Although the majority of patients with a diagnosis of TB have a good outcome because effective treatments are available, without treatment the mortality rate for tuberculosis is more than 50%. (1)
The following make a worse prognosis more likely:
- TB in the elderly, infants and young children.
 - people with TB who experience a delay in receiving treatment.
 - if there is radiological evidence of extensive spread.
 - people with severe respiratory compromise requiring mechanical ventilation. 
 - immunosuppression. 
 - multidrug resistant (MDR) tuberculosis. (1)
 
In addition:
- in the UK the mortality is 5%
 - mortality is highest in the socially disadvantaged
 - proper chemotherapy provides a cure in almost all immunocompetent patients
 - relapse rate is 1-2%; the rate is highest amongst poor compliers
 
Notes:
In 2021, the majority of people with extensively drug-resistant TB in England were born outside the UK, predominantly coming from Nigeria, Lithuania, Pakistan, India, and Romania (2)
Multidrug-resistant TB has a poorer prognosis than fully drug-susceptible TB, and risk factors include: (3) 
- Previous TB drug treatment (especially if there is a history of poor adherence or treatment failure).
 - Contact with a known index case of multidrug-resistant TB.
 - Country of origin with a high proportion of multidrug-resistant new TB cases.
 
There may be an increased risk of poorer outcomes among pregnant women and new mothers with TB (4)
 
Reference:
- 1. Tobin E. Tuberculosis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan
 - 2. UKHSA (2023) Tuberculosis in England, 2022 report (data up to end of 2021). UK Health Security Agency
 - 3. NICE (2019) Tuberculosis. National Institute for Health and Care Excellence
 - 4. UKHSA (2019) Pregnancy and tuberculosis (TB) Information for clinicians. UK Health Security Agency