Extract from theCompendium of Clinical and Health Indicators User Guide
NHS Information Centre for health and social care
Antiplatelet / anti-coagulant therapy for patients with coronary heart disease Purpose:
To help reduce the level of risk to health for NHS patients with coronary heart disease (CHD) and ensure high standards of primary health care and treatment delivered to them. Aspirin should be given routinely and continued for life in all patients with CHD unless there is a contraindication. Clopidogrel is an effective alternative in patients with contraindications to aspirin, or who are intolerant of aspirin. Aspirin should be avoided in patients who are anticoagulated.
Definition of indicator and its variants:
Proportion of patients on the CHD register with a record in the last 15 months that aspirin, an alternative anti-platelet therapy, or an anti-coagulant is being taken, unless contraindications or side-effects are recorded.
Statistic Organisation File_worksheet Name (see glossary) Trend data Numerator:
Numerator data - Patients on the CHD register who have a record that aspirin, an alternative anti-platelet therapy, or an anti-coagulant is being taken in the 15 months before the reference date, unless contraindications or side-effects are recorded. 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. The ‘reference date’ is the specified date of patient records held by the general practice modelled for the end of the QOF year (midnight 31st March). It is the same for the data from all practices and may differ from the date of data submission. Denominator:
Denominator data - All patients on the CHD register excluding those who have been exception reported. Patients may be exception reported for the following reasons:
registered in the three months before the reference date;
CHD exception reported in the 15 months before the reference date;
ischaemic heart disease diagnosis recorded in the three months before the reference date;
persistent and expiring salicylate contraindications recorded;
persistent and expiring warfarin contraindications recorded;
persistent and expiring clopidogrel contraindications recorded.
For more details regarding the description of the selection criteria and dataset rules of the relevant indicator set see the following documentation available at:
Source of denominator data - See “Numerator data”.
Extract from theCompendium of Clinical and Health Indicators User Guide
NHS Information Centre for health and social care
Comments on denominator data - The denominator is a count of patients for whom the clinical indicator should be met. However, the selection rules do not provide the same opportunity for all patients included in the denominator to take advantage of the full period (maximum number of months after the diagnosis) allowed by good practice for the test, measurement or treatment to be undertaken (e.g. if good practice for angina patients allows for a particular test to be conducted up to 12 months after diagnosis then patients diagnosed between four and 11 months before the reference date do not have the full period of 12 months for the test). Additionally, patients can be removed from the denominator through the application of exception reporting.
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.
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 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.
There have been some significant revisions to the QOF, compared to previous years. Therefore direct comparisons cannot be made except for the indicators that have not been subject to definitional changes.
Further reading:
1. The NHS Information Centre for health and social care. National Quality and Outcomes Framework Achievement Data 2009/10, October 2010. Availabl
2. NHS Employers and BMA. Quality and Outcomes Framework guidance for GMS contract 2009/10, March 2010.
3. The NHS Information Centre for health and social care. National Quality and Outcomes Framework Achievement Data 2008/09, September 2009. Available a
4. NHS Employers and General Practitioners Committee BMA. Quality and Outcomes Framework guidance for GMS contract 2008/09, April 2008. Available at:
5. The NHS Information Centre for health and social care. National Quality and Outcomes Framework Statistics for
6. The Information Centre for health and social care, Prescribing Support Unit. National Quality and Outcomes Framework Statistics for England 2006/07. Available at:
7. The Information Centre for health and social care, Prescribing Support Unit. National Quality and Outcomes Framework or England 2005/06. Available at:
8. The Health and Social Care Information Centre, NationalQuality and Outcomes Framework Statistics for England
9. Ashworth M, Armstrong D. The relationship between general practice characteristics and quality of care: a
national survey of quality indicators used in the UK Quality and Outcomes Framework, 2004-5, BMC Family Practice, London: Ashworth and Armstrong, 2006 7:68. Available at:
10. Department of Health, Investing in General Practice. The New General Medical Services Contract. Available at:
11. Eastern Region Public Health Observatory, The limitations of Quality and Outcomes Framework (QOF) data.
Updated: June 2011
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ON TRIPLE FACTORISATIONS OF FINITE GROUPSSchool of Mathematics and Statistics, The University of Western Australia, Crawley WA 6009, AUSTRALIAThe second criterion characterises triple factorisations of G in terms of a subset of ΩB havingLet G, Ω, ∆ and be as in Notation 1. Then the Embedding Theorem for imprimitive permutationrestricted movement. For a finite subset Γ of Ω, the mo
Extract from theCompendium of Clinical and Health Indicators User Guide
NHS Information Centre for health and social care
Antiplatelet / anti-coagulant therapy for patients with coronary heart disease 
Extract from theCompendium of Clinical and Health Indicators User Guide
NHS Information Centre for health and social care
Comments on denominator data - The denominator is a count of patients for whom the clinical indicator should be met. However, the selection rules do not provide the same opportunity for all patients included in the denominator to take advantage of the full period (maximum number of months after the diagnosis) allowed by good practice for the test, measurement or treatment to be undertaken (e.g. if good practice for angina patients allows for a particular test to be conducted up to 12 months after diagnosis then patients diagnosed between four and 11 months before the reference date do not have the full period of 12 months for the test). Additionally, patients can be removed from the denominator through the application of exception reporting.