1.4 Prognosis

Without treatment, TB is a severe and potentially fatal disease. After 5 years without treatment, the outcome of smear-positive pulmonary TB (PTB) in non-HIV-infected patients is as follows1:

  • 50 to 60% die (case fatality ratio (CFR) for untreated TB);
  • 20 to 25% are cured (spontaneous cure);
  • 20 to 25% continue to have symptoms.

In non-HIV infected patients, the CFR is estimated at 3%2. Untreated TB in HIV-infected patients (not on effective antiretroviral therapy) is almost always fatal. Even on antiretroviral therapy, the CFR is higher than in non-HIV infected patients3,4.

Risk factors for poor outcomes of TB treatment (death and relapse) include co-morbidities (e.g. HIV infection, diabetes, COPD), cavities on chest x-ray, high bacillary load and resistance to TB drugs.



References

  1. Tiemersma EW, van der Werf MJ, Borgdorff MW, Williams BG, Nagelkerke NJ. Natural history of tuberculosis: duration and fatality of untreated pulmonary tuberculosis in HIV negative patients: a systematic review. PLoS One. 2011;6(4):e17601. Published 2011 Apr 4.
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3070694/pdf/pone.0017601.pdf

  2. Straetemans M, Glaziou P, Bierrenbach AL, Sismanidis C, van der Werf MJ (2011) Assessing Tuberculosis Case Fatality Ratio: A Meta-Analysis. PLoS ONE 6(6): e20755.
    https://doi.org/10.1371/journal.pone.0020755
    https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020755

  3. World Health Organization. Global Tuberculosis Report 2021. Geneva: World Health Organization; 2021.
    https://apps.who.int/iris/rest/bitstreams/1379788/retrieve

  4. Manosuthi, W., et al. Survival rate and risk factors of mortality among HIV/tuberculosis-coinfected patients with and without antiretroviral therapy. J Acquir Immune Defic Syndr, 2006. 43(1): p. 42-6.
    https://journals.lww.com/jaids/fulltext/2006/09000/Survival_Rate_and_Risk_Factors_of_Mortality_Among.7.aspx