Four papers in this week’s BMJ address the issue of preventing heart disease, and in particular using lipid lowering drugs, in primary care. Several major guidelines have been developed for the screening and management of patients with hypercholesterolaemia and other lipid disorders, but the advice incorporated in them often differs considerably. Unwin et al (p 1125) examined the implications of four widely available guidelines by applying them to data from a population based survey of adults and found marked differences between the guidelines in the numbers who would be screened and treated. Even when the proportions who would be treated were similar the individuals were often different. These findings highlight the pressing need to develop and agree a consistent approach across Britain to the management of hyperlipidaemia.
Strategies such as guideline development and critical appraisal are intended to facilitate everyday practice based on trial evidence. But these strategies may be based on unrealistic models of how evidence is assessed and used. Fairhurst and Huby report that prescribing of statin drugs general practitioners have not conventionally critically appraised trials but have evaluated their social and economic implications. Recognition of a consensus among trusted sources about these implications is important in facilitating integration of trial evidence in practice.
On p 1120 Pringle describes how one practice attempted to integrate data from clinical audit, trials, guidelines, and cost effectiveness analyses to improve its care of patients with heart disease. Prompted by the case of a 52 year old man who died of an acute myocardial infarction the practice assessed how well it was recording risk factors, reviewed the literature on hyperlipidaemia, and revised its protocol for managing hyperlipidaemia. The new protocol involved extra consultations, cholesterol tests, and drug costs.
As a result they showed a 30-fold rise in the number of patients diagnosed as having hyperlipidaemia (from 13 to 389): 46% were receiving lipid lowering drugs. Stories such as Pringle’s may help to explain the finding of Baxter et al (p 1134) that prescribing of lipid lowering drugs in one English region showed a 98-fold variation between practices. Even so, prescribing of lipid lowering drugs had increased exponentially since 1994 in the four health authorities studied.