Treating High Blood Pressure in the Elderly
If you're around my age (early 50s), then you are probably old enough to remember the days when standard advice for blood pressure treatment was based on age.
In the 1970s, for instance, the rule for blood pressure treatment was "120 plus age." A 50-year old, for instance, would have been advised that a blood pressure of 165 (less than the 170 cut-off) would have been just fine. For an 80-year old, the advised cut-off would have been 200! Looking back, it seems crazy that we could have accepted blood pressures like that, since it has since become clear that high blood pressure of that magnitude leads to significant increased risk of heart attack, stroke, kidney disease, even dementia.
Thankfully, such advice has fallen by the wayside, along with 8-track tapes and tie-dyed t-shirts.
But uncertainty - and perhaps reluctance - persists on the part of both the public and physicians to treat high blood pressure in the very elderly, particularly those in their late 70s and 80s. This has become especially true as target blood pressures in national guidelines for blood pressure treatment have ratcheted lower and lower. While current (JNC VII) recommendations for blood pressure recommend a level no higher than 140/90, emerging studies are suggesting that lower and lower levels are desirable. The NHANES experience in thousands of people, for instance, suggests that risk for cardiovascular events like stroke and heart attack begins to increase at a systolic blood pressure of 115--yes, 115! This raises some very difficult questions, as well as practical treatment issues, for blood pressure.
And it's not an uncommon question: The Framingham Study, the long-term observation of the residents of Framingham, Massachusetts, begun in 1948, has shown that 90% of people eventually develop hypertension as we age.
High blood pressure is therefore exceptionally common in the elderly. Up until recently, existing clinical data had questioned whether blood pressure reduction in the group provided genuine benefit. A large pooled analysis ("meta-analysis") of blood pressure treatment in the elderly, in fact, suggested that for every stroke or other cardiovascular event prevented by reducing blood pressure, it was offset by increased likelihood of death in other people. While such meta-analyses can only suggest an effect - not prove it - it dampened enthusiasm for vigorously treating blood pressure in elderly people.
However, the results of the HYVET trial have just been released and tell a different story. HYVET followed the more confident trial design of comparing people treated with a standard regimen, compared to a placebo group. Participants were "blinded" to treatment (i.e., they were unaware of what pill(s) they were provided). This sort of study design generally yields better information than meta-analyses.
The study was conducted by Dr. Nigel Beckett from the Imperial College London, along with colleagues from 195 centers in 13 countries, enrolling a total of 1933 participants taking one or more drugs to reduce blood pressure, 1912 taking placebo. The average age of participants was 83.6 years, starting blood pressure a clearly hypertensive 173/91. Participants receiving blood pressure treatment received the drug indapamide (a diuretic), with perindopril (an ACE inhibitor drug) added if necessary, with target blood pressure of 150/80. (The study was funded by the British Heart Foundation and the Institut de Recherches Internationales Servier, an organization affiliated with the drug industry.)
After nearly two years, differences became apparent: The group receiving treatment experienced:
- 34% less stroke
- 72% less congestive heart failure
- 27% less death from cardiovascular causes
- 28% less death from any cause
There were 138 total cardiovascular events in the group taking medication; 193 in the placebo group, translating into a 34% reduction.
The HYVET Trial therefore suggests that blood pressure treatment can indeed be undertaken in the elderly with substantial potential benefits not offset by adverse effects on non-cardiovascular health.
Next question: If HYVET suggests that people in older age ranges obtain benefit from reducing blood pressure to 150/80, will there be additional benefit by reducing it further, much as it does in younger age groups? As helpful as HYVET is in understanding hypertension in older people, it does not settle this issue. We'll have to wait for more research to settle that question.