2009 Short Clinical Summary
Hypertension is one of the major health issues facing our country. In 2005, 5.7 million Canadians had been diagnosed with hypertension and just over 5 million were on pharmacotherapy. For the last decade, hypertension has been the leading diagnosis for adult visits to physicians and the proportion of total visits to a physician for hypertension are increasing 1. The World Health Organization has indicated that increased blood pressure is the leading risk for death, predicting an epidemic of hypertension and is advocating for prevention and treatment programs as a priority 2. Worldwide over 7 million deaths in the year 2000 were attributed to sub optimum blood pressure 3.
2009 marks the 10th consecutive year that the Canadian Hypertension Education Program (CHEP) has updated recommendations for the management of hypertension. CHEP was developed to enhance clinical management of hypertension and hence reduce the burden of cardiovascular disease in Canada 4. Recent data have suggested Canada is likely the world’s leading country in the prevention and control of hypertension with a five fold increase in treatment and control of hypertension in Ontario between 1992 and 2006 5 and a large increase in treatment of hypertension and reduction in cardiovascular disease rates that occurred at the time CHEP was initiated 6.
The CHEP program has continued to evolve over the last decade and in many cases can now identify specific clinical scenarios that require improvement in clinical care 7-9. This year CHEP focuses on reducing death and cardiovascular disease in people with diabetes by encouraging health care professionals to ensure their patients’ blood pressure is maintained less than 130/80 mmHg. New Canadian data indicate a minority of people with diabetes and hypertension are achieving adequate control of their blood pressure and thus continue to incur avoidable deaths and disability 10.
The 2009 CHEP theme is: Hypertension in the patient with diabetes
Up to 80% of people with diabetes die of cardiovascular disease and many diabetic complications are attributable to elevated blood pressure 11. Although elevated blood glucose levels is a cause of kidney and eye disease, elevated blood pressure in people with diabetes is also a major cause of kidney failure and eye disease 12, 13. Most people with diabetes have hypertension and almost 1 in 5 people with hypertension have diabetes 10.
Treating hypertension in people with diabetes is one of the most cost effective medical interventions available to reduce death and disability 14. Reduction in death and major cardiovascular event rates of more than 50% can occur in people with diabetes and hypertension whose blood pressure is treated 15, 16. Even more intensive hypertension treatment reduces death and cardiovascular events by 25% compared to conventional treatment levels 17. Hypertension treatment also reduces the progression of diabetic retinopathy and kidney disease 18 19 20 12, 13, 21.
The recently completed Heart and Stroke Foundation survey of blood pressure awareness treatment and control from the Province of Ontario found unprecedented levels of blood pressure control with 2 out of 3 people with hypertension under control. However, for people with diabetes rates of control were only 1 in 3, with 2/3rds above the target of less than 130/80 mmHg 10. This lack of blood pressure control in people with diabetes may be in large part due to the relatively low use of diuretic therapy – the cornerstone of treatment for resistant hypertension in this population22-24.
Combinations of lifestyle modification and 3 to 4 or more drugs may be required for blood pressure control in persons with diabetes 25. The prescription of an angiotensin converting enzyme inhibitor (ACE inhibitor) or angiotensin receptor blocker is recommended in all people with diabetes who are hypertensive (table 1) [CHEP 2009 Recommendations submitted to CJC for publication]. Alternative first line treatments include long acting calcium channel blockers and low dose diuretics in people without proteinuria [CHEP 2009 Recommendations submitted to CJC for publication]. If the blood pressure is 150/90 mmHg or more consideration should be given to initiating therapy with a combination of two drugs. Diuretic therapy is generally necessary for blood pressure control when three or more drugs are used and reduces major cardiovascular events in people with diabetes to the same extent as other drug classes 26. Maintaining normal serum potassium levels is important to lessen the impact of diuretics on blood glucose and maximize cardiovascular event reductions 27, 28. If blood pressure control is not achieved with sequential addition of antihypertensive drugs consider referral to a expert in hypertension. Of note quality of life improved in the people treated to lower blood pressure levels in the largest trial examining intensive vs. less intensive blood pressure lowering 29.
What’s new
In 2008 there were several new clinical trials of interest to clinicians. The ONTARGET trial found that an ACE inhibitor or an angiotensin receptor blocker had similar cardiovascular outcomes when prescribed to people with cardiovascular disease or type II diabetes 30, 31. The ONTARGET trial also found that while the combination of an ACE inhibitor with an angiotensin receptor blocker had some extra blood pressure lowering it had more side effects such as hyperkalemia, hypotension and renal impairment and did not improve patient outcomes compared to the ACE inhibitor alone. In people with stage 3 chronic kidney disease (GFR > 30 ml/min) the combination of an ACE inhibitor with an ARB reduced urine protein levels but did not reduce cardiovascular outcomes and did increase adverse renal outcomes including the need for acute dialysis compared to the ACE inhibitor alone 31.
The only data to support improved patient outcomes from the combination of an ACE inhibitor with an angiotensin receptor blocker is in people with heart failure where the combination reduces recurrent hospitalization. There are ongoing trials of combination of an ACE inhibitor with an angiotensin receptor blocker in people with chronic kidney disease and diabetes. Hence the use of combination of ACE inhibitor and ARB therapy should only be considered in selected and closely monitored people with advanced heart failure or proteinuric nephropathy (table 1). For people already on the combination and stable, clinicians need to consider that prescribing just one of the two classes reduces cardiovascular events to the same extent and that other therapeutic regimes have the potential to reduce cardiovascular events and blood pressure to a greater degree.
In 2008, the HYVET trial found large reductions in cardiovascular events and mortality in the treatment of hypertension in quite healthy but very elderly people (over age 80) 32. Hence CHEP now specifically recommends that age not be used as a factor in prescribing pharmacotherapy for hypertension [CHEP 2009 Recommendations submitted to CJC for publication]. Nevertheless CHEP continues to recommend caution in treating hypertension in frail elderly people where the risks of therapy and hypotension are likely to be higher. People where the risk may outweigh the benefit could include those with postural hypotension, post prandial hypotension and people who have a poor short term prognosis due to competing co-morbidity.
Other major clinical trials with angiotensin receptor blocker based therapy to lower blood pressure were considered (PROFESS 33 and TRANSCEND 34) but did not result in changes to the CHEP recommendations.
Home measurement of blood pressure
CHEP continues to encourage home measurement of blood pressure as a step towards greater patient self efficacy. Home blood pressure readings have a stronger association with cardiovascular outcomes than readings taken in a health care professional’s office. Home readings can be used to confirm the diagnosis of hypertension, improve blood pressure control, reduce the need for medications in those with white coat effect, identify those with white coat and masked hypertension and improve medication adherence 35. Patient instructions for purchasing and using home blood pressure measurement can be found at www.hypertension.ca and www.heartandstroke.ca/BP. In 2009 a home measurement instructional DVD will be available for download from the hypertension.ca site. General sources for patient information on home measurement of blood pressure can be found in Table 2.
Other important recommendations for the management of the patient with hypertension:
Assess blood pressure at all appropriate visits. Blood pressure increases with age such that 50% of Canadians over age 65 have hypertension. For those with normal blood pressure at age 55-65, over 90% will develop hypertension within an average lifespan. To identify those with hypertension all adults require ongoing assessment of blood pressure throughout their lives and those with high normal blood pressure require annual assessment.
Assess and manage overall cardiovascular risk in all people with hypertension including: smoking, dyslipidemia and dysglycemia (e.g. glucose intolerance, diabetes), abdominal obesity, unhealthy eating and physical inactivity. The vast majority of Canadians with hypertension have other cardiovascular risks. Identifying and managing risk factors in addition to hypertension can double the risk reduction in cardiovascular disease, can alter the blood pressure target (Table 3) and specific classes of medications recommended (Table 1). Currently only one half of younger people diagnosed with hypertension are treated even if they have multiple cardiovascular risks and those who smoke are less, rather than more, likely to be treated 9. Younger people with hypertension and multiple cardiovascular risks (male, sedentary behaviour, poor dietary habits, obesity, smoking etc.) are recommended to be considered for pharmacotherapy [CHEP 2009 Recommendations submitted to CJC for publication]. In general, people with hypertension who smoke and cannot quit are recommended to be prescribed antihypertensive therapy, although a beta-blocker should be avoided as first-line therapy in these people.
Sustained lifestyle modification is the cornerstone for the prevention and management of hypertension and cardiovascular disease (CVD). Hypertension can be prevented and treated, and other cardiovascular risks reduced, through healthy eating, regular physical activity, low risk alcohol consumption, reductions in dietary sodium and in some, stress reduction (Table 4). Unfortunately after a diagnosis of hypertension, few Canadians improve their lifestyle 8. However, simple, brief health care professional interventions increase the probability of a patient making lifestyle changes 36. Table 5 provides tips that can be used to advise people on how to reduce dietary sodium. Table 6 outlines internet resources that can assist people self management their care. A new section of the Heart and Stroke Foundation website (www.heartandstroke.ca/BP) has recently been designed to assess hypertensive patient’s lifestyles and provides individualized approaches and monitoring to assist lifestyle changes. Several patient handouts on hypertension can also be ordered from www.hypertension.ca/bpc.
Treat to target (<140/90 mmHg; <130/80 mmHg in people with diabetes or chronic kidney disease). Greater reduction in cardiovascular disease is achieved by lowering the blood pressure to the stated targets (Table 3). In people with diabetes and hypertension, lowering blood pressure to less than 130/80 mmHg markedly decreases cardiovascular death and hospitalization.
Combinations of therapies (both drug and lifestyle) are generally necessary to achieve target blood pressures. Most people require multiple antihypertensive drugs as well as lifestyle changes. When using two drugs to lower blood pressure combinations of a beta blocker, ACE inhibitor or angiotensin receptor blocker produce less than additive hypotensive effect and should be avoided unless there is a specific indication. If blood pressure is > 20/10 mmHg above target initiating therapy with a combination of two ‘first line’ antihypertensive drugs is a first line option.
Monitor people whose blood pressure is above target at least every 2 months. To achieve blood pressure control, follow-up at short intervals improves patient adherence and is required to increase the intensity of treatment.
Focus on adherence. Adherence to pharmacotherapy and lifestyle change should be routinely assessed at each visit. Health care professional interventions can both prevent non adherence and improve adherence in those who are having problems (Table 7).
Comments from the CHEP executive
CHEP works closely with the College of Family Physicians of Canada, Canadian Council of Cardiovascular Nurses, Canadian Pharmacists Association, Heart and Stroke Foundation, Public Health Agency of Canada, Statistics Canada and other organizations to improve hypertension prevention and control. In particular CHEP is working closely with Blood Pressure Canada to develop and disseminate patient information on hypertension to improve patient self efficacy in managing hypertension. A major recent activity has been to develop a joint committee with Blood Pressure Canada to produce patient and health care professional aids for reducing dietary sodium. The effort to prevent hypertension by a reduction in dietary sodium could reduce cardiovascular events by 13% 37 and could save over a billion dollars in health spending a year.
Although the effort to improve hypertension management has been associated with large reductions in cardiovascular disease, hypertension remains a major health risk to Canadians 6. Two thirds of diabetic Ontarians (and likely other Canadians) who are hypertensive have uncontrolled blood pressure. People with diabetes and hypertension represent one of the highest cardiovascular risk groups for primary prevention and also have the greatest potential benefit from lowering blood pressure. It is also concerning that the numbers of cardiovascular risks younger hypertensive Canadians have does not impact on whether they receive drug treatment for hypertension. Further hypertensive Canadians who smoke are even less, rather than more, likely to be treated for hypertension 9. While lifestyle therapy alone is appropriate for young people with hypertension who are at low cardiovascular risk, the majority has multiple cardiovascular risk factors and are strong candidates for pharmacotherapy. Perhaps, even more concerning is that after being diagnosed with hypertension, Canadian people only make very minor improvements in lifestyle and on average even gain weight 8. More emphasis on lifestyle change is required. Hopefully health care reform with an increase in primary health care teams will have a substantial impact on improving lifestyles of Canadians with hypertension.
A detailed survey of Canadians with hypertension is being conducted in 2009 to determine their knowledge, attitudes, beliefs and behaviors and in 2010 the results of a national blood pressure survey will indicate the Canadian rate of treatment and control. The surveys will indicate and document the areas of hypertension management that require improvement and will be used to develop more effective educational interventions for health care professionals and their patients. In the mean time Blood Pressure Canada has developed a new resource to aid interdisciplinary health care professional teams educate people about hypertension, lifestyle changes and home measurement of blood pressure (Brief Action Tool at www.hypertension.ca/BPC)
In 2009, a national strategy for prevention and control cardiovascular disease in Canada will be released. The strategy will provide guidance for prevention and control of hypertension in the context of reducing cardiovascular disease. CHEP anticipates that if implemented the strategy will lead to greater government involvement and a much greater reduction in cardiovascular disease in Canada.
The CHEP executive would like to thank the over 100 health care professional volunteers, many of whom spend hundreds of hours each year and have been involved for a decade now in developing, disseminating and evaluating the annual Canadian recommendations for the management of hypertension (Table 8). The collaborative approach of volunteers from clinic practice, academia and governments with the support of the primary care professional associations, the pharmaceutical health care industry, governments, charities and scientific organizations has been associated with marked improvements in the management and outcomes of hypertensive Canadians.