SILICOTUBERCULOSIS - LONG-TERM OUTCOME AFTER SHORT-COURSE CHEMOTHERAPY

Setting: A medical facility for approximately 90 000 gold miners emplo yed on 24 South African gold mines. Objective: To establish the long-t erm risk attributable to silicosis of relapse from pulmonary tuberculo sis treated,vith short-course chemotherapy. Design: A consecutive samp le of gold miners with pulmonary tuberculosis allocated to receive rif ampicin, isoniazid, pyrazinamide and streptomycin given on weekdays fo r 5 months. Radiographs were assessed at the time of diagnosis for the presence of silicosis. All of the men were followed for at least 5 ye ars after completing their treatment, or until they left mine service or suffered a relapse of tuberculosis. Results: The sample included 54 9 men of whom 167 had silicosis. The incidence density for relapse in silicosis was 1.55 (95% CI 0.97, 2.48) times that for the men without silicosis. There was no difference in the pattern of relapse over time between the two groups: the mean period to relapse in the men with si licosis was 2.6 years (SD 1.89 years) and for the men without silicosi s was 3.1 years (SD 2.23 years) (P = 0.6). Conclusion: Silicosis cause s a small increase in the risk of relapse of tuberculosis. Relapses in both groups were not confined to the first 2 years after completion o f treatment.