Risk of tuberculosis among people with diabetes mellitus: an Australian nationwide cohort study
- 1Department of Respiratory and Environmental Epidemiology, Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
- 2Department of Respiratory Medicine, Liverpool Hospital, Sydney, Australia
- 3Diabetes Centre, Bankstown-Lidcombe Hospital, Sydney, Australia
- Correspondence to Dr Claudia Caroline Dobler;
- Received 22 November 2011
- Accepted 20 January 2012
- Published 13 February 2012
Objective Previous studies that have found an increased risk for tuberculosis (TB) in people with diabetes mellitus (DM) have been conducted in segments of the population and have not adjusted for important potential confounders. We sought to determine the RR for TB in the presence of DM in a national population with data on confounding factors in order to inform the decision-making process about latent tuberculosis infection (LTBI) screening in people with diabetes.
Design Whole population historical cohort study.
Setting All Australian States and Territories with a mean TB incidence of 5.8/100 000.
Participants Cases of TB in people with DM were identified by record linkage using the National Diabetes Services Scheme Database and TB notification databases for the years 2001–2006.
Primary and secondary outcome measures Primary outcome was notified cases of TB. Secondary outcome was notified cases of culture-confirmed TB. RR of TB was estimated with adjustment for age, sex, TB incidence in country of birth and indigenous status.
Results There were 6276 cases of active TB among 19 855 283 people living in Australia between 2001 and 2006. There were 271 (188 culture positive) cases of TB among 802 087 members of the DM cohort and 130 cases of TB among 273 023 people using insulin. The crude RR of TB was 1.78 (95% CI 1.17 to 2.73) in all people with DM and 2.16 (95% CI 1.19 to 3.93) in people with DM using insulin. The adjusted RRs were 1.48 (95% CI 1.04 to 2.10) and 2.27 (95% CI 1.41 to 3.66), respectively.
Conclusions The presence of DM alone does not justify screening for LTBI. However, when combined with other risk factors for TB, the presence of DM may be sufficient to justify screening and treatment for LTBI.
To cite: Dobler CC, Flack JR, Marks GB. Risk of tuberculosis among people with diabetes mellitus: an Australian nationwide cohort study. BMJ Open 2012;2:e000666. doi:10.1136/bmjopen-2011-000666
Contributors All authors were involved in study concept and design, acquired data, revised the manuscript for important content and approved the final manuscript. CCD drafted the manuscript. GBM performed the statistical analysis.
Funding The study was funded by a grant from the Sydney South West Research Foundation. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
Competing interests None.
Patient consent The requirement for written or verbal patients consent for this data linkage study was waived by all of the above ethics committees because existing data sources were used.
Ethics approval The study protocol was approved by the Sydney South West Area Health Service Human Research Ethics Committee—Western Zone, the New South Wales Population & Health Services Research Ethics Committee, the Australian Institute of Health and Welfare Ethics Committee, the Queensland Health Research Ethics & Governance Unit, the Department of Human Services Victoria Research Governance, the Australian Capital Territory Health Human Research Ethics Committee, the Department of Health Western Australia Human Research Ethics Committee, the Tasmania Health and Medical Human Research Ethics Committee, the South Australia Department of Health Human Research Ethics Committee and the Northern Territory Human Research Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement There are no data available for sharing.
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