Fewer Americans over age 60 could be taking blood pressure medications under new U.S. guidelines that a journal editorial notes may be controversial.

Wednesday's online issue of the Journal of the American Medical Association (JAMA) includes the 2014 U.S. guidelines on when and how to treat elevated blood pressure. Controlling blood pressure is important for preventing heart attacks and strokes as well as congestive heart failure and chronic kidney disease.

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New U.S. guidelines for treating blood pressure say people 60 or older should start pharmacologic treatment when their systolic or top reading reaches 150. (Bruce Smith/Associated Press)

The major change in the new U.S. guidelines is people 60 or older should start pharmacologic treatment when their  systolic or top reading reaches 150, said Dr. Paul James of the University of Iowa, one of the guideline authors. The previous recommendation was to start treatment at 140.

What the U.S. guidelines have done is liberalized the goal of therapy, said Dr. Beth Abramson, a cardiologist in Toronto and a spokeswoman for the Heart and Stroke Foundation of Canada.

In contrast, in Canada, the latest guidelines in October use age 80 as the cutoff for a systolic of 150 because doctors don't want blood pressure to fall too much for this age group, Abramson said.

Patients over age 60 are often taking multiple medications, so reducing their medication "burden" is a consideration, James said. The possibility of overtreatment with lower blood pressure goals is another factor.

"An elderly person who may get dizzy when they stand up, they will have a higher risk of falling and that has additional health consequence," James said in an interview.

The recommendation concerning those over age 60 is the only one based on good, reliable data, said Dr. Salim Yusuf, executive director of the Population Health Research Institute at McMaster University in Hamilton.

Most are based on expert opinion, which points to gaps in our knowledge, both Yusuf and Abramson said.

The guideline authors also point to a lack of clear evidence from randomized control trials to explain why the European Society of Hypertension uses age 80 as Canada does.

"Even though these guidelines are generally based on a rigorous assessment of the available clinical trial evidence for treatment of high blood pressure, some elements of these guidelines may be controversial and most likely will spark discussion," Dr. Howard Bauchner, the journal's editor in chief, and his fellow editors said. 

The new U.S. guidelines also standardize the goal to less than 140/90 for anyone under 60, or people with diabetes or chronic kidney disease.

"For all persons with hypertension, the potential benefits of a healthy diet, weight control, and regular exercise cannot be overemphasized," James and his guideline co-authors concluded. "These lifestyle treatments have the potential to improve [blood pressure] control and even reduce medication needs."

Canada's guidelines are focused on lifestyle in addition to medication, Abramson said.

Unlike Canadian and other international guidelines, the U.S. guidelines don't include how to measure blood pressure, said Dr. Martin Myers, a cardiologist at Sunnybrook Health Sciences Centre in Toronto who has been involved in writing the Canadian guidelines for 30 years.

Under the "white coat" effect, blood pressure is often higher when measured by a doctor or a nurse in an office compared to when no one is looking, a difference that can be addressed using 24-hour monitoring.

"That's one of the reasons why office blood pressure in the other guidelines, including Canada, has been downgraded," Myers said. 

Canadian guidelines also take a broader picture on blood pressure by considering other cardiovascular risks, Myers added.

The Canadian threshold of 140 systolic is for people under age 80 at high risk because they've had a heart attack, stroke or organ damage, said Dr. Raj Padwal, a professor of medicine at the University of Alberta in Edmonton and a spokesperson for Hypertension Canada.