Orthostatic Blood Pressure Increases Risk of Death in Elderly
Orthostatic Blood Pressure Increases Risk of Death in Elderly
By Pat McGinley, FNP, MSNSummary—Orthostatic hypotension (OH) is a major risk factor for dizziness, which often results in falls, increased morbidity, and/or mortality in the elderly. A recently published study in the Archives of Internal Medicine examined the effects of OH and the resulting risk of death from vascular or nonvascular causes. The researchers defined OH as a drop of 20 mm/Hg or more in systolic blood pressure (BP) or a 10 mm or more drop in diastolic BP, either at one minute or three minutes after standing from a lying position. Diastolic OH at one minute and systolic OH at three minutes represented the greatest risk of vascular death in the elderly population. Clinicians need to screen elderly patients for the presence of orthostatic changes and use caution when prescribing volume-depleting and/or vasodilating medications.1
About 30% of the elderly have inadequate physiologic responses to position change due to atherosclerosis, hypovolemia, and/or medications used to treat hypertension and ischemic heart disease. Autonomic dysfunction secondary to systemic diseases such as diabetes, alcoholism, or Parkinson’s disease also may result in OH.2 BP is the product of heart rate, stroke volume, and total peripheral resistance.3 When changing from a lying to a standing position, about 500 fewer millimeters of blood are returned to the heart, which leads to a transient decrease in cardiac output and drop in BP.4
The normal physiologic response to decreased BP includes peripheral vasoconstriction and stimulation of baroreceptors in the heart, aorta, and carotid arteries to increase the heart rate. When this mechanism functions properly, a person can change positions rapidly without experiencing lightheadedness or near-syncope. When this mechanism fails, reduced organ perfusion occurs, resulting in OH. Systolic hypotension (OH-S) represents sympathetic failure that impairs peripheral vasoconstriction. Diastolic hypotension (OH-D) represents malfunction of baroreceptors or factors affecting cardiac filling. This inadequate response causes symptoms of lightheadedness, dizziness, and near fainting, thereby increasing the risk of falls, injury, and death in the elderly.
Concern about this phenomenon prompted researchers in Finland to conduct a four-year study to determine the risk of vascular vs. nonvascular death associated with OH.
Study Methodology
The study cohort consisted of 792 people age 70 or older, all of whom were living at home (vs. a skilled nursing facility or hospital environment) in one of five rural municipalities. The mean age of the group was 76; the mean body mass index (BMI = weight in kg divided by square of height in meters) was 28.4.
Other characteristics of the study group included the following:
• 38% were men;
• 22% self-rated their health as good; 57% as average; 21% as poor;
• 20% were diabetics;
• 1% had a previous stroke;
• 34% had a diagnosis of congestive heart failure;
• 21% had coronary heart disease;
• 31% had low cognition based on a Mini-Mental State Examination (MMSE);5
• 31% used psychotropic drugs;
• and 1% had Parkinson’s disease.
Study subjects were given questionnaires, interviewed, and given a physical examination as well as appropriate clinical tests during the study period. Examinations were performed on two separate days with an average interval of three months. The questionnaire included data about the following:
• symptoms of dizziness;
• dry mouth;
• straining chest pain;
• resting dyspnea;
• self-rating of personal health;
• current smoking habits;
• and functional assessment. (Could subject perform seven common activities of daily living unassisted?)
Researchers established the following definitions for OH:
• OH-S1: ³ 20 mm drop of systolic BP measured at one minute;
• OH-S3: ³ 20 mm drop of systolic BP measured at three minutes;
• OH-D1: ³ 10 mm drop of diastolic BP measured at one minute;
• and OH-D3: ³ 10 mm drop of diastolic BP measured at three minutes.
A registered nurse performed an MMSE and measured BP in the right arm using a mercury sphygmomanometer. Each subject rested for five minutes prior to the first BP measurement. Blood pressures and pulse rates then were measured at one minute and three minutes after changing from a lying to a standing position. Pulse rates were recorded 30 seconds after resting and 2.5 minutes after standing up.
A physician reviewed past medical records, looking for documentation of chronic medical conditions and recorded current medication use. In addition, the physician performed a physical examination that included vibratory sensation assessment and determination of BMI. A physiotherapist assessed health-related factors not addressed by the registered nurse and performed muscle strength, peak flow rates, and balance measures when patients self-reported symptoms of dizziness when turning their necks.
Final data analysis included review of official death certificates indicating the times and main cause of death in the study subjects from the initiation of the study until the end of the four-year follow-up period.
Table 1. Risk of Developing VDT Associated with Travel |
| • recent surgery |
| • recent period of prolonged bed rest |
| • current pregnancy |
| • recent venous trauma |
| • current administration of contraceptive pill or steroids |
| • known cancer |
| • known systemic disease |
| • known coagulopathy |
| Source: Ferrari E, Chevallier T, Chapelier A, Baudouy M. Travel as a risk factor for venous thromboembolic disease. Chest 1999;115:440-444. |
Much data was obtained and analyzed by the researchers. Approximately 30% (240) of the 792 screened study participants were found to have OH as defined by the study authors. Some participants experienced diastolic OH only and some systolic only, while some had both, resulting in researchers recording OH in 411 cases. Each type of OH was evaluated for statistical significance. Results showed the following:
• OH-S1: diagnosed in 22% (172) of subjects;
• OH-S3: diagnosed in 19% (148) of subjects;
• OH-D1: diagnosed in 6% (45) of subjects;
• and OH-D3: diagnosed in 6% (46) of subjects.
At the end of the four-year study period, investigators measured vascular and nonvascular death rates by reviewing death certificates. Interestingly, survival time before vascular and nonvascular death was not significantly different between those diagnosed with OH and those who were not.
However, among those with OH, the following findings were prognostic indicators: Significant OH associated with vascular mortality occurred with a drop in diastolic BP at one minute (OH-D1) as well as a drop in systolic BP at three minutes (OH-S3). Further analysis found a diastolic drop of 0-9 mm/Hg was most predictive of poor prognosis; greater than 9 mm/Hg drop was not statistically significant. A systolic drop of 20 mm/Hg or greater also predicted a poorer prognosis than a drop of less than 20 mm.
Vascular death was more likely to occur in subjects with the following characteristics:
• advanced age (> 80 years);
• a diagnosis of diabetes, congestive heart failure or stroke;
• low cognitive status (based on MMSE);
• high systolic blood pressure;
• use of four or more medications;
• low peak expiratory flow;
• rest dyspnea at least every other day;
• and absent sense of vibration.
Diastolic OH at one minute was associated with the diagnosis of diabetes, CHF, stroke, hypertension, a low BMI, as well as symptoms of dizziness, dry mouth, and dizziness when turning the neck. OH-D1 occurred more commonly in subjects using calcium channel blockers, diuretics, and psychotropic drugs.
Systolic OH occurring at three minutes was associated with a diagnosis of hypertension, diabetes, high systolic and diastolic BP, and low BMI. The only significant gender difference occurred in men with higher systolic and diastolic blood pressures than in study subjects without OH. Women who had OH tended to have higher systolic BP and lower BMI than women who did not have OH.
Clinical Implications
The elderly (age 65 years and older) represent 13% of the U.S. population yet account for 38% of our health care dollars.6 Caring for the elderly, preserving quality of life as well as quantity, presents a challenge for the clinician. A thorough history and physical examination is imperative when caring for any patient. However, the elderly must be screened for the presence of OH to reduce the risk of vascular deaths or other morbidity.
Important elements of the patient history and physical examination include the following:
• use of prescribed and over-the-counter medications, especially volume-depleting or vasodilating agents;
• symptoms of dizziness when standing or when turning the neck;
• amount of liquids consumed on a daily basis;
• and blood pressure and pulse rate recorded initially with the patient lying down, then after standing at one and three minutes.
Patient education for those experiencing OH cannot be stressed enough. Caution the elderly patient to linger a few minutes at the bedside before rising from a lying position. The patient must understand the importance of adequate hydration to prevent OH even though he may be taking a diuretic agent.
Researchers conclude that control of existing hypertension, especially isolated systolic hypertension, is the best single factor to reduce the incidence of OH. Controlling this common medical condition and careful screening for OH will help the elderly continue to enjoy longer lives without disability.
References
1. Luukinen H, Koski K, Laippala P, et al. Prognosis of diastolic and systolic orthostatic hypotension in older persons. Arch Int Med 1999;159:273-280.
2. Carlson M, Thames M. Approach to the patient with syncope. In: Kelly WM, ed. Textbook of Internal Medicine. 3rd ed. Philadelphia: Lippincott-Raven; 1997:343.
3. Leier C. Approach to the patient with hypotension and shock. In: Kelly WM, ed. Textbook of Internal Medicine. 3rd ed. Philadelphia: Lippincott-Raven; 1997:361.
4. Lipstiz LA. Orthostatic hypotension in the elderly. N Engl J Med 1989;321:952-957.
5. Folstein M, Molstein S, McHugh P. "Mini-Mental State." A practical method for grading the cognitive state of patients for the clinician. J Psych Res 1975;12:189.
6. Pawlson L, Parrott M. Epidemiology of aging and its implications for health, health care, and social policy. In: Kelly WM, ed. Textbook of Internal Medicine. 3rd ed. Philadelphia: Lippincott-Raven;1997:120.
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