Isoniazid prophylaxis: the importance of individual values.

To provide insight into the decision whether to use isoniazid prophylaxis in uncomplicated cases of positive tuberculin tests, the authors conducted a multicriteria decision analysis using the analytic hierarchy process. If reducing the chance of developing active tuberculosis is considered at least slightly more important than avoiding isoniazid-related side effects, isoniazid prophylaxis is the better strategy for all patients. If avoiding isoniazid-related side effects is considered at least slightly more important, no prophylaxis is the better strategy for all patients. If these two considerations are judged equally important, the better strategy depends on patient age, the anticipated effectiveness of isoniazid prophylaxis, and whether or not the patient is a recent tuberculin convertor. The tradeoff between avoiding active tuberculosis and avoiding isoniazid-related side effects is the most important factor in the decision regarding the proper management of patients with positive tuberculin tests. These results emphasize the importance of taking an individualized approach to the management of these patients.