The Duration of the Orthostatic Blood Pressure Drop is Predictive of Death

Background : Orthostatic hypotension (OH) affects 6% of community-dwelling older people. This increases to 60% when non-invasive, continuous blood pressure (BP) monitoring is used, due to identification of transient drops in BP which recover rapidly. Aim : To determine the clinical relevance of these transient orthostatic BP drops. Design : Five-year clinical observational study. Methods : One hundred three consecutive new patients attending a Falls and Syncope Clinic in the UK from 1 February 2009 underwent continuous BP monitoring during an active stand. BP profiles were analysed to quantify all reductions in BP, measuring the duration of any drop below diagnostic criteria. Five-year follow-up data were extracted from hospital clinical records to assess clinical outcomes. Results : Systolic BP (sBP) dropped ≥20 mmHg in 76 (74%) individuals, with 65 (63%) having ≥10 mmHg drop in diastolic BP. However, only 22 (21%) cases were diagnosed clinically with OH. A sustained reduction in BP (≥30 s) had a sensitivity of 0.91 and specificity of 0.88 for a clinical diagnosis of OH, being more accurate than absolute BP reduction alone. A sustained reduction in sBP was associated with greater use of vasopressors (36%, P 0.001) and an independent, significantly greater risk of death (45% at 5 years, P 0.009). Conclusion : An orthostatic reduction in sBP lasting ≥30 s improves accuracy of diagnosis. Moreover, given the significant adverse outcomes with a sustained reduction, clinicians should consider this when diagnosing and treating patients, as transient OH does not appear to be clinically significant.