What are the diagnostic criteria for orthostatic hypotension in older adults?

Orthostatic Hypotension Diagnostic Criteria

Orthostatic hypotension is diagnosed when there is a sustained decrease in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg within 3 minutes of standing, or when systolic blood pressure drops to <90 mmHg. 1

Standard Diagnostic Thresholds

The diagnostic criteria are straightforward and universally accepted across major guidelines:

• Systolic BP drop ≥20 mmHg within 3 minutes of standing 1
• Diastolic BP drop ≥10 mmHg within 3 minutes of standing 1
• Absolute systolic BP <90 mmHg within 3 minutes of standing 1, 2

Modified Criteria for Hypertensive Patients

In patients with baseline supine hypertension, use a higher threshold of systolic BP drop ≥30 mmHg to diagnose orthostatic hypotension. 1, 2 This adjustment accounts for the fact that hypertensive patients can tolerate larger absolute drops while maintaining adequate perfusion pressure.

Proper Measurement Technique

The accuracy of diagnosis depends entirely on correct measurement technique:

Patient Preparation

• Have the patient rest supine or sitting for 5 minutes before the initial measurement 1, 2
• Patient should fast for 3 hours before testing 1, 2
• Avoid caffeine, nicotine, and stimulant-containing beverages on the day of testing 2
• Perform testing in a temperature-controlled environment (21-23°C) 2

Measurement Protocol

• Measure baseline BP in both arms at the first visit; if the difference is >10 mmHg, use the arm with higher readings for all subsequent measurements 1, 2
• Use a validated and calibrated device with appropriate cuff size 1, 2
• Measure BP at 1 minute and 3 minutes after standing 1, 2
• Maintain the arm at heart level during all measurements 2
• Record heart rate simultaneously to distinguish neurogenic from non-neurogenic causes 2

Continuous beat-to-beat BP monitoring devices are superior to intermittent cuff measurements for accurate diagnosis, as interval devices have low concordance with continuous measurements. 2 Standard automated oscillometric devices may miss rapid BP changes and should be supplemented with manual auscultatory measurements when initial testing is equivocal. 1

Subtypes Based on Timing

Classic Orthostatic Hypotension

• BP drop meeting criteria within 3 minutes of standing 1
• Most common presentation 1

Initial (Immediate) Orthostatic Hypotension

• Transient BP decrease >40 mmHg systolic and/or >20 mmHg diastolic within 15 seconds of standing 1, 2
• Often associated with presyncope or syncope 1
• Requires continuous BP monitoring to detect 2

Delayed Orthostatic Hypotension

• BP drop meeting criteria but occurring beyond 3 minutes of standing 1, 2
• Pattern of BP decrease is more variable than classic OH 2
• Extend standing time beyond 3 minutes if symptoms suggest OH but initial testing is negative 2

Distinguishing Neurogenic from Non-Neurogenic OH

The heart rate response differentiates the underlying mechanism:

• Neurogenic OH: Blunted heart rate increase (<10 bpm) due to impaired autonomic control 2, 3
• Non-neurogenic OH: Preserved or enhanced heart rate increase (typically >15 bpm) as seen with volume depletion 3, 4

This distinction is critical because it guides treatment strategy and identifies patients with autonomic failure who require specialized management. 2, 5

Common Pitfalls to Avoid

• Do not diagnose OH based on symptoms alone—many patients are asymptomatic despite meeting BP criteria 6
• Do not use seated-to-standing measurements as equivalent to supine-to-standing—seated measurements produce smaller depressor responses due to reduced gravitational stress 6
• Do not rely on single measurements—reproducibility should be confirmed, especially when initiating treatment 7
• Do not overlook medication review—drugs are the most frequent reversible cause of OH 3, 5, 8

Clinical Context in Older Adults

Orthostatic hypotension is present in approximately 10% of community-dwelling older adults and up to 50% of institutionalized elderly patients. 2 The prevalence increases to 20% in adults over 65 years and reaches 33% in elderly hospital inpatients. 3 Age-related physiological changes—including stiffer hearts less responsive to preload, impaired vasoconstrictor reflexes, baroreflex dysfunction, and reduced cerebral autoregulation—predispose older adults to OH even without specific disease processes. 3

Symptoms in older adults depend more on the absolute BP level reached than on the magnitude of the fall, so a patient with baseline hypertension may tolerate larger drops asymptomatically. 2 Conversely, frail elderly patients may become symptomatic with smaller drops that don't meet standard criteria, warranting clinical judgment in borderline cases. 9