Hypertension paradox

What is the paradox?

Dr Aram Chobanian, a world-renowned cardiologist and the Dean of the Boston University Medical School, wrote in the NEJM special article that despite the remarkable successes in lowering blood pressure in patients with hypertension, the prevalence of hypertension continues to increase worldwide. The number of people with uncontrolled blood pressure is also increasing.

He reviewed the development of the anti-hypertensive drug therapy and other evolving approaches such as lifestyle modifications. He recommended a new treatment algorithm for the management of stage 1 and 2 hypertension.

He noted that recent data indicated that about 28% of Americans with hypertension are unaware of their condition, 39% are not receiving treatment and 65% do not have their BP controlled. The controlled rates are even worse in patients with chronic kidney disease, diabetes, and other cardiovascular dysfunction in whom target BP levels of 130/80 mm Hg are recommended.

With the prevalence of hypertension continues to increase worldwide, he asked “what can be done to reverse this trend”. He pointed out that “salt intake and body weight are particularly important in the age-related increase in BP” but some countries such as Finland and GB have achieved significant reductions in dietary sodium through aggressive efforts including education and working with the food industry.

He said that “the failure to adopt healthy lifestyles has been a critical factor in this increase” and must be addressed urgently. He urged a national strategy to promote physical activities combined with changes in dietary intake.

This article was presented as the Shattuck lecture of the Massachusetts Medical Society and available as open access at the NEJM website.

Source: “The Hypertension Paradox — More Uncontrolled Disease despite Improved Therapy” NEJM 2009, 361(9):878-887

Conventional blood pressure test has no prognostic value

Researchers enrolled 556 people aged 65 on average who had high blood pressure despite having been treated with anti-hypertensive drugs and followed up for 4.8 years to determine which form of blood pressure monitoring was a better predictor of risk of cardiovascular disease in people with medication-resistant high blood pressure.

They found that conventional surgery-measured BP did not predict strokes or heart attacks, but readings taken over 24-hour period could. Critics say conventional blood pressure testing by a GP remains essential and is invaluable in detecting and monitoring high blood pressure that often has no symptoms and is difficult to detect.

Source: Salles GF, Cardoso CRL, Muxfeldt ES. Prognostic Influence of Office and Ambulatory Blood Pressures in Resistant Hypertension. Archive of Internal Medicine 2008; 168: 2340-2346
(f/t via Athens)

Poor sleep links to heart disease

In a study of 1,255 Japanese adults with high blood pressure aged 70.4 in average, researchers recorded each participant's blood pressure changes over 24-hour period and followed them for about 50 months.

During the follow-up, there were 99 cardiovascular disease events, they also found that participants who slept less than 7.5 hours a night had 68% high risk of one of these complications than those who had longer sleep.

They also found that the risk was higher among participants who also had an increase in overnight blood pressure than those who did not have an increase in blood pressure. Researchers concluded that "shorter duration of sleep is a predictor of incident cardiovascular disease in elderly individuals with hypertension, .......Physicians should inquire about sleep duration in the risk assessment of patients with hypertension."

Source: "Short Sleep Duration as an Independent Predictor of Cardiovascular Events in Japanese Patients With Hypertension" Arch Intern Med. 2008;168(20):2225-2231 (f/t via Athens)

Anti-hypertension drug types do not influence outcome

Previous studies suggest that the effects of anti-hypertensive drugs might be smaller among elderly people and some guidelines recommend specific types of blood pressure lowering treatment for particular age groups.

According to the BMJ, a new meta-analyses of 31 trials with more than 190,000 participants "showed no clear difference between age groups in the effects of lowering blood pressure or any difference between the effects of the drug classes on major cardiovascular events, .... also showed no difference in effects between the two age groups for the outcome of major cardiovascular events".

Source: "Effects of different regimens to lower blood pressure on major cardiovascular events in older and younger adults: meta-analysis of randomised trials -Blood Pressure Lowering Treatment Trialists’ Collaboration" BMJ 2008;336:1121-1123 ( free f/t)

Elderly should be offered hypertension drugs

Some previous studies have suggested that the over-80s may be harmed by the hypertension medication, but the Daily Mail reported that a major study by Imperial College London found the opposite.

The study looked at 3,845 patients from 13 countries with an average age of 83 and had high blood pressure and the use of one particular type of diuretic blood pressure medication. Within a year of treatment, there was a 21% reduction in death rates and 64% drop in heart failure, 39% drop in stroke deaths and 34% reduction in cardiovascular events.

Source:"Treatment of Hypertension in Patients 80 Years of Age or Older" New England J of Medicine. March 31, 2008 (10.1056/NEJMoa0801369)

Vaccine can cut high blood pressue

The Guardian and other news source reported that a team of Swiss scientists has developed a vaccine that targets angiotensin II to reduce blood pressure significantly.

The findings, published in The Lancet, were based on a 14 week multicentre, double-blind, randomised, placebo-controlled trial involving 72 patients with mild-to-moderate hypertension. The patients received randomly injections of either 100 μg or 300 μg of the vaccine or placebo.

The researchers found that systolic and diastolic blood pressure fell by 9mm and 4mm respectively in patients given 300 μg of the vaccine, especially in the morning, but no change in blood pressure in the placebo group. They said the findings were promising but large-scale trials were needed.

Source: "Effect of immunisation against angiotensin II with CYT006-AngQb on ambulatory blood pressure: a double-blind, randomised, placebo-controlled phase IIa study" The Lancet 2008; 371:821-827 Number 9615 ( full text via Athens)