Shang-Yi Lin1,2, Hung-Pin Tu3, Po-Liang Lu1,2,4, Tun-Chieh Chen1,5, Wen-Hung Wang1, Inn-Wen Chong6, Yen-Hsu Chen1,2,7. 1. Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. 2. School of Medicine, Graduate Institute of Medicine, Sepsis Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 3. Department of Public Health and Environmental Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 4. Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. 5. Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. 6. Department of Respiratory Therapy, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 7. Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsin Chu, Taiwan.
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.
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.