1.6 Epidemiological indicators

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    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 country a Citation a. For more information:
    https://worldhealthorg.shinyapps.io/tb_profiles/?_inputs_&entity_type=%22group%22&lan=%22FR%22
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    Box 1.1 – Most common indicators

     

    Annual incidence rate of TB cases (a) Citation a. The rate is expressed as the number of new TB cases (or new smear-positive PTB cases) per 100,000 population.
    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) Citation a. The rate is expressed as the number of new TB cases (or new smear-positive PTB cases) per 100,000 population.
    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) Citation 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.
    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) Citation c. Proportion is expressed in %.
    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) Citation c. Proportion is expressed in %.
    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) Citation c. Proportion is expressed in %.
    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 %.