Abstract P191: Orthostatic Hypotension and Blood Pressure Symptoms in the AASK Cohort Study

Abstract

Background: Orthostatic hypotension (OH) is defined using a consensus-based definition, namely, a drop in systolic blood pressure (SBP) ≥20 mmHg or diastolic BP (DBP) ≥10 mmHg or an increase in heart rate (HR) ≥20 bpm. Whether or not these definitions correspond with patient symptoms is unknown. Hypothesis: Traditional metrics for defining OH are arbitrary and warrant revision. Methods: SBP, DBP, and HR were assessed after 5 min in the rested, seated position and after 1 min of standing in black participants at each visit of the AASK cohort study (2002-2007; n=677). Postural change was determined by subtracting the seated SBP, DBP, or HR from the standing SBP, DBP, or HR. During each visit, participants were asked whether they experienced 26 distinct BP-related symptoms since last visit (yes or no). Relationships between SBP, DBP, and HR and symptoms were modeled via generalized estimating equations. Results: Participants were 40% women; mean age was 60 yrs (SD, 10) and mean number of follow-up visits was 19 (10). Mean (SD) resting SBP, DBP, and HR at baseline were 136 mmHg (22), 81 mmHg (13), and 69 bpm (12). After adjustment for age and sex, dizziness was the only symptom associated with all components of OH: SBP per -10 mmHg (OR 1.13; 95% CI 1.03, 1.23), DBP per -10 mmHg (1.12; 1.00, 1.26), and HR per 10 bpm (1.14; 1.03, 1.26). Light-headedness was associated with SBP (1.12; 1.03, 1.21) and HR (1.14; 1.05, 1.24), but non-significantly with DBP (1.11; 0.99, 1.23). When plotted continuously, there was no clear demarcation of risk between symptoms and conventional cut points. Rather, reduction in standing SBP and DBP were each associated with a higher proportion of symptoms at about -5 mm Hg, while increase in standing HR was associated with a higher proportion of symptoms as low as 5 bpm ( Figure ). Conclusions: Dizziness and light-headedness are symptoms most strongly associated with OH. The proportion with symptoms is greater at cut points less extreme than the consensus definition, demonstrating that the consensus definition of OH lacks sensitivity.