The Hypertension Paradox

In the August 27 issue of The New England Journal of Medicine, Dr Aram Chobanian discusses what he calls the hypertension paradox—the fact that while therapy and outcome in hypertensive patients has improved dramatically, the total number of hypertensive patients and the numbers who are uncontrolled have increased over the past 20 to 30 years. ¹ But perhaps the paradox is less than Dr Chobanian claims.

He reviews initial therapies in the 1940s and 1950s that lowered blood pressure (BP) but were difficult to administer and produced annoying and often dangerous side effects. He notes the dramatic decrease in cardiovascular and cerebrovascular events in hypertensive patients whose BP has been controlled but notes that, despite these advances, the number of hypertensive patients has increased from 50 million in the 1988–1994 period to 65 million in the latest analyses in 2004. He neglects to mention that major reasons for this increase may be that reporting and screening for elevated BP have improved considerably over the past 20 to 30 years and that the definition of the most common form of hypertension, ie, isolated systolic hypertension, was changed during this period.

When the First Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure was published in 1977 ² and during the next 5 to 10 years, isolated systolic hypertension in the elderly was defined as >160/<90 mm Hg. During subsequent years the definition was changed. Isolated systolic hypertension is now defined as >140/<90 mm Hg. Needless to say, this change in definition dramatically increased the number of patients classified as hypertensive. When the criterion for the diagnosis of diabetes was changed from a blood sugar level of 140 mg/dL to 126 mg/dL, the number of patients classified as diabetic increased dramatically as well.

The statistics quoted in Dr Chobanian’s article that only one third of hypertensive patients have achieved goal levels of 140/90 mm Hg and that 39% are not receiving any therapy, are more than 5 years old. Recent statistics from a Harris Poll in 2007 ³ and from the Behavioral Risk Factor Surveillance Survey ⁴ report that more than 90% of hypertensive patients are being treated with specific medications and that more than 50% are controlled. We indeed are making progress. Do we have to improve treatment? Of course. We should continue to foster more efforts to control BP in more people and reduce cardiovascular events still further, but we should not forget the progress that has been made. ⁵

The positive should be emphasized. The trend for improvement in outcome as well as control is clearly a positive one. Thus, the paradox may not be nearly as great as Dr Chobanian suggests.