Research Summary: Natural History of Tuberculosis: Duration and Fatality of Untreated Pulmonary Tuberculosis in HIV Negative Patients: A Systematic Review



The prognosis, specifically the case fatality and duration, of untreated
tuberculosis is important as many patients are not correctly diagnosed and
therefore receive inadequate or no treatment. Furthermore, duration and case
fatality of tuberculosis are key parameters in interpreting epidemiological

Methodology and Principal Findings

To estimate the duration and case fatality of untreated pulmonary
tuberculosis in HIV negative patients we reviewed studies from the
pre-chemotherapy era. Untreated smear-positive tuberculosis among HIV
negative individuals has a 10-year case fatality variously reported between
53% and 86%, with a weighted mean of 70%. Ten-year case
fatality of culture-positive smear-negative tuberculosis was nowhere
reported directly but can be indirectly estimated to be approximately
20%. The duration of tuberculosis from onset to cure or death is
approximately 3 years and appears to be similar for smear-positive and
smear-negative tuberculosis.


Current models of untreated tuberculosis that assume a total duration of 2
years until self-cure or death underestimate the duration of disease by
about one year, but their case fatality estimates of 70% for
smear-positive and 20% for culture-positive smear-negative
tuberculosis appear to be satisfactory.


Publisher: Public Library of Science

Date Published: 4-April-2011

Author(s): Tiemersma E., van der Werf M., Borgdorff M., Williams B., Nagelkerke N.


Leave a Reply