101DELIRIUM IN ACUTE ILLNESS IS NOT ASSOCIATED WITH HYPOTENSION OR BLOOD PRESSURE VARIABILITY: A CONSECUTIVE COHORT STUDY IN PATIENTS WITH VASCULAR DISEASE

Abstract

Introduction: Perioperative hypotension and blood pressure variability have been linked to increased delirium risk. Blood pressure variability is also associated with cardiovascular risk, poor outcome after stroke, and possibly with risk of dementia. In the absence of previous data, we examined blood pressure characteristics in relation to delirium in a consecutive cohort of hospitalised patients with a history of vascular disease. Methods: The Oxford Vascular Study (OXVASC) is a longitudinal, population-based study of acute vascular events occurring with a defined population of 92,728 in Oxfordshire. All surviving OXVASC patients who had acute illness requiring assessment in secondary care over three separate periods between 2013 and 2015 were prospectively studied. Delirium was ascertained using a clerking proforma including the AMTS and Confusion Assessment Method (CAM). Blood pressure records for each case and an age and sex-matched control were manually digitised. Results: Forty-one cases of delirium (mean ± sd age = 81 ± 2 years) and an equal number of controls (mean ± sd = 80 ± 5 years) were identified. There were no significant differences between those with vs without delirium in any blood pressure variable including mean ± sd systolic blood pressure (SBP) on admission (148 ± 40 vs 140 ± 29 mmHg), diastolic blood pressure (DBP) on admission (76 ± 21 vs 69 ± 15 mmHg), maximum SBP (170 ± 30 vs 162 ± 23 mmHg), minimum SBP (108 ± 22 vs 105 ± 20 mmHg), SBP range (62 ± 26 vs 58 ± 20 mmHg), DBP range (42 ± 15 vs 37 ± 16 mmHg), SBP coefficient of variation (0.13 vs 0.13), and DBP coefficient of variation (0.16 vs 0.15). The number (%) of patients with any SBP ≥160 mmHg (23 (56%) vs 25 (61%)) or any SBP < 100 mmHg (14 (34%) vs 18 (44%)) was also similar. Conclusions: Hypotension and blood pressure variability were not associated with delirium in our cohort of older vascular patients with acute illness. Our preliminary findings suggest that blood pressure variability appears unlikely to play a major role in the pathogenesis of delirium.