Abstract

BACKGROUND: Hypotensive episodes detected by 24-hour ambulatory blood pressure (BP) monitoring capture daily cumulative hypotensive stress and could be clinically relevant to cognitive impairment, but this relationship remains unclear. METHODS: We included participants from the Systolic Blood Pressure Intervention Trial (receiving intensive or standard BP treatment) who had 24-hour ambulatory BP monitoring measured near the 27-month visit and subsequent biannual cognitive assessments. We evaluated the associations of hypotensive episodes (defined as systolic BP drops of ≥20 mm Hg between 2 consecutive measurements that reached &lt;100 mm Hg) and hypotensive duration (cumulative time of systolic BP &lt;100 mm Hg) with subsequent cognitive function using adjusted linear mixed models. We further assessed 24-hour average BP and variability. RESULTS: Among 842 participants with treated hypertension (mean age, 71±9 years; 29% women), the presence (versus absence) of recurrent hypotensive episodes (11%) was associated with lower digit symbol coding scores (difference in <i>Z</i> scores, -0.249 [95% CI, -0.380 to -0.119]) and their faster declines (difference in <i>Z</i> score changes, -0.128 [95% CI, -0.231 to -0.026]). A consistent dose-response association was also observed for longer hypotensive duration with worse Montreal Cognitive Assessment and digit symbol coding scores. The association with digit symbol coding scores remained significant after further adjusting for 24-hour average BP and variability and was not observed for hypotension defined by clinic, orthostatic, or 24-hour average BP. Intensive BP treatment increased 24-hour hypotensive episodes and modified its association with the decline in digit symbol coding score. CONCLUSION: Twenty-four-hour hypotensive episodes were associated with worse cognitive function, especially in processing speed, and could be a novel marker for optimal BP control and dementia prevention.