Intra-individual postural blood pressure variability and stroke in elderlynursing home residents

Orthostatic hypotension (OH) is a potential risk factor for adverse cardiov ascular events, but OH is highly variable and may not be detected on a sing le occasion. To assess the relation between intra-individual variability of systolic orthostatic blood pressure change (Delta SBP) and cardiovascular outcomes, an algorithm was developed to identify Delta SBP instability usin g repeated supine and standing BP measurements. A cohort of 673 nursing hom e residents underwent baseline postural. BP measurements (supine to 1 minut e of standing, four times in a single day) and were followed for up to 2 ye ars. Two groups (stable vs. unstable) were identified based on an analysis of Delta SBP variance components. Differences in outcomes were compared via Cox survival analysis. At baseline 12.6% were unstable, defined as a one s tandard deviation difference of at least 20.2 mmHg between Delta SBP readin gs. Unstable subjects were more likely to have OH on at least one measureme nt (systolic BP drop of 20 mmHg or more; 85% vs. 36%, respectively) and to be on psychotropic medication at baseline (47% vs 35%) (P-values <0.001). O ther characteristics (including previous stroke) did not differ. During a m ean follow-up of 10.3 months, stroke incidence was higher in unstable subje cts (13.1% vs. 4.9%; P = 0.012), but ischemic heart disease and mortality r ates were not significantly different (respectively, 13.5% vs. 7.4%, P = 0. 115; 14.8% vs. 10.7%, P = 0.178). Survival analyses (adjusted far age, sex, psychotropic medications, body mass index, ischemic heart disease, and sup ine systolic pressure) confirmed a higher risk of stroke in unstable subjec ts (relative risk = 3.7, 95% CI: 1.6-8.4). Highly variable orthostatic BP m easures may reflect impaired BP regulatory mechanisms in elders with occult cerebrovascular disease, or may directly affect cerebral blood now. Orthos tatic BP Variability may be a better indicator of future stroke than a sing le supine or orthostatic change measure. (C) 2001 Elsevier Science Inc. All rights reserved.