title: Quantifying errors in the estimation of tuberculosis mortality in a population of South African miners.
abstract: BACKGROUND
  All-cause mortality, based on national tuberculosis programme (NTP) register deaths, may under- or overestimate tuberculosis (TB) specific mortality in the population.
  
  
  OBJECTIVE
  To assess the factors influencing this measurement in a single large population with high TB prevalence and mortality.
  
  
  METHODS
  Routinely collected data on TB cases and treatment outcomes were linked to population data from a cohort of South African miners from 1995 to 2008. Vital status and cause of death were determined from multiple sources, including the TB programme, death register and autopsy.
  
  
  RESULTS
  The TB mortality rate, based on 430 deaths on the TB register, was 192/100,000 person-years (py). Many of these deaths (57%) were not caused by TB, and 483 TB deaths were identified outside the programme. Overall, there were 674 TB-specific deaths; the TB-specific mortality rate was 302/100,000 py. These deaths included 191 (28%) on the TB register, 23 (3%) among defaulters/transfers, 153 (23%) after anti-tuberculosis treatment and 307 (46%) in men who had never been on the programme.
  
  
  CONCLUSIONS
  This study highlights methodological issues in estimating TB mortality. In this population, a method using the product of TB incidence and case fatality consistently underestimated TB mortality. Accurate estimates of TB-specific mortality are crucial for the proper evaluation of TB control programmes.
authors.affiliation: Research Department of Infection and Population Health, University College London, London, UK. p.sonnenberg@ucl.ac.uk
authors.forename: P
authors.initials: P
authors.lastname: Sonnenberg
authors.forename: M S C
authors.initials: MS
authors.lastname: Lim
authors.forename: R J
authors.initials: RJ
authors.lastname: Dowdeswell
authors.forename: N
authors.initials: N
authors.lastname: Field
authors.forename: J R
authors.initials: JR
authors.lastname: Glynn
authors.forename: J
authors.initials: J
authors.lastname: Murray
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D004812:Epidemiologic Methods; D006801:Humans; D015994:Incidence; D008297:Male; D008906:Mining / Q000706:statistics & numerical data*; D009313:National Health Programs / Q000706:statistics & numerical data*; D015995:Prevalence; D012042:Registries; D012189:Retrospective Studies; D013019:South Africa / Q000453:epidemiology; D016896:Treatment Outcome; D014376:Tuberculosis / Q000188:drug therapy / Q000453:epidemiology / Q000401:mortality*
chemical_list: D000995:Antitubercular Agents