Orthostatic hypotension at different times after standing erect in elderly adults.

Abstract

To the Editor: Orthostatic hypotension (OH) is an important cause of morbidity and mortality in the elderly adults. The prevalence varies widely (5–33%).1, 2 One of the factors responsible for these discrepancies is the variation in the definition of OH.3, 4 Despite the importance and easy detection of OH, there is controversy in the literature regarding the time at which blood pressure (BP) should be measured after standing.5 The measurement is commonly taken 3 minutes after position change. Few studies have performed a comparative analysis of BP in the several minutes after standing. The aim of this study was to identify the prevalence of OH, regardless of its cause, at four points after standing in elderly adults in an outpatient setting. Individuals followed up at the outpatient clinics of the Geriatric Medical Centre, University Hospital of Brasília, were consecutively and nonprobabilistically enrolled during 1 year. Inclusion criteria were aged 60 and older, undergoing outpatient treatment at the Geriatric Medical Centre, and providing informed consent. Exclusion criteria were inability to stand. After 5 minutes of rest, BP was measured in the supine position and 1, 3, 5, and 10 minutes after standing. BP was measured in the left arm using a mercury sphygmomanometer according to standards of the American Heart Association Council on High Blood Pressure.6 A drop in systolic blood pressure (SBP) of 20 mmHg or greater or of diastolic blood pressure (DBP) of 10 mmHg or greater, regardless of the time it occurred, was considered to indicate OH. One hundred eighty-one individuals, aged 60 to 96, were eligible for the study; 89 (49%) had OH at one or more times of measurement, 52 (58%) within 3 minutes and 37 (42%) after 3 minutes. There is a wide variation of data on the prevalence of OH, but there is a consensus that it increases with age.3-5 Different studies use different definitions of OH, which also contributes to the apparent variation in the prevalence of this condition. In addition, the same definition of OH is used in different ways in different studies. The time between measurements also varies. Some studies considered average blood pressure measured at different times. In others, a decrease only in SBP or only in DBP was considered for diagnosis.7 The definition most widely used for OH is based on the consensus of the American Autonomic Society and the American Academy of Neurology, published in 1996,8 but many individuals have symptoms of orthostatic intolerance with onset after 3 minutes from the variation of the position. Only a few studies have investigated OH since then.9, 10 Of the 89 individuals with OH in the study, 37 (42%) had a decrease in SBP or DBP only after 3 minutes. If the definition previously described had been considered, the prevalence of OH in this population would be 29%, as opposed to 49%. Measuring BP at different times after standing, before and after 3 minutes, increased the frequency of OH in this population (Table 1). Of the 30 participants who had OH in the first minute, 27 also had OH in the third minute. Only three patients had OH only in the first minute. Of the 37 patients with OH after the third minute, 18 (20%) had a decrease in BP evidenced in the fifth minute and 19 (21%) only in the tenth minute. The mean age of participants who had OH up to the third minute was 76.5, and that of participants who had OH after the first 3 minutes was 73.4 (P = .02). There is evidence that, if BP is measured for only up to 3 minutes, approximately half of the people would not be diagnosed with OH, which is a clinical condition associated with several other adverse conditions. The current recommendations for diagnosing OH in older adults in a tertiary-care hospital are inadequate. Further longitudinal and multicenter studies should be conducted to evaluate the best time to measure BP in the standing position and the clinical relevance of late OH. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: ACRC: acquisition of subjects and data, analysis and interpretation of data, preparation of manuscript. NAA, ALR, DFV: analysis and interpretation of data. MPF: analysis and interpretation of data, review of manuscript. MAVT: study concept and design, analysis and interpretation of data, preparation and review of manuscript. Sponsor's Role: The study had no external funding sources or conflicts of interest.