Abstract Body: Background Hypertension management among very old adults is challenging due to a high prevalence of orthostatic hypotension (OH). However, the association between different classes of antihypertensive medications and temporal changes in blood pressure (BP) after standing has not been thoroughly characterized.

Objective To determine the association between antihypertensive medications and temporal changes in orthostatic BP among very old adults.

Methods Participants of the Atherosclerosis Risk in Communities (ARIC) Study underwent three supine and six standing BP measurements in 2023 (visit 10). Supine BPs were performed after 5 minutes of rest with a 30-second interval, and standing BPs were timed at 0, 1, 2, 3, 4, and 5 minutes after standing. We defined OH as a drop in BP of systolic ≥20 or diastolic ≥10 mm Hg after moving from the supine to standing position. Patterns of OH (initial, early, late, and sustained) were based on different combinations of 6 standing measurements over 6 minutes (see Figure 1 legend for definitions). We extracted antihypertensive medication data from ARIC using the Medispan generic product identifier and determined their associations with OH patterns via multivariable logistic regression (see Figure 2 for the medication list and Figure 3 legend for adjusted factors).

Results Of 941 participants (mean age 83.7±3.6 years, 60% female, 16% Black), 32% used beta blockers and 41% had initial OH (Figures 1 and 2). Beta blockers, alpha-beta blockers, and alpha blockers were associated with most of the types of OH. However, participants taking loop diuretics and vasodilators had higher odds of initial OH, while participants on thiazide diuretics had higher odds of late and sustained OH (Figure 3). Number of antihypertensive medications was not associated with any type of OH.

Conclusion Specific classes of antihypertensives, but not number of antihypertensive medications, were associated with OH. Future work should examine the short- and long-term effects of initiating treatment on orthostatic BP regulation and its sequelae over time.