CLINIC, BUT NOT 24-HOUR, BLOOD-PRESSURE IS RELATED TO ORTHOSTATIC HYPOTENSION IN ELDERLY UNTREATED HYPERTENSIVE PATIENTS

Background: This was a prospective study of consecutive subjects seen in the hypertension clinic at Leicester General Hospital to investigat e the prevalence of and the factors predicting orthostatic hypotension in untreated elderly hypertensive subjects. Methods: We studied 106 c onsecutive untreated, though otherwise unselected, hypertensive subjec ts with systolic blood pressure (SBP) of 160 mm Hg or higher and/or di astolic blood pressure (DBP) of 90 mm Hg or higher who were either new ly diagnosed or withdrawn from antihypertensive therapy for over 1 mon th before the study. Mean age of the subjects was 75.4 years (range, 6 4 to 86 years). Clinic blood pressure readings were recorded with the patients in a supine position and after 1 and 3 minutes standing. Subj ects also underwent 24-hour noninvasive ambulatory blood pressure moni toring, assessment of their 24-hour urinary electrolyte excretion, and assessment for the presence of left ventricular hypertrophy. Results: Systolic orthostatic hypotension, defined as a drop in SBP of 20 mm H g or more within 3 minutes of standing from a supine position, was fou nd in 27.4% of subjects. Subjects with orthostatic hypotension had hig her levels of supine clinic SBP (187 mm Hg vs 173 mm Hg, P = 0.01), al though no significant difference in supine clinic DBP or orthostatic c hange in pulse rate was found. No significant differences in mean 24-h our blood pressure levels, day-to-night change, or mean hourly SBP wer e found between those with and without orthostatic hypotension. Supine clinic SBP and the presence or absence of symptoms were the only fact ors found to be of predictive value on logistic regression analysis. C onclusions: Orthostatic hypotension is common in untreated elderly hyp ertensive subjects. Elevated supine SBP is related to the presence of orthostatic hypotension. Orthostatic hypotension is unrelated to 24-ho ur ambulatory blood pressure levels or diurnal blood pressure change.