Objective: Impact of SBP vs. DBP decrement during orthostasis on cardiovascular events in hypertension is not clear.
Methods: We assessed prospective association of orthostatic hypotension with mortality and major cardiovascular events [myocardial infarction (MI) and stroke] among 8788 treated hypertensive patients (52.2% men; mean age 52 years, mean BP 161/99 mmHg) without history of MI or stroke at baseline. Orthostatic hypotension was defined according to combined international consensus criteria, and as either systolic (decrease ≥20 mmHg) or diastolic orthostatic hypotension (decrease ≥10 mmHg). Final Cox regression model was adjusted for age, sex, supine SBP and DBP, diabetes, smoking, and total cholesterol.
Results: A total of 1060 (12.1%) study participants fulfilled combined orthostatic hypotension criteria, of these 886 (10.1%) met systolic and 290 (3.3%) diastolic criterion. In the crude analysis, combined orthostatic hypotension criteria were predictive of the composite endpoint, major cardiovascular event, total mortality, and stroke but not MI. After full adjustment, combined orthostatic hypotension criteria and systolic orthostatic hypotension were independently associated with stroke only (hazard ratio: 1.48, 1.07-2.05, P = 0.019, and 1.53, 1.08-2.15, P = 0.015, respectively), whereas the composite endpoint tended in the same direction (hazard ratio: 1.21, 0.98-1.51, P = 0.075, and 1.24, 0.99-1.55, P = 0.066, respectively). In contrast, diastolic orthostatic hypotension was associated with increased risk of MI (hazard ratio: 2.04, 1.20-3.46, P = 0.008).
Conclusion: Orthostatic hypotension has a dual role in cardiovascular events among hypertensive patients: SBP fall indicates higher risk of stroke, whereas DBP fall confers higher risk of MI.