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Medicine management: Hypertension

Medicine management: Hypertension

Over 9 million people died as a consequence of high blood pressure in 2010. The Global Burden of Disease study, published in The Lancet in December 2012, revealed that out of the three leading causes of premature death worldwide (high blood pressure, alcohol and smoking), blood pressure is the biggest problem.1
High blood pressure is usually symptomless and often not regarded as a disease in its own right. However, it is a major risk factor in a number of potentially fatal conditions and is also a precursor to several non-fatal but debilitating disorders.
The main potential consequences include:

 - Coronary heart disease (angina, heart attack).

 - Stroke (thrombotic and haemorrhagic).

 - Heart failure (heart strain – especially left ventricular).

 - Chronic kidney disease (including established renal failure).

 - Aortic aneurysm (dilated aorta with risk of massive internal haemorrhage).
 - Retinal disease (visual impairment).

 - Peripheral vascular disease (clogged blood supply to the limbs).2
The risks associated with high blood pressure increase in parallel with a rising level of blood pressure. 
This increase in risk is gradual and continuous – there is no sudden step-up in risk with rising blood pressure. ‘Hypertension’ is a persistently raised blood pressure above a designated threshold.2 With each 2 mmHg rise in systolic blood pressure there is a 7% increased risk of mortality from ischaemic heart disease and a 10% increased risk of mortality from stroke. Hypertension is remarkably common in the UK and the prevalence is strongly influenced by age.3
Hypertension is defined by the National Institute of Health and Care Excellence (NICE) as follows3:

 - Stage 1 hypertension. Clinic blood pressure is 140/90 mmHg or higher and subsequent ambulatory blood pressure monitoring (ABPM) daytime average or home blood pressure monitoring (HBPM) average blood pressure is 135/85 mmHg or higher.

 - Stage 2 hypertension. Clinic blood pressure is 160/100 mmHg or higher and subsequent ABPM daytime average or HBPM average blood pressure is 150/95 mmHg or higher.

 - Severe hypertension. Clinic systolic blood pressure is 180 mmHg or higher or clinic diastolic blood pressure is 110 mmHg or higher.
A large-scale international study has shown that significantly increased risks of cardiovascular disease begin to appear at a level as low as 115/75 mmHg.4 This is far lower than the average adult blood pressure in the UK. For example, in England the average is 131/74 mmHg for men and 126/73 mmHg for women.5
The challenges
The clinical management of hypertension is one of the most common interventions in primary care, accounting for approximately £1 billion in drug costs alone in 2006,6 through the prescription of anti-hypertensive medication (ACE inhibitors, calcium channel blockers and diuretics). Hypertension causes more than 13% of all deaths across the world each year.
Prescribing – using the right drugs
Drugs should be chosen based on:
 - Age.
 - Ethnicity.
 - Comorbidities.
 - Use NICE algorithms to guide choice.

 - Follow up to ensure compliance and deal with any adverse effects.

 - Small doses of two drugs result in larger blood pressure (BP) reductions and fewer adverse effects than a maximal dose of one drug
Case Study: patient profile
Patient details:
Male aged 59
BMI: 30
BP: 190/110 
Current drugs: St Johns Wart (OTC)
Allergies/ADR: None                                                                
Lifestyle and social history:
Lives alone
Works as an accountant
Social drinker 30 units a week 
Smokes 20 cigarettes a day 
Q1. What lifestyle advice would you ask Mr SM to adopt?6
Exercise to reduce weight  as he has sedentary lifestyle.  
 - Smoking cessation.

 - Alcohol in moderation - he should try to maintain it at less than 21 units a week.

 - Dietary advice - reduce intake of fat and salt and increase his diet in complex carbohydrates such as potatoes, rice and other starchy foods, fruit and vegetables (to aim for five portions a day).
Q2. Would a blood pressure of 190/110 mgHg be considered as a diagnosis of hypertension? 
Diagnosing hypertension6

 - According to NICE guidelines CG127, if the clinic blood pressure is 140/90 mmHg or higher, ambulatory blood pressure monitoring should be offered; (ABPM) to confirm the diagnosis of hypertension.

 - Ensure that at least two measurements per hour are taken during the person’s usual waking hours (for example, between 08:00 and 22:00), if ABPM is used to confirm a diagnosis of hypertension.

 - To confirm a diagnosis of hypertension the average value of at least 14 measurements taken during the person’s usual waking hours should be used.

 - When using home blood pressure monitoring (HBPM) to confirm a diagnosis of hypertension, patient should be advised that:
For each blood pressure recording, measurements are taken twice, at least one minute apart with the person seated.
Blood pressure should be recorded twice daily, ideally in the morning and evening.
Patient continues recording blood pressure for at least four days, preferably for seven days.
Measurements taken on the first day should be discarded. The average value of all the remaining readings should be used.
Mr SM visits his GP after four months with a BP reading of 155/95 mmHg, with a 10-year cardiovascular risk equivalent to 25% and no target organ damage. Mr SM thinks the main causes of his rise in blood pressure are stress and food. It is worth noting a systemic review of qualitative research. Marshall et al. show lay perspectives about hypertension are often different from the medical viewpoint worldwide, people widely perceive that hypertension is principally a stress-related condition with symptoms and fear of addiction or dependence on drugs.7
Q3. What drug treatment if any would you give at this stage? 

 - Bendroflumethiazide or hydrochlorothiazides are no longer recommended as the thiazide-like diuretics. 

 - Continue treatment on bendroflumethiazide for people already on bendroflumethiazide whose BP is stable.

 - NICE recommends indapamide 1.5 mg MR once daily or 2.5 mg once daily or chlortalidone 12.5 mg to 25 mg.

 - Aim for once daily drug regimen wherever possible.8

 - If angiotensin – converting enzyme inhibitor (ACE-I) is not tolerated then give angiotensin receptor blocker (ARB). 

 - Do not use both ACE-I and ARB together there is no evidence of any additional benefits however an increased risk of side effects. 
It is good practice to: 
 - Use once daily agent.

 - Adjust at intervals of four weeks, to allow full response.

 - Titrate doses according to license (not thiazides).

 - Add drugs in stepwise approach until BP control is achieved (combination therapy is required in most patients).
 - Be aware that vitamins are of no benefit.
Q4. What target of BP should you aim for?
Q5. What BP monitoring devices are recommended? 
A list of validated blood pressure monitoring devices is available on the British Hypertensive Society at: Healthcare professionals using BP monitoring devices should be trained to do so.6 Blood pressure readings on both arms as part of initial assessment of hypertension is recommended by NICE, if there is a difference between both readings of >20 mmHg, the readings should be repeated. A cohort study by Clark et al. concluded that differences in systolic blood pressure between arms can predict an increased risk of cardiovascular events and all-cause mortality over 10 years in people with hypertension.9
There are concerns relating to the accuracy of diagnosis of hypertension and its impact on drug prescribing in terms of cost and appropriateness. Patient anxiety when presenting at the surgery can potentially lead to a misleading BP reading (known as ‘white coat hypertension’), often pushing the patient into the ‘high blood pressure’ zone, thus triggering the hypertension management pathway resulting in the patient being prescribed medication that may not be required, or at incorrect dosages. NICE has produced definitive guidelines so GPs can diagnose the condition more accurately, by giving those suspected of having high blood pressure a home monitoring device. Sifting out those people with ‘white coat hypertension’ (misdiagnosed) could reduce the £1 billion drug bill dramatically. NICE estimate the annual saving as a result of fully implementing the ambulatory blood pressure monitoring (ABPM) guidelines [to confirm the diagnosis of hypertension] in England to be £10.5 million by the fifth year after implementation.10
Improving self-monitoring to control BP within target levels
A group of UK primary care researchers found that patients who monitor their own blood pressure at home have small, but significant, reductions in pressures when measured in surgery. They carried out a systematic review of 25 randomised controlled trials of self-monitoring, which either measure systolic and diastolic pressures taken in surgery, or the proportion of patients who achieved a blood pressure target. The systematic review concluded that patients who self-monitored had blood pressures that on average were lower by 3.82 mmHg systolic and 1.45 mmHg diastolic compared to those who just had their pressures measured at routine visits. Self-monitoring increased the chance of meeting a blood pressure target by 9%.11
Self-monitoring of blood pressure may lead patients to discuss their blood pressure with their doctor and this may encourage appropriate prescription of antihypertensives. Self- monitoring makes patients more aware of their blood pressure level; this might increase their illness perceptions and subsequent health behaviours and therefore improve adherence to drugs.12 Of 11 randomised controlled trials of self-monitoring that reported measures of treatment adherence, six showed a statistically significant improvement in adherence, but in five of these six trials, self-monitoring was part of a complex intervention.13
Innovative approaches are being developed in areas of the country using telehealth to drive compliance with blood pressure self-monitoring. For example, the ‘Florence SMS texting’ service, which is a has been successfully developed and rolled out across 10 GP practices in NHS Stoke on Trent CCG involving 124 intervention patients. This simple telehealth approach prompts patients to take home blood pressure readings and text them to a secure server (‘Florence’) for immediate automatic analysis and individual healthcare professional review.14
The Florence SMS texting service has been developed over the last three years by NHS Stoke on Trent and trialled in around 25 primary care trusts and clinical commissioning groups across the UK – mainly in primary and community care settings (hypertension, asthma, COPD). 
The challenges associated with containing the costs of management for hypertension are linked to implementing cost effective strategies for controlling blood pressure within target levels. Self-monitoring is already used and recommended; evidence shows it can undoubtedly provide a more precise measure of mean blood pressure than intermittent clinic measurement. Controlled BP means better targeted drug treatment. Self-monitoring may have a knock-on effect on drug adherence, thus reducing waste. More accurate diagnosis, through the implementation of ambulatory blood pressure monitoring (ABPM), can help to reduce needless prescribing. l
Lozano R et a. A systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012;380:2095-128.
Maryon-Davis A, Press V. Easing the pressure: tackling hypertension. A toolkit for developing a local strategy to tackle high blood pressure. Faculty of Public Health and National Heart Forum. London: Faculty of Public Health; 2005.
NICE. NICE Guidelines CG127 – Hypertension: Clinical Management of Primary Hypertension in Adults. London: NICE; 2011.
Prospective Studies Collaboration. Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet 2002;360:1903-12.
Joint Health Surveys Unit. Health Survey for England 2003. Volume 2 Risk Factors for Cardiovascular Disease. London: The Stationary Office: 2004.
NICE. NICE Guidelines CG127 – Hypertension: Clinical Management of Primary Hypertension in Adults. London: NICE; 2011.
Marshall IJ et al. Lay perspectives on hypertension and drug adherence: systematic review of qualitative research. BMJ 2012;345:e3953.
Zhao P, Xu P, Wan C, Wang Z. Time effects of blood pressure lowering drugs for the treatment of high blood pressure. Cochrane Database of Systematic Reviews 2011, Issue 10. Art. No.: CD004184.
Clark CE, et al. The difference in blood pressure readings between arms and survival: primary care cohort study. BMJ 2012;344:e1327.
NICE. National costing report: Hypertension (August 2011) 9 of 27. 
Bray EP, et al. Does self-monitoring reduce blood pressure? Meta-analysis with meta-regression of randomised controlled trials. Annals of Medicine 2010;42(5):371-86(16).
McManus RJ et al. Clinical Review. – Blood Pressure Self-Monitoring: questions and answers from a national conference. BMJ 2009;338:38-42.
13. Ogedegbe G, Schoenthaler A. A systematic review  of the effects of home blood pressure monitoring on
medication adherence. J Clin Hypertens  2006;8:174-80.
14. Cottrell E, McMillan K, Chambers R. A Cross-sec tional survey and service evaluation of simple  telehealth in primary care: What do patients think?  BMJ Open 2012;2:e001392 doi:10.1136/bmjo pen-2012-001392.

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