What is the prevalence of orthostatic hypotension in an Australasian emergency department population?

Objective: Orthostatic hypotension (OH) is associated with increased morbidity and there is limited research on the prevalence in the Australian ED population. The aim was to determine the prevalence of OH in an Australian ED population. Secondary outcomes included any associations of OH with symptoms, presenting complaints, patient demographics, or hospital admission, and the timing of OH findings.

Methods: Patients presenting to a regional Australasian ED underwent orthostatic measurements at 1, 3 and 5 min of standing following 5 min of supine bed rest. OH was defined as a drop in systolic and/or diastolic blood pressure by ≥20 and ≥10 mmHg, respectively.

Results: Of the 312 patients who were enrolled in the study, 69 (22.1%, 95% confidence interval 17.7-27.2%) had OH and 76.8% of cases were detected after 3 min of standing. There was evidence of difference in the prevalence of OH with age (P < 0.001). Similarly, there was evidence of a difference in supine systolic and diastolic blood pressure measurements (P = 0.012 and P < 0.001, respectively) between orthostatic and normotensive subjects. No association was found with OH and hospital admission, presenting complaints or comorbid medical illnesses.

Conclusions: In this single Australian ED population, there was a high prevalence of OH (22.1%) with most cases detected within 3 min of standing. A higher-powered study across multiple sites would better substantiate these findings.