Hypertension is a major modifiable risk factor for cardiovascular disease (CVD). It is a particular risk for stroke and myocardial infarction, but also for heart failure, chronic kidney disease, cognitive decline and premature death. In 2010, it was estimated that hypertension causes between 10 and 11 per cent of all UK deaths.¹ A study published recently in the Lancet found that a patient aged 30 years with hypertension has a lifetime risk of CVD of 63 per cent and develops it five years earlier than someone with normal blood pressure (BP).²

In most cases, there is no identifiable cause, but in a small number, the hypertension is secondary to other diseases. Untreated hypertension is usually associated with a progressive rise in BP. The vascular and renal damage that this may cause can culminate in a treatment-resistant state. The risk associated with increasing blood pressure is continuous, with each 2mmHg rise in systolic blood pressure associated with a seven per cent increased risk of mortality from ischaemic heart disease and a 10 per cent increased risk of mortality from stroke. Prevalence of hypertension is strongly influenced by age, and increasing age is associated with a rise in systolic blood pressure (as a result of progressive stiffening and loss of compliance of larger arteries), while diastolic blood pressure increases up to about the age of 60 years, plateaus and then falls.

At least one quarter of adults (and more than half of those older than 60) have high blood pressure and thus the clinical management of hypertension is one of the most common interventions in primary care. Blood pressure is variable and can be affected by time of day, posture, emotions, exercise, meals, certain drugs, bladder fullness, pain, shock, dehydration and acute changes in temperature. Given these variables, diagnosing hypertension based on individual clinic measurements can be problematic and one of the biggest changes in the NICE Hypertension Guideline 2011³ was that a diagnosis of primary hypertension should be confirmed using 24-hour ambulatory blood pressure monitoring (ABPM) as gold standard. When interpreting the results of ABPM, it should be remembered that average daytime blood pressure values are approximately 10/5mmHg lower than clinic measurements.

The Guideline also gives a framework for use of home blood pressure monitoring. For the first time, this change empowers patients to become more involved in the monitoring and care of their hypertension, although validated BP monitors as recommended by the British Hypertension Society⁴ should be used.