| Test | Diabetes | Prediabetes | Normal |
|---|---|---|---|
| Fasting Plasma Glucose | ≥126 mg/dL | 100-125 mg/dL | <100 mg/dL |
| 2-hr OGTT (75g) | ≥200 mg/dL | 140-199 mg/dL | <140 mg/dL |
| HbA1c | ≥6.5% | 5.7-6.4% | <5.7% |
| Random Glucose + symptoms | ≥200 mg/dL | - | - |
Confirm with repeat test on different day unless symptomatic hyperglycemia
| Feature | Type 1 | Type 2 |
|---|---|---|
| Pathophysiology | Autoimmune beta-cell destruction | Insulin resistance + secretion defect |
| Body habitus | Usually lean | Often overweight/obese |
| Ketosis prone | Yes - DKA | HHS more common |
| C-peptide | Low/absent | Normal or high |
| Autoantibodies | GAD65, IA-2, ZnT8 | Absent |
| Treatment | Insulin always required | Lifestyle, oral agents, insulin |
| Parameter | Target |
|---|---|
| HbA1c (general) | <7% |
| HbA1c (older/frail) | <8% |
| HbA1c (pregnancy) | <6% |
| Fasting glucose | 80-130 mg/dL |
| Post-meal (2hr) | <180 mg/dL |
| BP target | <130/80 mmHg |
| LDL | <100 (<70 if ASCVD) |
| Drug Class | Key Agents | Key Benefit | Watch For |
|---|---|---|---|
| 1st line - Metformin | Metformin | Weight neutral, inexpensive, CV benefit | Hold if eGFR <30; GI side effects |
| ASCVD / HF / CKD - add: | GLP-1 RA or SGLT-2i | CV and renal protection | GLP-1: nausea; SGLT-2: UTI, DKA |
| GLP-1 Agonists | Semaglutide, Liraglutide, Dulaglutide | Weight loss, CV events reduction | Nausea, pancreatitis, MTC (contraindicated) |
| SGLT-2 Inhibitors | Empagliflozin, Dapagliflozin | Reduce HF hospitalization, CKD progression | Genital mycosis, euglycemic DKA |
| DPP-4 Inhibitors | Sitagliptin, Linagliptin | Weight neutral, low hypoglycemia risk | Saxagliptin: increased HF hospitalization |
| Sulfonylureas | Glipizide, Glimepiride | Inexpensive, effective | Hypoglycemia, weight gain |
| Insulin | Basal glargine/detemir, Basal-bolus | Most potent glucose lowering | Hypoglycemia, weight gain |