Correlation between autopsy findings for chronic obstructive airways disease and in-life disability in South African gold miners

Abstract

Objectives: In South Africa chronic obstructive airway disease (COAD), which could be due to working in a dusty atmosphere in scheduled mines or works, is a compensatable disease. Miners are compensated for in-life respiratory disability and for findings at autopsy of COAD, which includes emphysema, bronchitis assessed by mucus gland hyperplasia in the main bronchus, and bronchiolitis assessed by goblet cell metaplasia. The question arises as to whether the autopsy findings correlate with in-life impairment. The objectives of the study were: (1) to determine whether autopsy COAD outcomes relate to lung function and to respiratory symptoms and signs; and (2) to quantify the individual contributions of emphysema, bronchiolitis and bronchitis to lung function impairment. Methods: On 724 gold miners, pathological findings of COAD – emphysema, bronchitis and bronchiolitis – were related to lung function measurements and respiratory symptoms and signs observed within 5 years prior to death. Results: Emphysema diagnosed at autopsy was the main determinant of airflow impairment. The emphysema score categories 0–5, 5–35, 35–65 and >65 were associated with decreased forced expiratory volume in 1 s, expressed as percentage predicted (FEV₁%) as follows: 78.8%, 66.2%, 52.0% and 46.0%, respectively. The score was also associated with increasing frequency of dyspnoea. After adjustment for emphysema, the bronchitis and bronchiolitis were not related to significant lung function loss, and in subjects without emphysema, the presence of moderate or marked bronchitis was associated with a mild impairment only. Bronchitis at autopsy was associated with increased frequency of rhonchi, sputum and cough, whereas bronchiolitis was associated with increased sputum only. Silicosis found at autopsy was associated with some obstructive and restrictive lung function impairment. Tobacco smoking was associated with all the COAD outcomes.