Study on changes of pulmonary function in patients with pneumoconiosis in three years

Objective: To investigate the characteristics of pulmonary function changes and its possible influencing factors in patients with pneumoconiosis. Methods: In December 2019, pneumoconiosis patients hospitalized in four departments of occupational diseases in Hunan Occupational Disease Prevention and Control Hospital from December 2015 to December 2016 were selected as subjects. Lung function including forced vital capacity (FVC) , FVC%, forced expiratory volume in one second (FEV1) , FEV1%, forced expiratory volume in one second / forced vital capacity (FEV1/FVC) , diffusion capacity of the lung foe carbon monoxide% (DLCO%) 、maximal expiratory rlow 75% (MEF75%) , maximal expiratory rlow 50% (MEF50%) and maximal expiratory rlow 25% (MEF25%) were tested, and collect their age, occupation history, smoking history and Chronic Obstructive Pulmonary Disease Self Rating Questionnaire (CAT) score. They were followed up after 3 years to analyze the 3-year decline rates of lung function indicators and their relationship with stage of pneumoconiosis, age, smoking index, baseline values of lung function and CAT score. Results: 265 cases were studied effectively. After 3 years, the values of 9 lung function indicators of pneumoconiosis patients were significantly lower than those of 3 years ago (P<0.05) . The decline rates of FEV1%, FEV1/FVC, MEF75%, MEF50% and MEF25% were positively correlated with the stage of pneumoconiosis (r=0.250, 0.290, 0.219, 0.280, 0.141, P<0.05) . The decline rates of FEV1% and MEF75% were positively correlated with smoking index (r=0.148, 0.152, P<0.05) . The decline rates of DLCO% and MEF25% were positively correlated with the baseline value of initial pulmonary function (r=0.276, 0.153, P<0.05) , while the decline rates of FEV1%, FEV1/FVC and MEF50% were negatively correlated with the baseline values of initial pulmonary function (r=-0.215, -0.146, -0.214, P<0.05) . The decline rates of FVC%, FEV1%, MEF75% and MEF50% were positively correlated with the changes of CAT scores (r=0.147, 0.208, 0.210, 0.196, P<0.05) . Logistic regression analysis showed that old age and high initial value of DLCO% were the risk factor for the decline of DLCO% (OR=1.105、1.078, P<0.05) .High smoking index was the risk factors for the decline of MEF75% (OR=1.016, P<0.05) . High stage and the increase of CAT score were the risk factors for the decline of MEF50% (OR=1.548, 1.162, P<0.05) . High initial value of MEF25% was the risk factor for the decline of MEF25% (OR=1.010, P<0.05) . Conclusion: The pulmonary function index of pneumoconiosis patients declined significantly in 3 years. The stage of pneumoconiosis, age, smoking index and degree of pulmonary function damage were related to the decline rate of pulmonary function.