PURPOSE: The diagnosis of tuberculosis remains controversial between clinicians and public health officers. Public health officials fear to treat too many patients; clinicians fear that truly diseased will be denied treatment. We wondered whether an analysis of the treatment threshold could help making the often intuitive decision to treat smear-negative cases more evidence based.
METHODS: Eighteen clinicians and 10 public health specialists were asked for an intuitive estimate of their treatment threshold for tuberculosis and of key determinant factors for this threshold: the magnitude and subjective weight of mortality and morbidity due to both the disease and the treatment and risk and cost of the latter. With these factors, the authors calculated treatment thresholds and compared them to the intuitive thresholds of the interviewees. A prescriptive threshold was calculated based on literature data, omitting cost and subjective factors.
RESULTS: The median overall intuitive treatment threshold was 52.5%, the calculated 11.9%, and the prescriptive 2.7%. For 2 factors, public health officers provided significantly lower values than clinicians: cost of treatment (median = 20 dollars v. 300 dollars; U = 2.5; P = 0.0002); cost of life (median = 500 dollars v. 5000 dollars; U = 17.5; P = 0.009).
CONCLUSION: These results suggest that clinicians and public health officers estimate wrongly the threshold even when using their own subjective estimate of influencing factors. Omitting treatment cost and subjective weight of provoked harm can result in a very low threshold. Sound training in threshold principles and providing tools to correctly assess data might help in making better decisions in tuberculosis in developing countries.