Editor's Choice | This Week in BMJ | Press releases

BMJ No 7122 Volume 315 Letters Saturday 13 December 1997 Use of statins See Editorial by Muldoon p 1554 Sheffield tables have shortcomings Editor Since their publication the Sheffield tables(1) have been distributed to the medical profession by both the Consumers Association(2) and, more recently, the Standing Medical Advisory Committee.(3) Although we agree with the advisory committee that calculation of the absolute risk of coronary heart disease is an essential prerequisite for decisions on primary prevention, we have misgivings about the use of the Sheffield tables for this purpose. The tables are based on data correlating the absolute risk of coronary heart disease with the risk factor status of individuals in the Framingham study; however, they have been simplified by excluding variation in high density lipoprotein cholesterol from the analysis and dichotomising blood pressure into normotensive or hypertensive. We believe that these simplifications could lead to major errors in the estimate of absolute risk. This is of particular concern when estimating risk in patients with non-insulin dependent diabetes, whose high density lipoprotein cholesterol is often low. Another concern is that the tables militate against the measurement of serum cholesterol in younger people without non-lipid risk factors, 1 in 500 of whom have familial hypercholesterolaemia, which is associated with a nearly 50-fold increase in the risk of death from coronary heart disease between the ages of 20 and 39 (A Neil, personal communication). In contrast they promote treatment with lipid lowering drugs for elderly people despite the paucity of evidence of benefit from such intervention in asymptomatic people aged over 65. Thus 70 year old male smokers are considered eligible for statin treatment if their serum cholesterol is 5.5 mmol/l, which seems inappropriate on both scientific and financial grounds. We consider that calculation of absolute risk is best done by using the full Framingham risk score,(4) which is available in a mmol/l version on a computer disk, free of charge. We also advocate calculating the relative risk of coronary heart disease as well as the absolute risk and suggest that below the age of 65 a relative risk of 4 and over may require action whereas above that age the value should be 2 and over before treatment is considered, whatever the absolute risk. As regards which level of absolute risk should determine eligibility for treatment, we tend to favour a risk of 20% over 10 years, as advocated by the European Societies of Cardiology and Hypertension and the European Atherosclerosis Society,(5) rather than the 30% risk advocated by the Standing Medical Advisory Committee.(3) The latter value can be justified only on the grounds of treatment costs, which will decrease considerably when statins can be manufactured generically. John Betteridge Chairman, British Hyperlipidaemia Association Department of Medicine, Middlesex Hospital, London W1N 8AA James Shepherd Past chairman, European Atherosclerosis Society Department of Pathological Biochemistry, Royal Infirmary, Glasgow G4 0SF Gilbert Thompson Chairman, British Atherosclerosis Society MRC Lipoprotein Team, Hammersmith Hospital, London W12 0HS References 1 Haq I Q, Jackson P R, Yeo W W, Ramsay L E. Sheffield risk and treatment table for cholesterol lowering for primary prevention of coronary heart disease. Lancet 1995;346:1467-71. 2 Management of hyperlipidaemia. Drug Ther Bull 1996;34(suppl):89-93. 3 NHS Executive. SMAC statement on use of statins. Wetherby, West Yorkshire: Department of Health, 1997. (Executive letter EL(97)41.) 4 Anderson K M, Wilson P W F, Odell P M, Kannel W B. An updated coronary risk profile. A statement for health professionals. Circulation 1991;83:356-62. 5 Pyörölä K, de Backer G, Graham I, Poole-Wilson P, Wood D on behalf of the task force. Prevention of coronary heart disease in clinical practice: recommendations of the Task Force of the European Society of Cardiology, European Atherosclerosis Society, and European Society of Hypertension. Eur Heart J 1994;15:1300-31. Home | Current issue | Past issues | Classified ads | Career Focus | Feedback Collections | About this site | About the BMJ | BMA | Medline