Directly observed preventive therapy: Turning the tide against tuberculosis

Objective: To compare compliance between directly observed preventive therapy and daily treatment for students with inactive (class II) tuberculosis. Design: Cohort analytic study and cost-effectiveness analysis. Students found to be positive for purified protein derivative and having no abnormal chest x-ray films on mandated screening were advised to have prophylactic treatment with isoniazid. Treatment was either directly observed in the school health clinic or provided as daily therapy by the Department of Health. Treatment completion, age, sex, ethnicity, and recent immigration were compared between the 2 treatment groups. Setting: A school-based clinic at an inner-city New York, NY, high school. Results: In 1993, 864 students were screened. The positive purified protein derivative rate was 19.3%. All 161 students had negative findings on chest x-ray films. Of the students, 105 (65.2%) were enrolled in the school-based clinic directly observed preventive therapy program, 22 were referred to the Department of Health for daily therapy, and 34 were excluded from the study before treatment. The 2 treatment groups did not differ in composition. Completion of therapy in the directly observed preventive therapy group (87.6%) was significantly greater than that in the daily therapy group (50%) (P=.001, χ²=11.8) and that reported in the literature for programs other than directly observed preventive therapy (30%-70%). Directly observed preventive therapy was administered by existing personnel without additional expenditure. Conclusion: Directly observed preventive therapy is an effective strategy that should be used in the school clinic setting to increase compliance with prophylactic treatment for tuberculosis.