Survival analysis of 589 pneumoconiosis patients diagnosed in past 52 years

Objective To investigate the survival status and influencing factors of pneumoconiosis patients in a coal mine in Dazhou City.

Methods All 589 patients with pneumoconiosis diagnosed during 1965 to 2017 were investigated. The Kaplan-Meier method and life table method were used for survival analysis, and Cox regression model was used to analyze the factors affecting the survival time.

Results Among 589 cases of pneumoconiosis, 185 deaths were reported in this coal mine with a case fatality rate of 31.41% and median survival time was 31.47 years. The fatality rate gradually decreased (P < 0.01) and median survival time became longer (P < 0.01)with the years. The cumulative survival rate for pneumoconiosis cases decreased with increasing survival time. Compared with coal workers' pneumoconiosis, the patients with silicosis had an increased risk of reduced survival time (OR=1.424, P < 0.05). Compared with the cases with stage Ⅰ, patients with stage Ⅲ or Ⅱ had an increased risk of reduced survival time (OR=6.210 or 1.475, P < 0.05). Patients complicated with tuberculosis had an increased risk of reduced survival time compared with those without tuberculosis (OR=1.570, P < 0.05). Compared with the non-smokers, patients with smoking history had an increased risk of reduced survival time (OR=1.601, P < 0.05). Compared with patients with exposure time lower than 10 years, patients with exposure time 10-20 years or longer than 20 years had an increased risk of reduced survival time (OR=5.013 or 7.585, P < 0.05).Compared with patients with the onset age lower 30 years old, patients with the onset age of 30-39, 40-49, 50-59 and older than 59 years old had increased risk of reduced survival time (ORs varied from 3.906 to 86.572, P < 0.05).

Conclusion The death risk of pneumoconiosis patients was related to the dust types and exposure time, the pneumoconiosis stage, smoking behavior, the complication of tuberculosis, and age of onset. The risk factors should be effectively controlled to improve the life quality and prolong the life span of pneumoconiosis patients.