Undetected burden of tuberculosis in a low-prevalence area

Int J Tuberc Lung Dis. 2006 Apr;10(4):415-21.


Setting: Under-ascertainment and under-reporting of tuberculosis (TB) hampers surveillance and control. Case detection is improved by record linkage of case registers and under-reporting can be estimated by capture-recapture (CR) analysis.

Objectives: To assess the completeness of the TB registration systems and estimation of TB incidence and under-reporting in the Piedmont Region of Italy in 2001.

Methods: Record linkage of the 'physician notification system', the TB laboratory register and the hospital records register, and subsequent three-sample CR analysis.

Results: Record linkage identified 657 TB cases; CR analysis estimated 47 (95%CI 31-71) unrecorded cases. Under-reporting of the 'physician notification system' was estimated at 21% (95%CI 20-23). The overall estimated TB incidence rate was 16.7 cases per 100000 population (95%CI 16.3-17.3), varying according to the subset investigated: 12.7 for individuals from low TB prevalence countries and 214.1 for immigrants from high TB prevalence countries; 13.1 and 25.8 for persons aged < and > or = 60 years, respectively; and 32.1 in Turin, the regional capital and 10.8 in the rest of the region.

Conclusions: When multiple recording systems are available, record linkage and CR analysis can be used to assess TB incidence and the completeness of different registers, contributing to a more accurate surveillance of local TB epidemiology.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Diagnosis, Differential
  • Female
  • Humans
  • Incidence
  • Infant
  • Italy / epidemiology
  • Male
  • Mass Screening / methods*
  • Middle Aged
  • Population Surveillance*
  • Prevalence
  • Retrospective Studies
  • Risk Factors
  • Tuberculosis / diagnosis*
  • Tuberculosis / epidemiology*