Introduction
Type 2 diabetes (T2D) results from insulin resistance with progressive β-cell failure. Treatment aims to prevent microvascular (retinopathy, nephropathy, neuropathy) and macrovascular (MI, stroke) complications, with the drug chosen by the patient's cardiovascular and kidney risk as well as glucose.
Targets
- HbA1c < 7% (53 mmol/mol) for most; tighter (6.5%) in young patients without hypoglycaemia risk; looser (7.5–8%) in the elderly, frail or with hypoglycaemia.
- BP < 130/80, LDL according to risk (statin for most patients), stop smoking.
Lifestyle
Weight loss (≥ 5–10%, remission possible with ≥ 15%), diet, at least 150 minutes of exercise a week. This is the base of all treatment.
Strategy (ADA/EASD)
- Metformin plus lifestyle for most patients at diagnosis.
- Established cardiovascular disease, high CV risk, heart failure or CKD: add an SGLT2 inhibitor and/or GLP-1 receptor agonist with proven benefit, regardless of HbA1c.
- Obesity: prefer GLP-1 receptor agonists (or tirzepatide).
- If HbA1c is above target, add another drug every 3 months; cost may favour sulfonylureas.
- Very high glucose (HbA1c > 10%) or symptoms of catabolism: start insulin.
Metformin first; for patients with heart disease, heart failure or kidney disease add an SGLT2 inhibitor or GLP-1 agonist whatever the HbA1c, because they protect the heart and kidneys.