More than 7 years ago, Spanish scientists found that taking blood pressure medication at bedtime instead of in the morning could reduce the risk of heart attack, stroke and death by 61%.
This means it would extend people’s life expectancy by 5.5 years.
The next best thing for lowering heart attack and stroke risk is cholesterol-lowering medication, and that’s only a 35% reduction.
However, the study went unnoticed. One reason is that “extraordinary claims require extraordinary evidence to be believed”.
Now in a recent study, researchers in Western Canada will finally answer the question: when is the best time to take blood pressure medication?
Their study is called BedMed, and it has already recruited 947 patients (and counting) with the help of 155 family physicians.
It is not only investigating the purported health benefits, but also the risks.
There is the possibility of huge benefits from changing the time you take your blood pressure medicine, but there could also be unrecognized harms no one has looked at before.
Why timing may matter
For the one in five Canadians with high blood pressure, medication is often prescribed for daytime use.
This is based on the assumption that the medication will combat the increase in blood pressure that may happen while the person is active.
The normal pattern is for blood pressure to be higher during the day and lower at night.
So why might taking blood pressure medication at night, when blood pressure is already lower, reduce the risk of a heart attack?
It is known that if you don’t dip lower at night, you have a higher risk of having a heart attack or stroke.
Taking the medication at night preferentially lowers bedtime blood pressure and creates a more normal rhythm. If the benefit to bedtime prescribing is real, that may be why.
The BedMed aims to show whether there truly is a benefit for everyone. Their goal is to recruit 8,750 participants from Alberta, British Columbia and Manitoba.
In addition to investigating whether taking blood pressure medication at night time reduces the risk of heart attacks, strokes and death, BedMed will attempt to find three potential harms.
One is visual changes.
It has been shown that if you have glaucoma, and if you also have lower than normal blood pressure while you sleep, your vision deteriorates more quickly.
The second is falls and fractures.
There is a legitimate concern that older adults who get up in the middle of the night may experience dizziness—due to lower than usual blood pressure—and fall and cause a fracture.
The third is dementia.
This concern is pure speculation. Lowering overnight blood pressure could be helpful or harmful so far as developing dementia.
The relationship between blood pressure and dementia is highly complex.
The participation entails sending out a letter to suitable patients informing them of BedMed and managing any resulting medication changes.
The study is also unique because it has been co-developed and co-managed with a 10-member patient working group.
Scott Garrison, an associate professor in the University of Alberta, leads the study.
Source: University of Alberta.