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Etiology

Low blood pressure was not associated with increased mortality in very elderly persons after adjustment for poor health status

ACP J Club. 1999 Jan-Feb;130:20. doi:10.7326/ACPJC-1999-130-1-020


Source Citation

Boshuizen HC, Izaks GJ, van Buuren S, Ligthart GJ. Blood pressure and mortality in elderly people aged 85 and older: community based study. BMJ. 1998 Jun 15;316:1780-4.


Abstract

Question

In persons aged 85 years and older, is blood pressure associated with all-cause mortality after adjustment for poor health status?

Design

Community-based cohort study with 5- to 7-year follow-up (Leiden 85 Plus Study).

Setting

Leiden, the Netherlands.

Participants

830 adults aged 85 years and older (mean age 90 y, 74% women) who had blood pressure recorded at baseline (1986 to May 1989) and were living in Leiden.

Assessment of risk factors

A physician visited the participants in their homes at baseline and collected data on age, sex, parents' country of origin, marital status, medical history, medications, mental status (Mini-Mental State Examination), and function (activities of daily living). Common laboratory tests were also done. Blood pressure was measured once at the end of the interview and rounded up to the nearest 5 mm Hg. Diastolic blood pressure (DBP) was classified as 50 to 60, 65 to 70, 75 to 80 (relative risk [RR] set at 1.0), 85 to 90, 95 to 100, and > 100 mm Hg. Systolic blood pressure (SBP) was classified as 90 to 120, 125 to 140, 145 to 160 (RR set at 1.0), 165 to 180, 185 to 200, and > 200 mm Hg. Relatives and caregivers provided missing data as needed, and medical charts were used for some data on patients in nursing homes.

Main outcome measures

Patients were followed until 1 March 1994. Mortality data were taken from the municipal register and nursing home records. Data were stratified by age and sex and included adjustment for baseline variables.

Main results

During follow-up, 578 adults died. Crude 5-year all-cause mortality was 88% (95% CI 79% to 95%) for DBP 50 to 60 mm Hg and 59% (CI 44% to 72%) for DBP > 100 mm Hg; it was 85% (CI 78% to 91%) for SBP < 125 mm Hg and 59% (CI 38% to 78%) for SBP > 200 mm Hg. When mortality rates were adjusted for confounders, including sex; age; living independently; ability to eat, wash, or dress without help; Mini-Mental State Examination scores; serum albumin levels; heart disease, excluding hypertension; use of glycosides; and cancer, the association between low blood pressure and increased mortality disappeared.

Conclusion

The relation between low blood pressure and increased all-cause mortality in adults aged 85 years and older was associated with poor health status.

Sources of funding: Netherlands Prevention Fund; National Institutes of Health; Dutch Ministry of Health, Welfare, and Sports.

For correspondence: Dr. H.C. Boshuizen, TNO Prevention and Health, Division of Public Health and Prevention, Leiden, The Netherlands. FAX 31-71-518-1903.


Commentary

Although it is clearly worthwhile to treat hypertension in patients who are young-old (65 to 80 years of age), debate continues over the recommendations for patients older than 80 years of age, especially those who are frail. Recently, U-shaped and inverse mortality curves have been shown. Increased mortality among those with lower blood pressure suggests at least 2 possibilities: toxicity of treatment (from interference with autoregulation or other mechanisms) or confounding by comorbid conditions. The well-executed, mainly community-based Dutch study by Boshuizen and colleagues supports the latter possibility because poor health was more common in those with low blood pressure.

This epidemiologic study was not designed to address whether hypertension in patients older than 80 years of age should be treated. Furthermore, only mortality was studied. Equally important is whether treatment lowers the incidence of morbidity (such as strokes) and disability even without a positive effect on mortality. Only a proper randomized controlled trial can supply a clear answer.

The landmark study by Amery and colleagues (1) actually found a small yet disturbing increase of untoward events in the treatment group older than 80 years of age compared with control-patients. Another trial showed no benefit of treatment for those older than 80 years of age (2).

My own advice to clinicians with respect to treatment of hypertension in patients who are frail and older than 80 years of age is summed up by 2 adages well known to geriatricians. First, "treat it—but only if you can get away with it." Second, with respect to medication use, "start low, go slow, and sometimes say 'no'."

A. Mark Clarfield, MD
Herzog Memorial HospitalJerusalem, IsraelSir Mortimer B. Davis-Jewish General HospitalMontreal, Quebec, Canada


References

1. Amery A, Birkenhager W, Brixko R, et al. Efficacy of antihypertensive drug treatment according to age, sex, blood pressure and previous cardiovascular disease in patients over the age of 60. Lancet. 1986;2:589-92.

2. Dahlof B, Lindholm LH, Hansson L, et al. Morbidity and mortality in the Swedish Trial in Old Patients with Hypertension (STOP-Hypertension). Lancet. 1991;338: 1281-5.