November 10, 2010

Undetected High Blood Pressure Linked To More Deaths From Heart Attacks

Research also reveals that in areas with more white people, greater deprivation, more smokers and more people with diabetes, there is an increased risk of dying from coronary heart disease

Your postcode could affect your risk of dying from a heart attack, a new study from the University of Leicester has discovered.

Medical researchers from the University set out to determine why death rates from coronary heart disease (heart attacks) varied around the country and found that living in a deprived area contributed to your risk.

The study has for the first time established an association at national level between detection of hypertension and death rates from coronary heart disease.

The Leicester team, from the Department of Health Sciences, analyzed whether variations in deaths between different parts of the country could be explained by characteristics of primary health care services (such as numbers of doctors, performance against national targets), as well as by characteristics of the population, such as deprivation, lifestyle (such as smoking), or the numbers of people with diabetes

Their findings have been published in the November 10 issue of JAMA.

Lead research and report author Dr. Steve Levene, of the University of Leicester and a city GP, said: "We found that population characteristics were most important, including deprivation; however, 10% of the variation was also explained by how successful primary care services are at detecting people who have high blood pressure (hypertension). People who have hypertension are at greater risk of having heart attacks. No other health service factor that we examined was associated with the variation. Our results were the same for 3 consecutive years, 2006, 2007 & 2008.

"We found that higher proportions of white individuals, higher levels of deprivation, higher levels of diabetes, higher proportions of smokers, and lower levels of detected hypertension were associated with higher levels of coronary heart disease mortality at Primary Care Trust level in our models. Interestingly, when diabetes, age, smoking, obesity and deprivation are taken into account, coronary heart disease death rates are higher in populations with a greater proportion of whites, rather than of non-whites.

"This is important because it suggests ways in which we can reduce deaths from coronary heart disease. Greater detection of hypertension may reduce deaths from heart attacks. However, it is important to recognize the importance of deprivation, obesity and smoking. People need to be aware of the value of having their blood pressure checked, along with other steps to stay healthy including not smoking and controlling their weight. Any policy to reduce coronary heart disease death rates will need to address these problems as well."

Dr Levene said the new study was important since it shows a practical way to reduce deaths from heart attack that can be implemented now at a relatively lower cost. It also suggests that medical practitioners and policy makers need to make better contact with the whole population, rather than just those individuals whose diseases are known about.

Researchers will now make initial plans for a local program to improve hypertension detection. This could lead to lower deaths in Leicestershire, Northamptonshire and Rutland in the future.

Professor Richard Baker, one of the co-authors and Director of the CLAHRC said: "This would provide an example for other parts of the country, and other countries, on what can be achieved through simple, low cost measures. There is an urgent need for an effective program, as the city of Leicester has one of the highest death rates from heart attacks in England."

The University of Leicester was the only institution involved in the research.

The study was undertaken over the past year using readily available data. Dr Levene took a sabbatical from his practice for 3 months in 2009, joining the NIHR CLAHRC for LNR to undertake this work. CLAHRC is the NIHR Collaborations for Leadership in Applied Health Research and Care .http://www.nihr.ac.uk/infrastructure/Pages/infrastructure_clahrcs.aspx

Hypertension is a common condition, affecting 30% or more of the adult population. Coronary heart disease is a very common cause of death; the rate of deaths from coronary heart disease has fallen in recent years, but the paper shows that we can do even more to reduce the numbers of deaths and to reduce variations between the best and worst areas of the country.

Although mortality from coronary heart disease (CHD) has been steadily decreasing since the 1970s, it is still responsible for 15 percent of all deaths and nearly half of all circulatory disease deaths in England. A national policy was launched in 2000 to reduce the CHD mortality rate by two-fifths in those individuals aged younger than 75 years by 2010. This goal was achieved nationally, but regional variations in CHD mortality rates persist," according to background information in the article.

The study included all 152 primary care trusts (total registered population, 54.3 million in 2008) and analysis of data regarding CHD mortality and population characteristics (including an index of multiple deprivation [low measures on economic, social and housing issues], smoking, ethnicity, diabetes) and service characteristics (level of provision of primary care services, levels of detected hypertension, pay for performance data).

The average age-standardized CHD mortality rates per 100,000 European Standard Population decreased from 97.9 in 2006 to 93.5 in 2007 to 88.4 in 2008. Analysis indicated that in all 3 years, 4 population characteristics were significantly positively associated with CHD mortality: index of multiple deprivation; smoking, white ethnicity, and registers of individuals with diabetes. Only one service characteristic, the level of detected hypertension, was significantly negatively associated with CHD mortality. The median (midpoint) proportion with detected hypertension appears to have increased gradually between 2006 and 2008.

JAMA 2010;304[18]:2028-2034


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