Volume 23, Issue 11 pp. 1063-1073
Original Article

Metformin is associated with a lower risk of active tuberculosis in patients with type 2 diabetes

Shang-Yi Lin

Shang-Yi Lin

Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

School of Medicine, Graduate Institute of Medicine, Sepsis Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

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Hung-Pin Tu

Hung-Pin Tu

Department of Public Health and Environmental Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

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Po-Liang Lu

Po-Liang Lu

Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

School of Medicine, Graduate Institute of Medicine, Sepsis Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

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Tun-Chieh Chen

Tun-Chieh Chen

Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

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Wen-Hung Wang

Wen-Hung Wang

Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

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Inn-Wen Chong

Inn-Wen Chong

Department of Respiratory Therapy, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

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Yen-Hsu Chen

Corresponding Author

Yen-Hsu Chen

Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

School of Medicine, Graduate Institute of Medicine, Sepsis Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsin Chu, Taiwan

Correspondence: Yen-Hsu Chen, Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, 100 Tzyou 1st Road, Kaohsiung City, Taiwan. Email: [email protected]Search for more papers by this author
First published: 25 June 2018
Citations: 28
(Associate Editor: Cynthia Chee; Senior Editor: Paul King)
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ABSTRACT

Background and objective

Metformin is an oral anti-diabetic therapy (ADT) to manage type 2 diabetes mellitus (T2DM), and has been reported to have potential anti-tuberculosis (TB) effects. This study investigates the risk of active TB among persons with T2DM who were treated with various ADT and insulin therapies.

Methods

We conducted a nationwide population-based cohort study using the Taiwan Longitudinal Health Insurance Database, including 49 028 T2DM patients who were metformin users (n = 44 002) or non-users (n = 5026). A total of 5026 propensity score-matched pairs of metformin users and non-users with T2DM were evaluated from 1998 to 2010. The data were analysed using Cox proportional hazard models.

Results

Patients with T2DM had a significantly higher rate of incident TB than did the control subjects (adjusted hazard ratio: 2.01; 95% confidence interval (95% CI): 1.80–2.25). After adjusting for comorbidities, diabetes complications, ADT type and statin use, metformin use was an independent factor for predicting a reduced risk of active TB (adjusted relative risk (aRR): 0.24; 95% CI: 0.18–0.32). The association between metformin use and active TB risk was also consistent in most subgroup analyses, except for patients with metabolic disorders (aRR: 0.46; 95% CI: 0.11–1.87). This protective effect of metformin was dose-dependent but diminished gradually in the elderly population.

Conclusion

Among all types of ADT and insulin therapies, metformin is the only agent with a decreased risk of active TB in the T2DM population. However, this effect was diminished in the elderly population and was not observed in patients with metabolic disorders.

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