Diabetes mellitus significantly increases the risk of developing active tuberculosis (TB) and worsens TB treatment outcomes. Chronic hyperglycemia impairs innate and adaptive immune responses, particularly macrophage and T-cell function, facilitating reactivation of latent infection and severe disease progression.

Diabetes mellitus (DM) is increasingly recognized among people living with HIV (PLHIV). The relationship is bidirectional: HIV infection causes chronic inflammation and immune activation, increasing insulin resistance. Antiretroviral therapy (ART), particularly protease inhibitors, contributes to metabolic complications. Diabetes worsens cardiovascular risk, renal disease, and infection outcomes in PLHIV.

Hypoglycaemia is defined as a blood glucose level below 3.9 mmol/L and is one of the most common acute complications of diabetes treatment. It occurs when blood glucose falls below the level required to meet the body's metabolic demands, usually because of excess insulin or glucose-lowering medication relative to carbohydrate intake or energy expenditure.

Hyperglycaemia in pregnancy refers to elevated blood glucose levels occurring during pregnancy and includes both gestational diabetes mellitus (GDM) and pre-existing diabetes (type 1 or type 2 diabetes diagnosed before or during pregnancy). Gestational diabetes mellitus is defined as any degree of glucose intolerance first recognized during pregnancy that does not meet the diagnostic criteria for overt diabetes.

Religious fasting is commonly practiced in many faith traditions. People with diabetes may choose to fast, but fasting alters normal meal timing and metabolic balance, increasing the risk of hypoglycaemia, hyperglycaemia, dehydration, and ketoacidosis.