Type 2 Diabetes

Type 2 diabetes (T2D) is a chronic metabolic disorder characterized by progressive insulin resistance and relative insulin secretory deficiency, resulting in persistently elevated blood glucose. Over time, hyperglycemia damages blood vessels and nerves throughout the body, causing cardiovascular disease, chronic kidney disease, peripheral neuropathy, diabetic retinopathy, and lower-limb amputation. T2D is largely preventable: structured lifestyle interventions reduce progression from prediabetes to T2D by 58 percent, according to the landmark NIH Diabetes Prevention Program trial.

• Increased thirst and frequent urination
• Unexplained fatigue
• Blurred vision
• Slow-healing cuts or bruises
• Frequent infections (skin, bladder, gum)
• Tingling, numbness, or pain in hands and feet (neuropathy)
• Darkened skin in folds (acanthosis nigricans) — often first sign in younger adults
• Weight loss despite normal eating (less common in T2D than T1D)

Fasting plasma glucose (FPG ≥126 mg/dL), 2-hour oral glucose tolerance test (≥200 mg/dL), or A1C (≥6.5%) diagnoses diabetes; prediabetes is FPG 100–125 mg/dL or A1C 5.7–6.4%. The ADA 2024 Standards of Care recommend offering all prediabetic adults a structured lifestyle program (the National DPP) and considering metformin for those at highest risk. Retinal screening and annual foot exams should begin at diagnosis for all T2D patients.

The ADA 2024 Standards of Care recommend metformin as the preferred first-line agent when medication is indicated, with individualized A1C targets (less than 7% for most adults; less than 8% for older adults or those with limited life expectancy). For patients with established cardiovascular disease or high cardiovascular risk, an SGLT2 inhibitor (empagliflozin, dapagliflozin) or GLP-1 receptor agonist (semaglutide, liraglutide) is recommended as second-line therapy due to proven cardiovascular and kidney protection. SGLT2 inhibitors reduce CKD progression independent of glucose lowering. Diabetes self-management education through an ADA-recognized program, medical nutrition therapy, and continuous glucose monitoring (CGM) where accessible are central pillars of care. Emerging evidence supports structured low-carbohydrate dietary approaches for A1C reduction and, in some cases, diabetes remission.