REPRODUCIBILITY OF ORTHOSTATIC HYPOTENSION IN SYMPTOMATIC ELDERLY

PURPOSE: Variations in the reported prevalence of orthostatic hypotens ion (4% to 33%) are attributed to population selection and varied crit eria used to define orthostatic hypotension. Variation in the reproduc ibility of hemodynamic responses to orthostasis could be a further con founding variable. The purpose of this study was to evaluate reproduci bility of orthostatic blood pressure changes in patients with document ed symptomatic orthostatic hypotension. PATIENTS AND METHODS: Forty ou tpatients (mean age 77 +/- 8 years; 24 women) were recruited after ini tial presentation to a morning outpatient clinic with postural symptom s of dizziness (92%), falls (67.5%), or syncope (30%). Patients had a symptomatic drop in orthostatic systolic blood pressure of >20 mm Hg d ocumented in clinic. Subsequent cardiovascular assessment included aut onomic function tests, carotid sinus massage (supine and erect), and p rolonged head-up tilt tests. Blood pressure and heart rate measurement s were repeated during standing and head-up tilt on two further attend ances in the morning. RESULTS: A total of 67.5% patients had a drop in systolic blood pressure of >20 mm Hg on both visits during orthostati c stimuli; in the remainder, the response was not reproducible, and 5% had no significant orthostatic drop at either attendance. In 19 patie nts autonomic function tests were abnormal; orthostatic hypotension wa s reproducible in 79% of this group. In patients with normal autonomic function tests, 57% had reproducible orthostatic hypotension, of whic h only 60% were reproducible in those patients when further assessed i n the afternoon. CONCLUSIONS: Orthostatic blood pressure responses may not be reproducible in patients with documented symptomatic orthostat ic hypotension, particularly if autonomic function is normal and measu rements are taken in the afternoon. Repeated systolic blood pressure m easurements in the morning may be necessary to make a diagnosis in old er patients with suspected orthostatic hypotension.