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Prevalence: hypertension
Purpose:
To ascertain the prevalence of hypertension from General Practice records and help ensure high standards of
primary health care and treatment delivered to NHS patients.
Hypertension is a common medical condition which is largely managed in primary care. Trials of anti-hypertensive
treatment have confirmed a significant reduction in the incidence of stroke and coronary heart disease in patients
with treated and controlled hypertension.
Definition of indicator and its variants:
Proportion of patients with established hypertension in a GP registered population. The British Hypertension
Society recommends that drug therapy should be started in all patients with sustained systolic blood pressures of
greater than or equal to 160 mmHg or sustained diastolic blood pressures of greater than or equal to 100 mmHg
despite non-pharmacological measures.
Statistic
Sex
Age
group
Organisation
(see glossary)
Number and percent of
patients
P
All Ages
E, GOR, SHA,
PCO
Period
Current
data
FY 2009/10
File_worksheet Name
Trend data
08F_618PC_10_V1
Numerator:
Numerator data - Patients registered with GP practices with a coded diagnosis of established hypertension.
Source of numerator data - Quality and Outcomes Framework (QOF).
Comments on numerator data - The data for this primary care indicator are derived from the Quality Management
Analysis System (QMAS) and supplied by the Prescribing Support Unit at The NHS Information Centre for health
and social care. The QOF is part of the General Medical Services (GMS) contract, with a focus on prevalence and
management of common chronic diseases at general practice level. It is aimed at measuring the achievement of
general practices against a set of evidence based negotiated standards and encouraging good practice.
The data to support the clinical quality indicators (i.e. clinical achievement data) are extracted from individual GP
practice clinical systems and sent automatically to QMAS once a month. Practices can make additional
submissions of clinical data at any time. A number of patirnts may be wrongly coded in this group, for example
patients who have had one-off high blood pressure readings or women who have been hypertensive in pregnancy.
Denominator:
Denominator data - All patients registered with GP practices (total practice list size).
Source of denominator data - See “Numerator data”.
Comments on denominator data - The practice list sizes are supplied to QMAS from the National Health
Applications and Infrastructure Services (NHAIS).
Statistical methods:
The data are presented as raw (unadjusted) figures as recorded by the practices. Ideally, comparisons between
PCOs should take into account differences between their populations in terms of age, gender and case-mix.
However, this is not possible at present as the supplied data are not broken down by these characteristics.
Please note that the prevalence data published for this indicator underestimate the level of hypertension morbidity
as compared with the findings from the Health Survey for England, a result of using wider range of denominator
population. The Health Survey uses as a denominator only those who had blood pressure measurement.
Interpretation of indicators:
Quality of indicator - Users of data derived from QMAS should recognise that QMAS was established as a
mechanism to support the calculation of practice QOF payments and not as a person based epidemiological tool.
It is not a comprehensive source of data on quality of care in general practice, but it is potentially a rich and
valuable source of such information, providing that the limitations of the data are acknowledged.
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