At what age should secondary hypertension be suspected in patients?

Age Thresholds for Suspecting Secondary Hypertension

Comprehensive screening for secondary hypertension is recommended in adults diagnosed with hypertension before age 40 years, with the exception of obese young adults where obstructive sleep apnea evaluation should be prioritized first. 1

Primary Age-Based Screening Criteria

Young Adults (Age <40 years)

• Onset before age 30 years is a key clinical clue warranting thorough evaluation for secondary causes 2, 3
• The 2024 ESC Guidelines specifically recommend comprehensive screening for main causes of secondary hypertension in adults diagnosed before age 40 years 1
• For patients ≤30 years with elevated brachial blood pressure, measure thigh blood pressure and consider coarctation of the aorta if lower than arm pressures 3
• Important caveat: Primary hypertension can manifest at younger ages, particularly in Black patients, so age alone is not definitive 3

Older Adults (Age >50-60 years)

• New-onset hypertension after age 50 years may suggest renovascular hypertension caused by atherosclerosis 4
• Atherosclerotic renovascular disease typically affects older adults (>60 years), while fibromuscular dysplasia affects younger women (<40 years) 3

Clinical Context Beyond Age That Mandates Evaluation

Age should not be considered in isolation—specific clinical presentations warrant secondary hypertension workup regardless of age:

High-Risk Presentations Requiring Investigation

• Resistant hypertension (BP >140/90 mmHg despite optimal doses of ≥3 drugs including a diuretic) 2, 3
• Severe or accelerated/malignant hypertension with grade III-IV retinopathy 2, 4
• Abrupt onset or sudden worsening of previously controlled hypertension 2, 3
• Target organ damage disproportionate to duration or severity of hypertension 2, 3
• Hypertensive urgency or emergency 2

Laboratory Red Flags

• Unprovoked hypokalemia suggesting primary aldosteronism 2, 3
• Serum creatinine increase ≥50% within one week of starting ACE inhibitor or ARB therapy 5

Physical Examination Findings

• Abdominal diastolic bruits suggesting renovascular hypertension 4
• Decreased femoral pulses suggesting coarctation of the aorta 4
• Features of Cushing syndrome (truncal obesity, purple striae) 2, 4
• Unilateral smaller kidney or kidney size difference >1.5 cm 5

Age-Specific Cause Considerations

Children and Adolescents

• Most common causes are renal parenchymal disease and coarctation of the aorta 5
• Hypertension before puberty strongly suggests secondary causes 5

Adults 65 Years and Older

• Common causes include atherosclerotic renal artery stenosis, renal failure, and hypothyroidism 5

Middle-Aged Adults

• Primary aldosteronism affects 8-20% of resistant hypertension cases and can occur at any age 3
• Obstructive sleep apnea is present in 25-50% of resistant hypertension cases 2

Common Pitfalls to Avoid

• Do not perform expensive imaging studies before completing basic laboratory screening 2
• Do not fail to consider medication-induced hypertension (NSAIDs, oral contraceptives, decongestants, stimulants) before extensive workup 2
• Do not delay evaluation in young patients because secondary causes are found in 20-40% of patients with malignant hypertension 6
• Recognize that delayed diagnosis can lead to irreversible vascular remodeling, affecting renal function and resulting in residual hypertension even after treating the underlying cause 7