TB is a severe and often deadly disease without treatment. After 5 years without treatment, the outcome of smear-positive pulmonary TB (PTB) in HIV-negative patients is as follows:
– 50-60% die (case fatality ratio for untreated TB);
– 20-25% are cured (spontaneous cure);
– 20-25% develop chronic smear-positive TB.
With adequate treatment, the case fatality ratio (CFR) often falls to less than 2 to 3% under optimal conditions.
Similar CFRs are seen with untreated EPTB and smear-negative PTB, with an equivalent fall in CFR with adequate treatment.