- Hypertension is defined as systolic BP over 140mmHg and/or diastolic BP over 90mmHg.
- Hypertension is the most common treatable risk factor for cardiovascular disease in the over-50s.
- More than one quarter of the world's adult population had hypertension in 2000. This is predicted to increase to 29 per cent by 2025 (Lancet 2005; 365: 217).
- BP targets are being lowered by newer guidelines, which can make them harder to reach.
What is the evidence?
- It is still unclear whether the benefits of specific antihypertensive drugs come from their direct effects on raised BP or whether they act by various other multiple indirect actions.
- The antihypertensive and lipid lowering to prevent heart attack trial (ALLHAT) found that thiazide-type diuretics reduce cardiovascular events as much as ACE inhibitors and calcium channel blockers in hypertensive patients (JAMA 2002; 288: 2,981-97).
- In the ASCOT study, 19,257 patients were randomised to one of two antihypertensive regimens. Patients in the amlodipine/perindopril group had a significant relative risk reduction in all-cause mortality, all major cardiovascular end points and also new-onset diabetes (Lancet 2005; 366: 895). The study was stopped early in view of these results.
- A meta-analysis has found that beta-blockers do not protect people from stroke as well as other alternatives (Lancet 2005; 366: 1,545).
Implications for practice
- The revised British Hypertension Society (BHS) guidelines recommend ACE inhibitors as first-line in all younger patients under 55 years, and thiazides or calcium-channel blockers in patients aged 55 years or more.
- NICE has just downgraded the role of beta-blockers in hypertension in its latest guidance following the ASCOT trial.
- It is generally accepted best practice to choose therapeutic agents which are likely to do more good than harm given each patient's social circumstances, preferences, coexisting medical conditions and risk factors.
This is also likely to improve compliance.
- Only a third of patients prescribed antihypertensives and lipid-lowering therapy are still taking both after six months, a recent study found (Arch Intern Med 2005; 165: 1,147).
- BHS guidelines
- NICE guidelines
www.hyp.ac.uk/bhs - British Hypertension Society
www.nice.org.uk - NICE
- Dr Louise Newson is a GP in the West Midlands and author of 'Hot Topics for MRCGP and General Practitioners', Pas Test 2006
- Hypertension is still under-diagnosed and under-treated.
- The type of drug is probably less important than the actual BP control.
- Compliance with antihypertensive medication is poor.
- NICE guidelines have just been reviewed.
- BP targets are being lowered by newer guidelines.