04/11/2025
Resistant hypertension in a diabetic patient
Resistant hypertension is defined as blood pressure that remains above target despite the use of three antihypertensive medications at optimal doses, including a diuretic, or when four or more drugs are needed to control it.
🧠 Key Criteria
Confirmed diagnosis:
Office BP ≥140/90 mmHg (or ≥130/80 mmHg in diabetics) despite ≥3 drugs, one of which is a diuretic.
OR controlled BP but requiring ≥4 medications.
True vs. pseudo-resistance:
Rule out poor adherence, incorrect BP measurement, white coat effect, and suboptimal drug dosing.
🔍 Why it matters
Resistant hypertension is a red flag for:
Secondary causes (e.g., primary aldosteronism, renal artery stenosis, obstructive sleep apnea, pheochromocytoma).
End-organ damage (e.g., LVH, CKD, retinopathy).
Increased cardiovascular risk (stroke, MI, heart failure).
It requires a structured evaluation to rule out secondary causes, optimize therapy, and assess end-organ damage. Labs should target renal, endocrine, and cardiovascular systems. Management includes lifestyle, pharmacologic intensification, and specialist referral.
🧪 Stepwise Evaluation: Labs and Diagnostics
Confirm true resistance:
Ensure adherence, correct BP measurement, and exclude white coat effect (ambulatory BP monitoring).
Basic labs:
Electrolytes, BUN, creatinine: assess renal function.
eGFR and urine albumin-to-creatinine ratio: screen for diabetic nephropathy.
HbA1c, fasting glucose: glycemic control.
Lipid panel: cardiovascular risk.
Secondary hypertension workup:
Renin and aldosterone levels: screen for primary aldosteronism (especially if hypokalemia).
TSH: rule out hypothyroidism.
24-hour urinary metanephrines or plasma free metanephrines: pheochromocytoma.
Sleep study: if clinical suspicion of obstructive sleep apnea.
Renal artery Doppler or CTA/MRA: if renal artery stenosis suspected.
Cardiac evaluation:
ECG: LVH or ischemia.
Echocardiogram: LV function, hypertrophy, diastolic dysfunction.
💊 Pharmacologic Management
Triple therapy must include a diuretic:
Thiazide-like diuretics (chlorthalidone or indapamide) preferred over hydrochlorothiazide.
If eGFR