1.6 Epidemiological indicators

When a National TB Programme (NTP) functions well, indicators can be obtained from the local authorities and NTP.
The WHO tuberculosis country profiles also provide an estimation of TB indicators by individual country1 .

Box 1.1 - Most common indicators

Annual incidence rate of TB cases(a)
Numerator: number of new TB cases (all forms) that occur in a population over one year
Denominator: population at the start of the year

Annual incidence rate of smear-positive PTB cases(a)
Numerator: number of new smear-positive PTB cases that occur in a population over one year
Denominator: population at the start of the year

Prevalence of smear-positive PTB cases over a given period of time, usually one year(b)
Numerator: number of smear-positive PTB cases
Denominator: population at the start of the period of time

Proportion of multidrug- and rifampicin-resistant TB cases among TB cases over a given period of time(c)
Numerator: number of multidrug- and rifampicin-resistant TB cases
Denominators:
- Total number of TB cases
- Number of new TB cases
- Number of previously treated TB cases 

Proportion of extensively drug-resistant TB cases among TB cases over a given period of time(c)
Numerator: number of extensively drug-resistant cases
Denominators: as for multidrug- and rifampicin-resistant TB cases

Proportion of HIV-infected patients among new TB cases over a given period of time(c)
Numerator: number of HIV-infected patients
Denominator: number of new TB cases

(a) The rate is expressed as the number of new TB cases (or new smear-positive PTB cases) per 100,000 population.
(b) Prevalence is expressed as the number of smear-positive PTB cases per 100,000 population. It includes new and pre-existing cases. Prevalence represents approximately double the incidence rate.
(c) Proportion is expressed in %.



Footnotes
Ref Notes
1 For more information: https://worldhealthorg.shinyapps.io/tb_profiles/?_inputs_&lan=%22EN%22&entity_type=%22group%22&group_code=%22AFR%22