New data from a major study called Sprint, released Monday, has shaken some of the basic assumptions about the treatment of high blood pressure. The trial found that lowering systolic blood pressure from currently recommended levels of 140 to 150 to below 120 could prevent heart attacks and strokes and potentially save many lives.
The study is remarkable and has many nuances. Here are three things that you should know about it.
First, the results should not be considered a mandate for people to run out and get treated so their blood pressures are below 120.
The Sprint trial included people 50 and older who had a systolic blood pressure — the higher number — between 130 and 180. Those under 75 needed to have evidence of heart disease, kidney disease or other risk factors. The study excluded people with diabetes or those who had experienced a stroke.
So the results apply only to a fraction of the people already being treated for high blood pressure and a smaller group of others. Over all, about one in 12 Americans would have been considered eligible for the study, or about 17 million adults. Of those already being treated for high blood pressure, one in six would have been eligible. What that also means is that five of six people already being treated for high blood pressure would not have fit into this study — making this evidence less relevant to them.
Another important aspect of the study was that the blood pressure was measured with patients sitting in a quiet area for five minutes, with no doctor present, using an automated machine that took three readings. With this approach blood pressure measurements tend to be lower than in rushed single measurements at the doctor's office.
If you are age 50 or older, with a top blood pressure number between 130 and 180 (measured as in the study), and are either age 75 or older or have a high risk of stroke or heart or kidney disease, then you have a new option to consider.
For the many people treated for blood pressure who would not have qualified for this study, including those with diabetes, it is not clear that they should do anything different. A healthy lifestyle that includes salt in moderation, daily physical activity, adequate sleep and weight control remain the tenets of avoiding high blood pressure.
Second, the potential benefits of lowering blood pressure must be weighed against harms.
The study found potentially lifesaving benefits: There was one bad health event avoided, including heart attack or stroke, for about every 200 people treated per year, and the results suggested one death was avoided for every 300 people treated per year.
The benefit, however, was offset a bit by some increased risk. As expected, treating people with more medications to achieve a lower blood pressure caused some harm. People who were treated more intensively also experienced more fatal or life-threatening events, including very low blood pressure and fainting. A surprise of this study was that intensive treatment could also increase the risk of kidney failure. Over the 3.3 years of follow-up, for every 100 people treated to achieve the lower blood pressure, one more person suffered life-threatening low blood pressure, one more fainted and two more had severe kidney problems.
The study opens a new option for treatment, but it is not a slam dunk that everyone who fits the eligibility criteria of the study ought to be treated. It is a choice that is worthy of thought and reflection.