Cohort profile: AMBulatoRy blOod preSsure in older adults (AMBROSIA) and AMBROSIA-HOME

The AMBulatoRy blOod preSsure In older Adults (AMBROSIA) study cohort was designed to determine whether ambulatory blood pressure (BP) monitoring (ABPM) is useful for identifying older adults with hypertension taking antihypertensive medication who are at increased risk for falls. The association of home BP monitoring (HBPM) with falls was assessed in an ancillary study (AMBROSIA-HOME).

AMBROSIA was a prospective observational study of adults aged 65 years and older taking antihypertensive medication for hypertension. Participants were recruited from Kaiser Permanente Southern California (KPSC), an integrated healthcare delivery system, and enrolled from May 2019 to November 2022. Demographic and clinical characteristics and geriatric assessments were collected over the course of two consecutive study visits. Participants completed a 24-hour ABPM and 1 week of HBPM. Over the following year, falls were assessed using a monthly falls calendar, and serious fall injuries were assessed from the KPSC electronic health record (EHR).

We enrolled 670 participants; 656 completed 24-hour ABPM and 536 also completed HBPM. The mean (SD) age of the AMBROSIA cohort was 75 (6) years, 16% were over 80 years of age and 56% were female. There were 13% non-Hispanic Asian or Pacific Islander, 22% non-Hispanic Black, 18% Hispanic and 44% non-Hispanic White participants. Nearly 72% had mild cognitive impairment, 50% were pre-frail and 4% were frail. Overall, 87% of participants returned all monthly calendars during follow-up.

The AMBROSIA cohort can be updated with longitudinal data from the EHR including antihypertensive medication to explore the relationship of fall risk and white coat effect, defined as the difference between clinic BP and out-of-clinic BP, BP variability over 24 hours and postprandial BP decline with antihypertensive medication intensification during follow-up. Additionally, the cohort can be updated to include outcomes data from the EHR such as cardiovascular events to examine BP phenotypes as potential predictors of cardiovascular events.