Validation of autopsy data for epidemiologic studies of coal miners

South Africa has one of the largest miner autopsy databases, PATHAUT, dating back to 1925. The diagnoses recorded on this database have never been evaluated for coal miners. The objective was to determine the validity of the autopsy diagnoses for coal workers, specifically bronchitis, silicosis, tuberculosis, coal workers' pneumoconiosis and emphysema, from 1975 to 1997.

Three pathologists experienced in miner respiratory pathology conducted the review. They were blinded to employment and medical histories as well as to previous pathological diagnoses on PATHAUT and reviewed 28 coal miners with mixed mining exposures, and 31 cases with exclusive coal mine exposure--all selected randomly. The reviewers' independent and consensus diagnoses were compared to PATHAUT. An additional 31 cases with available whole mount sections were reviewed for the diagnosis of emphysema. Kappa statistics were used to determine degrees of agreement among reviewers and between reviewers and PATHAUT.

There was good to excellent agreement between the reviewers and PATHAUT for silicosis, tuberculosis, and pneumoconiosis that had progressed beyond the stage of macules, among the mixed and exclusive coal exposure cases. There was good to excellent inter-reviewer agreement for all diseases except bronchitis (agreement=fair to very good). For emphysema, there was good to very good inter-reviewer agreement but fair agreement with PATHAUT.

This, the first systematic review of PATHAUT autopsy diagnoses made on coal workers, showed that PATHAUT can be used with confidence to establish a diagnosis of moderate to severe grades of coal workers' pneumoconiosis. The grade of emphysema recorded on PATHAUT could be used for epidemiological purposes, when whole mount sections have been prepared.