What are the diagnostic criteria for orthostatic hypotension?

Orthostatic Hypotension Diagnostic Criteria

Orthostatic hypotension is diagnosed when systolic blood pressure drops ≥20 mmHg or diastolic blood pressure drops ≥10 mmHg within 3 minutes of standing from a supine or sitting position. 1

Standard Diagnostic Thresholds

The core diagnostic criteria are consistent across major guidelines:

• Systolic BP decrease ≥20 mmHg OR diastolic BP decrease ≥10 mmHg within 3 minutes of standing 1, 2, 3
• Alternatively, a sustained decrease in systolic BP to an absolute value <90 mmHg within 3 minutes also confirms the diagnosis 1, 2, 3
• For patients with supine hypertension, use a higher threshold: systolic BP drop ≥30 mmHg 1, 2

Subtypes Based on Timing

Orthostatic hypotension has distinct temporal patterns that affect diagnosis:

Initial (Immediate) Orthostatic Hypotension

• BP decrease >40 mmHg systolic and/or >20 mmHg diastolic within 15 seconds of standing 1, 2, 3
• BP spontaneously and rapidly returns to normal, with symptoms lasting <40 seconds 1, 3
• Often causes presyncope or syncope despite brief duration 1

Classic Orthostatic Hypotension

• Sustained reduction meeting standard criteria (≥20/10 mmHg) within 3 minutes of standing 1, 2, 3
• This is the most commonly recognized form in clinical practice 2

Delayed Orthostatic Hypotension

• BP drop meeting standard criteria but occurring beyond 3 minutes of standing 1, 2, 3
• Characterized by slow, progressive decrease in BP until reaching threshold 1, 3
• Requires extended standing time for detection if initial 3-minute testing is negative 2

Proper Measurement Technique

Critical measurement details that affect diagnostic accuracy:

Patient Preparation

• Patient should rest supine or sitting for 5 minutes before baseline measurement 2, 3
• Fast for 3 hours before testing 2
• Avoid nicotine, caffeine, theine, or taurine-containing drinks on the day of examination 2
• Testing should occur in temperature-controlled environment (21-23°C) 2

Measurement Protocol

• Use a validated and calibrated BP device with appropriate cuff size based on arm circumference 2
• Measure BP in both arms at initial visit; if systolic BP differs by >10 mmHg, use the arm with higher BP for all subsequent measurements 2
• Maintain arm at heart level during all measurements 2
• Take measurements at 1 minute and 3 minutes after standing 2, 3, 4
• For suspected delayed OH, extend standing time beyond 3 minutes if initial testing is negative but symptoms suggest OH 2

Important Diagnostic Considerations

Measurement Device Selection

• Continuous BP measurement devices are strongly preferred over interval devices for accurate diagnosis 2, 5
• Interval BP devices have low concordance with continuous measurements (positive agreement only 59.5%, negative agreement 72.5%) 5
• The prevalence of OH detected can differ significantly between device types, though not always statistically significant 5

Neurogenic vs. Non-Neurogenic OH

The heart rate response helps distinguish the underlying mechanism:

• Neurogenic OH: Orthostatic heart rate increase is blunted (usually <10 bpm) due to impaired autonomic control 2
• Non-neurogenic OH (e.g., hypovolemia): Orthostatic heart rate increase is preserved or enhanced 2

Clinical Pitfalls to Avoid

• Symptoms depend more on absolute BP level than magnitude of fall 2
• OH can be asymptomatic, particularly in older adults with chronic autonomic dysfunction 6, 4
• Pseudohypertension in elderly patients with calcified arteries may lead to overtreatment and iatrogenic OH 2
• Standard bedside testing may miss initial or delayed OH if timing is not extended appropriately 2

Prevalence and Clinical Context

• OH occurs in approximately 10% of all hypertensive adults and up to 50% of older institutionalized adults 2
• Prevalence is 20% in community-dwelling older adults and 5% in middle-aged adults 4
• OH accounts for 20-30% of syncope cases in older adults 7
• Associated with 64% increase in age-adjusted mortality and significantly increased cardiovascular risk 7, 4