In Reply. —
Dr S. S. Winkler and Mr D. S. Winkler suggest that hospital discharge summaries only occasionally include the diagnosis of pneumoconiosis when the patient has roentgenographic evidence of pneumoconiosis but pneumoconiosis is not the primary cause of hospitalization. If this is true, then this would be an additional reason why hospital discharge data do not pick up all diagnosed cases of pneumoconiosis. Despite our reliance on hospital discharge data for the source of cases for our silicosis surveillance system, we are well aware that discharge data are not allinclusive. Our efforts to encourage reports by individual physicians, although continuing, have not been extremely successful. Hospital discharge data do capture more cases than the current legally mandated federal surveillance system for occupational disease. What is particularly useful about hospital discharge data are their ready availability at relatively low cost.The underreporting on discharge summaries described in the Winklers'