Three in every four adults suffering from debilitating chronic diseases such as diabetes, stroke, kidney disease and heart failure also suffer from high blood pressure, according to a new study.
The research helps underscore just how devastating hypertension can be and why it is often described as a "silent killer."
The findings, published in today's edition of the Archives of Internal Medicine, also draw attention to how commonplace high blood pressure has become, and to the fact that while many patients are treated, getting blood pressure under control remains a challenge.
"You get high blood pressure by leading an unhealthy lifestyle, so it often goes hand in hand with chronic conditions," said Norm Campbell, president of Blood Pressure Canada.
He was not involved in the study, which was conducted by a team led by Nathan Wong of the University of California, Irvine.
The research showed that, over all, about one-third of adults in the United States had high blood pressure; Canada is believed to have a similar rate of hypertension.
The study found that the vast majority of people with chronic conditions affecting the cardiovascular system also suffered high blood pressure, including:
76.8 per cent of those with diabetes;
81.8 per cent of those with chronic kidney disease;
69.5 per cent of those with stroke;
71.4 per cent of those with congestive heart failure, which occurs when the heart is straining to pump enough blood throughout the body;
73.7 per cent of those with peripheral artery disease, or narrowed veins or arteries;
73 per cent of those with coronary artery disease.
Healthy adults should have a blood pressure of 120/80 millimetres of mercury (mmHg) or better. A person is considered hypertensive with a blood pressure reading of 140/90 or higher. Lower blood pressure can be achieved with lifestyle changes such as reducing salt intake, losing weight and exercising, and it can also be treated with prescription drugs.
The new study found that about two-thirds of U.S. patients with high blood pressure were being treated, but only half had their blood pressure under control. Patients with the most severe health conditions, like heart failure and stroke, were least likely to have their blood pressure under control, according to the study.
Current comparative Canadian data are not available but are expected to be published in the coming months.
Dr. Campbell said that, generally speaking, "most countries are struggling with these same problems" and that, globally, high blood pressure is one of the leading causes of death.
For the new study, researchers analyzed data from 4,646 adult participants in the U.S. National Health and Nutrition Examination Survey, a massive ongoing research project.
About five million Canadians are estimated to suffer from high blood pressure.
André Picard