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Hypertension and the role of the practice nurse

Rachael Sian Tyrrell
BN(Hons) RGN
Nurse Specialist in Hypertension and Cardiovascular Risk
Department of Cardiology
Wales Heart Research Institute University of Wales College of Medicine
Cardiff
E:tyrrells@cardiff.ac.uk

Hypertension is a chronic condition and a major public health problem.(1) It should not be regarded so much as a disease, but more as one of three treatable or reversible risk factors for premature death due to arterial disease.(2)
In spite of the proven beneficial effects of treatment in reducing levels of morbidity and mortality, the 1998 Health Survey for England concluded that hypertension is significantly underdiagnosed and undertreated.(3) It is estimated that up to 20% of the population have hypertension, making it one of the most common medical conditions in the UK.(4) The "rule of halves" dictates that currently only 50% of hypertensive patients will be diagnosed. Of those, only 50% will receive antihypertensive therapy, and of those only 50% will have adequate blood pressure control.(5)
The condition is widely regarded as a silent killer, as many patients present symptom-free and feeling generally well. Hypertension is a major risk factor for cardiovascular and cerebrovascular disease, both recognised as major causes of death in the UK and the rest of the Western world.(6)
Any attempt to deliver an appropriate philosophy of care for managing hypertensive patients should adopt a holistic approach. Such an approach should involve patients in identifying other risk factors they may have, as well as educating them about the potential benefits of antihypertensive treatment.(7)
Trained nurses have an important role to play in hypertension management and patient education, and can help to reduce the burden of disease by adopting a global approach to risk factor and lifestyle management, as well as detecting potential side-effects from treatment.(8)

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Defining hypertension
To date there are no universally accepted criteria that define hypertension. However, some clinicians regard the most appropriate definition of hypertension as being "that level of blood pressure above which investigation and treatment do more good than harm".(2,5)  The World Health Organization (WHO) defines hypertension as a systolic blood pressure (SBP) of 140mmHg or more and/or a diastolic blood pressure (DBP) of 90mmHg or more in those who are not on antihypertensive therapy.(9)
In nondiabetics, the British Hypertension Society (BHS) recommends the initiation of antihypertensive therapy in those with a sustained SBP greater than 160mmHg and a DBP of 100mmHg. In diabetic patients, it recommends commencing antihypertensive treatment if there is a sustained SBP of 140mmHg or above and a DBP of 90mmHg or above. While the BHS has recommended optimal BP targets for diabetics and nondiabetics, they acknowledge that, despite best practice, these levels may be difficult to achieve, particularly in patients with diabetes and/or hypertension.(10) Recent evidence suggests that individuals with normal and high-normal blood pressure frequently become hypertensive over a period of four years, especially older adults. Consequently blood pressure monitoring is recommended yearly for those with high-normal blood pressure and every two years for those with normal blood pressure.(11)
 
Assessment of the hypertensive patient
"No two patients are alike, and where blood pressure is concerned management should be tailored to the individual."(7) A thorough assessment should take into account other risk factors, which may contribute to increasing a patient's overall cardiovascular risk, and not simply look at the level of blood pressure.(5) The primary aim in any assessment should be to confirm a diagnosis of raised blood pressure. Single readings do not confirm hypertension, but merely indicate the need for further monitoring, unless there is clear evidence of end-organ damage such as hypertensive retinopathy or cardiovascular disease.
Moreover, evidence suggests that practice nurses (PNs) appear less threatening to patients and are therefore ideally suited to establish effective partnerships with their patients. This can help to reduce patient anxiety and to allay fear, which may be associated with a diagnosis of hypertension.(4,12) The diagnosis can cause patient distress, and the importance of explaining that it is not a disease cannot be underestimated, especially in terms of helping patients become more compliant with their treatment.(4,13)
Table 1 describes some common signs of hypertension and the investigations needed to confirm a diagnosis of raised blood pressure.

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Primary or essential hypertension accounts for 95% of all blood pressure. Often there is no underlying cause, although it is associated with the coexistence of other risk factors.(15)
Dietary and lifestyle modification can be implemented in hypertensive patients and for blood pressure reduction in the rest of the population. These changes include weight loss, reduction of dietary salt, limiting alcohol consumption and increasing physical activity.(16)

Weight reduction
The benefits of weight reduction are not always ­appreciated by patients or healthcare professionals, particularly in terms of improving conditions like hypertension, hyperlipidaemia or diabetes.(17) A loss of 10kg in an overweight person can cause a 10mmHg reduction in both systolic and diastolic blood pressure and reduce their overall mortality risk by 20-25%.(18)
Weight loss and subsequent maintenance of an ideal body mass index are difficult goals for many individuals to attain. PNs are ideally suited to advise patients about lifestyle modification, but the advice and targets they set must be realistic.(19)
 
Dietary changes
Increasing evidence suggests that there is a strong relationship between salt and hypertension. Guidelines suggest that patients should be advised to aim for a dietary intake of less than 5.8g a day. They should also be advised not to add salt to their food and to avoid processed foods. Counselling by trained dieticians may be appropriate for many patients. Other dietary recommendations include increasing fruit and vegetable consumption, increasing oily fish intake and reducing their fat intake.(16)
Alcohol is known to raise blood pressure. Evidence suggests the greater the alcohol consumption, the higher the blood pressure. An intake of around 80g per day (four pints of beer) will cause a rise in blood pressure. Hyper­tensive patients should be advised to limit their alcohol intake, in line with the recommended levels.(5)
 
Physical activity
A regular programme of moderate aerobic exercise is a known contributory factor in reducing an individual's risk of coronary heart disease.(9) Those who take regular exercise are healthier and have lower blood pressure than those who take none.(2) Long-term health benefits of exercise also include effects upon an individual's general physical and ­mental wellbeing.(20)

Referrences

  1. Aminoff UB, Kjellgren KI. The nurse - a resource in hypertension care. J Adv Nurs 2001;35(4):582-9.
  2. Beevers DG, Macgregor GA. Hypertension in practice. London: Dunitz; 1999.
  3. Erens B, Primatesta P, eds. Health survey for England. Cardiovascular disease 1998. Vol 2. Methodology and documentation. London: The Stationery Office; 1999.
  4. McInnes G. Explaining ­hypertension and its risks to patients. Prescriber 2001;Jan 19:19-26.
  5. Beevers G, Lip GYH, O'Brien E. ABC of hypertension. London: BMJ Publishing Group; 2001.
  6. Lane DA, Lip GYH. Ethnic ­differences in hypertension and blood pressure control in the UK. QJM 2001;94:391-6.
  7. Beevers M. Patient profiling in hypertension. Practice Nursing 1998;9:35-8.
  8. Meredith P. Patients need more than antihypertensives alone. Practice Nursing 1998;9:31-3.
  9. World Health Organization - International Society of Hypertension Guidelines Subcommittee. Guidelines for the management of hypertension. J Hypertens 1999;17:151-83.
  10. Ramsay LE, Williams B, Johnston GD, et al. Guidelines for management of hypertension: report of the third working party of the British Hypertension Society. J Hum Hypertens 1999;13:569-92.
  11. Ramachandran SV, Larson MG, Leip EP, et al. Assessment of frequency of progression to hypertension in non-hypertensive participants in the Framingham Heart Study: a cohort study. Lancet 2001;358:1682-6.
  12. Chapman J, Bent M. Treatment of hypertension. Practice Nursing 1999;10:29-30.
  13. Beevers M. The role of nurses in the management of hypertension. Modern Hypertens Management 2000;1:11-3.
  14. Mahmud A, Feely J. Pseudo-systolic hypertension in young men - elastic not stiff arteries. J Hum Hypertens 2001;15:822.
  15. Cowley N. What is hypertension? Practice Nursing 1999;10:26-8.
  16. Lydadis C, Lip GYH, Beevers M, Beevers DG. Diet, lifestyle and blood pressure. Coronary Health Care 1997;1:130-7.
  17. A Report of the Royal College of Physicians of London. Clinical management of overweight and obese patients. London: Royal College of Physicians; 1998. p. 1-30.
  18. Jung RT. Obesity as a disease.Br Med Bull 1997;53:307-21.
  19. Daly G. Non-drug management of hypertension. Practice Nursing 1998;9:39-41.
  20. Roberts C, Banning M. Managing risk factors for hypertension in primary care. Nurs Standard 1998;12:39-43.

Resources
Cardiff Self-Referral Clinic
Website W:www.mrfc2000.fsnet.co.uk
British Cardiac Society
W:www.bcs.com
British Heart Foundation
W:www.bhf.org.uk
British Hypertension Society
W:www.hyp.ac.uk/bhs
Blood Pressure Association
W:www.bpassoc.org.uk