After smoking cessation, the control of hypertension should be one of our main targets when it comes to positive health measures for our practice population. This was encouraged by the Health of the Nation and most GPs now have a recent blood pressure record on the majority of their adult patients.
Over the past few decades, increasingly effective treatments have been introduced, with attention paid to minimising unwanted side-effects. The treatment of hypertension has moved from specialised clinics to the GP consulting room.
With better control of blood pressure it was not clear initially why the myocardial infarction and stroke risk were not reduced. It seems that this may have resulted from inappropriate diagnostic criteria, and there is now good evidence that better control results in better outcomes.1
Long before the medical profession managed to get their act together, actuarial figures demonstrated a clear linear relationship between level of blood pressure and excess mortality for age (i.e. the relationship continues even in the so-called normal range). It should therefore come as no surprise that successive guidelines give lower and lower targets for blood pressure control.
The new World Health Organisation International Society of Hypertension (WHOISH) guidelines2 set new targets of 130mmHg for systolic pressure and 85mmHg for diastolic pressure for young, middle-aged and diabetic hypertensive patients.
The guidelines, as released, are aimed at specialists, but work is ongoing to produce a version for GPs. The British Hypertension Society guidelines are also due to be released shortly.
As with other guidelines, the only way to make them work is to take a team approach, and involve all the players. It may well be ideal to take this on at trust or primary care group (PCG) level, involving hospital clinicians as well as GPs, district and practice nurses, and also a pharmacist.
The PCG approach may be particularly pertinent at the moment, as it may reduce inconsistencies between practices and individual doctors in quality and cost of care.
Sources of information are plentiful, and it would be foolhardy to stray very far from a widely accepted guideline, but there is always room for 'tweaks'.
At a local level, you may decide to:
- Include specific drugs rather than groups
- Clarify or initiate local initiatives for lifestyle modification
- Agree referral criteria.
In setting up guidelines within the practice, it is best to include all members of the primary healthcare team. The most basic details need to be discussed, and, when agreement is reached, be laid out in a clear written form, preferably with an associated algorithm.
A copy of the guideline needs to be on every desk, and preferably easily accessible on the computer. The guidelines should also be contained in an introductory pack for new registrars, assistants or locums.
- Standardisation of taking the reading.
- Which sounds do we record? (This dates me, as in recent years the disappearance of the Korotkoff sounds (phase V) has been taken as the diastolic pressure.)
- In what position do we place the patient to take the blood pressure? The usual position is with the patient seated, but this needs to be specified.
- How big a cuff do we use? We specify a cuff to enclose at least 80% of the circumference of the arm.
- Where do we position the arm?
- How accurately can we record blood pressure? It is felt that we can record accurately to the nearest 2mmHg.
- How many high readings confirm the diagnosis, or suggest that we should increase or alter the medication?
Arrangements should be clear about the regularity of follow-up, who will do this, and what will be done at each visit. In hypertension, watching for end-organ damage is an important part of monitoring, and it is all too easy to overlook the necessary checks when the patient sees different people on each occasion.
We have instigated a patient-held 'co-operation' card, which works like those used in antenatal care, and helps to avoid omissions. We have also split routine care between the practice nurse and the GP, with the GP seeing the patient once a year, and performing an eye and heart examination, and blood tests being performed by the nurse when the patient visits her.
One of the potential problems brought about by decreasing the threshold at which we diagnose hypertension is the likely increase in workload in treating and monitoring patients who come into the frame. This may well require us to alter our working habits and devolve more of the management of these patients.
If the guidelines are well construed, and there is ready support for nursing staff when necessary, this should not present major problems, although it may still have implications with regard to manpower.
The new WHOISH guidelines suggest using the lowest available dose of a single drug to initiate treatment, changing to a different class if there is very little response or poor tolerability to the first drug, before increasing the dose of the first drug or adding a second drug (see algorithm below).
|Extract from the 1999 World Health Organization International Society of Hypertension Guidelines for the Management of Hypertension (J Hypertens 1999; 17:151-83)|
They recommend the use of long-acting drugs to provide 24-hour efficacy on a once daily basis. This may provide greater protection against the risk of major cardiovascular events, and the development of end-organ damage, but is also likely to result in better compliance in a condition that has no symptoms.
The guidelines recommend the use of appropriate drug combinations to maximise efficacy and minimise side-effects. Fixed dose combinations are said to have possible advantages.
The majority of patients need two or more drugs for adequate control.
The recommendation of low-dose aspirin is thought reasonable in those whose blood pressure has been rigorously controlled, who are at high risk of coronary heart disease, and who are not at particular risk of gastrointestinal bleeding.
Even in hypertension clinics, guidelines are not always followed, even by their instigators. Audit is an essential tool in the monitoring of hypertension guidelines, and will enable us to improve our practice. It is educative, and reminds us to maintain the standards that we have set.
- Hansson L et al. Effects of intensive blood-pressure lowering and low-dose aspirin in patients with hypertension: principal results of the Hypertension Optimal Treatment (HOT) randomised trial. Lancet 351:1755-62.
- Chalmers J. 1999 World Health Organisation International Society for Hypertension Guidelines for the Management of Hypertension: J Hypertens 1999; 17: 151-83.