Diabetes and Metabolic Disorders
Core concepts
Diagnose diabetes by A1c ≥6.5%, fasting glucose ≥126, 2-hour OGTT ≥200, or random ≥200 with symptoms; prediabetes is A1c 5.7–6.4% or fasting 100–125. Screen adults 35–70 with overweight/obesity, and screen earlier with risk factors.
Modern pharmacotherapy is comorbidity-driven, not just A1c-driven. In ASCVD, heart failure, or CKD, choose a GLP-1 receptor agonist or SGLT2 inhibitor with proven benefit regardless of A1c. Obesity is a strong indication for GLP-1 agents. Metformin remains a reasonable first agent for many, but it is not mandatory before a cardiorenal-protective drug. Know SGLT2 inhibitor cautions (genital mycotic infections, euglycemic DKA, volume depletion) and GLP-1 cautions (GI effects, pancreatitis, medullary thyroid cancer history).
Goals: A1c <7% for most; relax to <8% in limited life expectancy, severe comorbidity, or high hypoglycemia risk. Annual monitoring: urine albumin-to-creatinine ratio, eGFR, dilated eye exam, comprehensive foot exam; statin therapy and BP control are core.
Traps
- Metformin and eGFR - reduce dose at eGFR 30–45, stop below 30; hold around iodinated contrast if AKI risk.
- Sulfonylureas/insulin cause hypoglycemia - the wrong choice when the stem emphasizes avoiding lows.
- SGLT2 inhibitors are not for type 1 and can cause euglycemic DKA.
- Don't forget hypoglycemia in older adults and the need to deintensify.
Rule of thumb
Read the comorbidity first: ASCVD or obesity → GLP-1; HF or CKD → SGLT2 inhibitor. If the stem stresses hypoglycemia avoidance or cost, favor metformin, SGLT2, or GLP-1 over sulfonylurea/insulin.