Orthostatic hypotension in healthy elderly: Is it a myth?

BACKGROUND: Orthostatic hypotension (OH) is common among older people and is more prevalent in elderly with various disorders and on medications. AIMS: The objective of the study was to know the prevalence of orthostatic hypotension in healthy geriatric subjects. SUBJECTS AND METHODS: The study group comprised of healthy non hypertensive, non diabetic elderly individuals aged 60 years and above (n=80) and another group, healthy aged 30 to 50 years age (n=80, mean age39.2±5.3). Orthostatic hypotension was defined as a decline in systolic/diastolic blood pressure of ≥20/10 mmHg when an individual changed from a supine to a standing position within 3 minutes of standing. Systolic and Diastolic blood pressure was measured in supine position and within 3 minutes of standing.
RESULTS: 1 out of 80 (1.25%) in the elderly subjects was found to have orthostatic hypotension.
CONCLUSION: The study concluded that the orthostatic hypotension is less prevalent in healthy elderly subjects without any illness or without on any medications.

Introduction

Orthostatic hypotension (OH) is a common problem among elderly patients, associated with significant morbidity and mortality. While acute OH is usually secondary to medication, fluid or blood loss, or adrenal insufficiency, chronic orthostatic hypotension is frequently due to altered blood pressure regulatory mechanisms and autonomic dysfunction[1].

OH develops if the compensatory mechanisms fail to resist the approximately 500-mL reduction of blood coming to the heart as a person stands up from a lying position. When cardiac output decreases, baroreceptors located in the heart, aorta, and carotid artery are stimulated to increase the heart rate and cause peripheral vasoconstriction to maintain the blood pressure[2]. OH is a common clinical finding in older persons, with a prevalence of 6%[3] to 30%,[4].

There is an obvious need to measure orthostatic Blood Pressure of elderly persons, as low Blood Pressure and OH are important risk factors especially among the frail elderly persons. The aim of our study was to explore the prevalence of OH in healthy elderly individuals aged above 60 years of age.

Subjects and Methods

The study population included 80 healthy subjects above 60 years of age who attended the free camps for the aged and 80 healthy volunteers aged 30 to 50 years age. Orthostatic hypotension was defined as a decline of 20mm of Hg or more in systolic blood pressure or 10 mm of Hg or more in Diastolic blood pressure on assumption of upright posture within 3 to 5 minutes[5]. After obtaining verbal and written informed consent, the age, sex of the subjects and the medical history (which included history of diabetes and hypertension, history of smoking, alcoholism, family history of hypertension, any medications taken) was recorded. The elderly subjects having hypertension, Diabetes mellitus, any other debilitating illnesses, on medications, subjects unable to stand up were excluded from the study. The subjects in the age group 30 – 50 years were non diabetic, non hypertensive, non smokers, non alcoholic, not on any medications and not suffering from any diseases. All subjects in the study satisfied the inclusion and exclusion criteria. The study was approved by the Institutional Ethical Committee. There was no financial burden on the subjects.

Blood pressure was measured in the right upper limb with the subjects being in supine position for supine blood pressure. Blood pressure was measured by the same examiner using a standard mercury sphygmomanometer. The supine blood pressure recordings were made after 5 minutes of rest. After recording blood pressure in supine position first, the patient was asked to stand up quickly for 3 minutes and blood pressure was recorded again on immediate standing and after 3 minutes of standing.

Statistical study

The Statistical software namely SPSS 11.0 was used for the analysis of the data and Microsoft word and Excel have been used to generate tables. Data were expressed as mean ± SEM.

Results

Only 1 out of the 80 elderly healthy subjects had OH and OH was not observed in any individual who were aged between 30 to 50 years age (Table 1).

Table 1

Percentage distribution of orthostatic hypotension (OH) in different age groups.

The mean systolic and mean diastolic blood pressures were higher in older subjects when compared to the younger subjects. (Table 2 and 3).

Table 2

Mean Blood Pressure measurements in different Posture in subjects aged ≥60 years age.

Table 3

Mean Blood Pressure measurements in different Posture in subjects aged 30-50 years age.

Discussion

In this study the healthy elderly subjects aged above 60 years had a higher baseline systolic and diastolic Blood pressure when compared to the younger age group. As people age, large arteries gradually stiffen and small arteries may become partially blocked and this tends to increase the blood pressure. This could be the reason for the higher baseline blood pressure in the subjects aged 60 years and above.

The prevalence of OH in the healthy elderly in our study was 1.25%. Orthostatic Hypotension was less prevalent in the healthy elderly subjects. In normal elderly subjects, the prevalence of OH is reported to be between 5 and 30%[6]. Elderly subjects are often taking medications, such as antihypertensive and diuretics that can cause or aggravate OH. Neurological diseases such as diabetic neuropathy, Parkinson's disease, multiple system atrophy and the autonomic neuropathies further increase the likelihood of OH[6]. Orthostatic hypotension in the elderly may be due to age-related physiologic changes in blood pressure regulation, to certain disorders, or to use of certain drugs. Since the study subjects were neither suffering from any disorders nor taking any medications the prevalence of OH was less. In the group aged between 30- 50 years none showed OH. In a study done earlier, the prevalence of OH in middle aged segment of general population was close to 6%. The impaired orthostatic homeostasis was associated with age, female gender, low BMI, hypertension, antihypertensive treatment, diabetes and current smoking[7]. The healthy subjects were non diabetic, non hypertensive, non alcoholic and non smokers and their mean age was less. This might be the reason for not observing OH in any of the subjects in this group.

Conclusion

These results indicate that underlying disease process and the medications used for treatment is major causes for orthostatic hypotension in the elderly. Ageing in healthy individuals may not cause orthostatic hypotension. Further studies are required to confirm these findings especially using a large group of geriatric healthy subjects to represent the Indian population.