FNP endocrinology: diabetes management, thyroid disease, and metabolic syndrome

A1C targets (ADA 2024): Most adults with type 2 diabetes: <7%. Less stringent target (<8%) appropriate for limited life expectancy, advanced complications, extensive comorbidities, or high hypoglycaemia risk. More stringent (<6.5%) appropriate for select patients without hypoglycaemia risk (e.g., short duration, managed with lifestyle ± metformin).

Medication selection framework — beyond glucose lowering:

• ASCVD established or high risk → GLP-1 RA (liraglutide, semaglutide) or SGLT2 inhibitor with cardiovascular benefit
• Heart failure or CKD → SGLT2 inhibitor (renal and cardiovascular protective; empagliflozin, dapagliflozin, canagliflozin)
• Obesity — weight loss priority → GLP-1 RA (greatest weight loss); SGLT2 inhibitor (moderate)
• Hypoglycaemia avoidance priority → DPP-4 inhibitors, GLP-1 RA, SGLT2 inhibitors (neutral to low risk)
• Cost sensitivity → Metformin, sulfonylureas, NPH insulin (lowest cost)

Metformin considerations: First-line when tolerated. Contraindicated if eGFR <30 (hold at <45 for most), IV contrast (hold 48h pre/post for eGFR 30–60), active hepatic disease, heart failure with haemodynamic instability, excessive alcohol use. B12 deficiency with long-term use — check annually.

GLP-1 receptor agonists: Semaglutide (oral Rybelsus and injectable Ozempic) and tirzepatide (dual GLP-1/GIP — Mounjaro/Zepbound) represent the most potent weight loss and A1C reduction options. Contraindicated in personal/family history of medullary thyroid carcinoma or MEN type 2. GI side effects (nausea, vomiting) are common — mitigated by slow dose titration.

Hypothyroidism: TSH is the best screening and monitoring test. TSH >4–5 mIU/L with low free T4 = overt hypothyroidism. Levothyroxine is first-line — dose approximately 1.6 mcg/kg/day. Check TSH 6–8 weeks after initiation or dose change. Take on empty stomach, 30–60 minutes before food. Separate from calcium, iron, and PPI by ≥4 hours. Target TSH: 0.5–2.5 mIU/L (most adults); 0.1–2.5 in pregnancy (trimester-specific).

Hyperthyroidism: TSH suppressed (<0.1) + elevated free T4/T3. Graves disease (most common) = diffuse goitre + ophthalmopathy + dermopathy. Management options: antithyroid drugs (methimazole — first choice; PTU in pregnancy first trimester), radioactive iodine ablation, or thyroidectomy. Beta-blockers for symptom control (propranolol or atenolol). Thyroid storm = emergency: PTU (blocks new hormone synthesis AND peripheral T4→T3 conversion), iodine (after PTU), corticosteroids, beta-blockers.

Thyroid nodules: Evaluate with TSH. If suppressed → radionuclide scan (hot nodule = hyperfunctioning, low cancer risk; cold nodule = higher risk). If TSH normal/elevated → ultrasound. Biopsy (FNA) for nodules with suspicious features (solid, hypoechoic, irregular margins, microcalcifications, increased vascularity). Size alone does not determine biopsy need.

Metabolic syndrome diagnosis (ATP III criteria, any 3 of 5): Waist circumference (>102 cm men, >88 cm women), TG ≥150 mg/dL, HDL <40 (men)/<50 (women) mg/dL, BP ≥130/85 mmHg, fasting glucose ≥100 mg/dL (including treated diabetes).

Management: Lifestyle intervention is the primary treatment — 7–10% weight loss improves all five components. Address each component with specific treatment. Assess 10-year ASCVD risk with pooled cohort equations. Statin therapy for elevated LDL. Intensive lifestyle program (structured diet + exercise) or pharmacotherapy (orlistat, GLP-1 RA, SGLT2i) for weight loss.

Prediabetes: IFG (100–125 mg/dL fasting) or IGT (2-hour glucose 140–199 mg/dL post-OGTT) or A1C 5.7–6.4%. Refer to structured diabetes prevention program. Metformin if BMI ≥35 or previous GDM or age <60. Annual diabetes screening.