The Complex Relationship Between Tuberculosis and Hyperglycemia

Hyperglycemia and tuberculosis are dual global pandemics. Each has a propulsive and amplifying effect on the other, and, because of this, we must consider hyperglycemia and tuberculosis together. Hyperglycemia is immunosuppressive and increases the risk of tuberculosis by threefold. It also leads to a more advanced presentation of pulmonary tuberculosis, thus increasing the likelihood of being smear positive and having cavitating lesions, and it impacts the duration and outcomes of treatment, with an increased one year mortality seen in patients with tuberculosis and diabetes. Additionally, any degree of hyperglycemia can have an impact on susceptibility to tuberculosis, and this effect is not limited to poorly controlled diabetes. Conversely, tuberculosis itself is associated with hyperglycemia and worsens hyperglycemia in those with diabetes mellitus. The impact of this relationship varies based on the base rates of each disease in different regions of the world. In order to successfully achieve the World Health Organization's goals of tuberculosis eradication and adequate glycemic control, we must improve our understanding, co-management, and screening of hyperglycemia and tuberculosis. This review aims to explore the current research investigating the relationship between tuberculosis and diabetes, including the changes in disease susceptibility, presentation, geographic distribution, and effects on treatment.