Post-tuberculosis mortality risk among immigrants to British Columbia,Canada, 1985–2015: a time-dependent Cox regression analysis of linked immigration,public health,and vital statistics data

ObjectiveTo compare non-tuberculosis (non-TB)-cause mortality risk overall and cause-specific mortality risks within the immigrant population of British Columbia (BC) with and without TB diagnosis through time-dependent Cox regressions.MethodsAll people immigrating to BC during 1985–2015 (N = 1,030,873) were included with n = 2435 TB patients, and the remaining as non-TB controls. Outcomes were time-to-mortality for all non-TB causes, respiratory diseases, cardiovascular diseases, cancers, and injuries/poisonings, and were ascertained using ICD-coded vital statistics data. Cox regressions were used, with a time-varying exposure variable for TB diagnosis.ResultsThe non-TB-cause mortality hazard ratio (HR) was 4.01 (95% CI 3.57–4.51) with covariate-adjusted HR of 1.69 (95% CI 1.50–1.91). Cause-specific covariate-adjusted mortality risk was elevated for respiratory diseases (aHR = 2.96; 95% CI 2.18–4.00), cardiovascular diseases (aHR = 1.63; 95% CI 1.32–2.02), cancers (aHR = 1.40; 95% CI 1.13–1.75), and injuries/poisonings (aHR = 1.85; 95% CI 1.25–2.72).ConclusionsIn any given year, if an immigrant to BC was diagnosed with TB, their risk of non-TB mortality was 69% higher than if they were not diagnosed with TB. Healthcare providers should consider multiple potential threats to the long-term health of TB patients during and after TB treatment. TB guidelines in high-income settings should address TB survivor health.Electronic supplementary materialThe online version of this article (10.17269/s41997-020-00345-y) contains supplementary material, which is available to authorized users.