Continuous noninvasive orthostatic blood pressure measurements and their relationship with orthostatic intolerance, falls, and frailty in older people.

Objectives: To identify morphological orthostatic blood pressure (BP) phenotypes in older people and assess their correlation with orthostatic intolerance (OI), falls, and frailty and to compare the discriminatory performance of a morphological classification with two established orthostatic hypotension (OH) definitions: consensus (COH) and initial (IOH).

Design: Cross-sectional.

Setting: Geriatric research clinic.

Participants: Four hundred forty-two participants (mean age 72, 72% female) without dementia or risk factors for autonomic neuropathy.

Measurements: Active lying-to-standing test monitored using a continuous noninvasive BP monitor. For the morphological classification, four orthostatic systolic BP variables were extracted (delta (baseline - nadir) and maximum percentage of baseline recovered by 30 seconds and 1 and 2 minutes) using the 5-second averages method and entered in K-means cluster analysis (three clusters). Main outcomes were OI, falls (≥1 in past 6 months), and frailty (modified Fried criteria).

Results: The morphological clusters were small drop, fast overrecovery (n=112); medium drop, slow recovery (n=238); and large drop, nonrecovery (n=92). Their characterization revealed an increasing OI gradient (17.9%, 27.5%, and 44.6% respectively, P<.001) but no significant gradients in falls or frailty. The COH definition failed to reveal clinical differences between COH+ (n=416) and COH- (n=26) participants. The IOH definition resulted in a clinically meaningful separation between IOH+ (n=85) and IOH- (n=357) subgroups, as assessed according to OI (100% vs 11.5%, P<.001), falls (24.7% vs 10.4%, P<.001), and frailty (14.1% vs 5.4%, P=.005).

Conclusion: It is recommended that the IOH definition be applied when taking continuous noninvasive orthostatic BP measurements in older people.