performed for coal workers' pneumoconiosis complicated with COPD who were admitted to Hunan Prevention and Treatment Institute for Occupational Disease from 2017 to 2018, and the demographic data, lung function, blood eosinophil value (EOS), smoking status, occupational history, stage of pneumoconiosis, and treatment situation were collected until 2021. Multivariate Cox regression model was used to analyze the risk factor of lung function decline. Results: A total of 162 patients with coal workers' pneumoconiosis were included in this study, and the median follow-up time was 47 months. The lung function of the patients decreased to varying degrees during the follow-up period, and the annual decline of forced vital capacity (FVC) was 115.8 ml/year, percentage of predicted forced vital capacity (FVC%) was 2.9%/year, forced expiratory volume in one second (FEV(1)) was 99.6 ml/year, percentage of forced expiratory volume in one second (FEV(1)%) was 3.4%/year, ratio of forced expiratory volume in one second to forced vital capacity (FEV(1)/FVC) was 1.4%/year, diffusing capacity of the lungs for carbon monoxide (DLCO) was 0.32 mmol/min/KPa/year, and percentage of predicted diffusing capacity of the lungs for carbon monoxide (DLCO%) was 4.1%/year. The results of multivariate Cox regression analysis showed that dust exposure time (HR=1.04, 95%CI: 1.01-1.07), regular use of bronchodilators (HR=0.50, 95%CI=0.29-0.86), blood EOS (HR=1.39, 95%CI: 1.19-1.61), baseline FVC% (HR=1.02, 95%CI: 1.01-1.03, ) and cumulative cigarette smoking (HR=1.03, 95%CI: 1.02-1.05) were the influencing factor of lung function decline of patients with coal workers' pneumoconiosis complicated with COPD (P<0.05) . Conclusion: The lung function of patients with coal workers' pneumoconiosis complicated with COPD will gradually decline, and the baseline value of lung function, dust contact time, EOS, and smoking are the risk factors for the decline of lung function, and the regular use of bronchodilators is its protective factor.