Letters

National service framework for coronary heart disease

Ambiguities need to be clarified

Target of lowering cholesterol by 30% needs to be justified

Many operators and facilities will not meet standards set out in framework

Ambiguities need to be clarified

EDITOROne of the priorities in the national service framework for coronary heart disease summarised by Mayor¹ was "improved use of effective medicines after heart attackespecially aspirin,  blockers, and statinsso that 80-90% of people discharged from hospital after a heart attack will be prescribed these drugs." This is the recommendation in the executive summary, which taken at face value implies that all three drugs should be prescribed before a patient leaves hospital. In contrast, the recommendation in the main document is that aspirin and  blocker treatment should be started in hospital and statin treatment left for "continuing care."

Statin treatment was not started at the time of infarction in any of the large secondary prevention studies. The shortest times from infarction to inclusion were six months in the Scandinavian simvastatin survival study (4S),² and three months in the cholesterol and recurrent events (CARE) study³ and the long term intervention with pravastatin in ischaemic disease (LIPID) study.⁴ Thus the common practice of starting treatment before discharge is not strictly evidence based and statin treatment may be harmful immediately after myocardial infarction. Starting treatment before discharge, however, ensures that the drug is prescribed and simplifies audit.

A further recommendation in the main document is "give statins to lower serum cholesterol concentrations either to less than 5 mmol/l (low density lipoprotein cholesterol below 3 mmol/l) or by 30% (whichever is greater)." I find this ambiguous because a percentage change cannot be compared to a concentration, but I presume that the intention is to exclude from treatment those with a total cholesterol concentration under 5 mmol/l on admission. An audit of my own patients with myocardial infarction showed that statin treatment was not appropriate in 22% for this reason.

The main document states that patients with acute myocardial infarction should usually receive the recommended interventions unless contraindicated. Surely all patients without intolerance or contradindications should receive aspirin and  blockers. Similarly, all patients with a total cholesterol concentration greater than or equal to 5 mmol/l should be treated with a statin, but they may number less than 80% of the total. Whether the 80-90% standard above applies to all patients or to those without contraindications is not clear.

These ambiguities need to be clarified or the results of comparative audit will be meaningless. The criteria for audit should be as rigorous as those for clinical trials.

Roger Lloyd-Mostyn, consultant physician. 
King's Mill Centre, Sutton-in-Ashfield, Nottinghamshire NG17 4JL

Competing interests: Dr Lloyd-Mostyn has been reimbursed for attending conferences and speaking at meetings by companies that manufacture lipid lowering drugs.

Target of lowering cholesterol by 30% needs to be justified

EDITORThe target cholesterol concentration of the national service framework for coronary heart disease seems to be problematic,¹ which has important consequences for primary care. Most clinicians agree about the value of evidence based guidelines in preventing coronary heart disease and the need for clarity. But the recommendation to reduce cholesterol concentration by 30% is not based on evidence, and at worst seems to be arbitrary, thus weakening the document.

The issue of using cholesterol target concentrations or percentage reductions has been discussed,² and the consensus among recent guidelines is to aim for a target cholesterol concentration of less than 5.0 mmol/l. ^{3 4} The original guidance on the use of statins from the Standing Medical Advisory Committee in 1997 suggested a reduction in cholesterol concentration of 20-25% in line with the outcome trials, and the developers of the new Sheffield table⁵ suggest 25% (L E Ramsay, personal communication).

I am concerned that the national service framework's target of 30% will become a national audit standard that will be difficult to achieve, with adverse consequences for primary care. It would penalise good management, result in more visits and tests, and demoralise staff and patients. To achieve this target higher doses of statins might be used beyond the trial doses (40 mg), or most patients might be given atorvastatin (which does not have yet any trial evidence). Side effects may increase and the ratio of risk to benefit may shift. This has major implications as statins become more widely used in large populations. In the interests of fostering healthy debate, it would be helpful for the national service framework to justify the 30% figure.

Paul Cracknell, general practitioner. 
Killamarsh Medical Practice, Sheffield S21 4DJ paul.cracknell{at}virgin.net

Competing interests: None declared.

Many operators and facilities will not meet standards set out in framework

EDITORMayor's news item reported the publication of the national framework for coronary heart disease for England.¹ Section 2 of the framework focuses on improving the quality of care offered to patients with coronary heart disease.² It publishes standards that operators and facilities for interventional cardiological procedures are expected to achieve. Some of these standards address the annual number of cardiac catheterisations, coronary angioplasties, and coronary artery bypass operations that operators and facilities must achieve.

We used the hospital episode system database for the West Midlands for the most recent year available (1 April 1996 to 31 March 1997) for a study that we carried out. We calculated the proportion of facilities and consultant firms in the West Midlands providing services that complied with these new standards, and the proportion of patients treated by these facilities and consultant firms.

Data on the hospital episode system record the consultant firm, not the person doing the procedure, so we used the consultant firm as a proxy for the individual operator. The effect of this would be to overestimate the proportion of procedures done by "above threshold" operators. To reduce bias from coding errors we excluded consultants and trusts that undertook only one procedure during 1996-7 unless they had undertaken that procedure for three consecutive years.

The table shows the results. While 98% of patients had their coronary artery bypass grafting done in an above threshold facility by an above threshold consultant firm, the proportions for coronary angioplasty and cardiac catheterisation were only 73% and 71% respectively. We looked in more detail at cardiac catheterisations: of the 1780 patients treated in a below threshold facility, 1458 were operated on by an above threshold consultant firm. To comply with the national service framework's standards 10 facilities in the West Midlands would have to stop doing cardiac catheterisations (despite most patients being treated by cardiologists with an adequate caseload) or cases would have to be redistributed between hospitals.

These findings show that unless cardiac catheterisation and coronary angioplasty practices have changed since 1996-7, many operators and facilities will not meet the standards set out in the national service framework. We are aware that over the past few years many more patients have undergone coronary stenting and angioplasty, and the proportion of patients treated by individual cardiologists is therefore likely to have improved. This, however, needs to be established.

Kate Jolly, lecturer in public health and epidemiology. 
C.B.Jolly{at}bham.ac.uk

Andrew Rouse, senior lecturer in public health and epidemiology. 
University of Birmingham, Birmingham B15 2TT

Greg Y H Lip, reader in medicine. 
University Department of Medicine, City Hospital, Birmingham B18 7QH

Competing interests: None declared.