Comparison of current guidelines for the treatment of hypercholesterolaemia in secondary prevention: can the Swiss recommendations be simplified?

Objectives: Different guidelines exist for the treatment of hypercholestero laemia in patients with established coronary heart disease. We compared the requirement for drug treatment based on the NCEP II(U.S.), British, Europe an, and GSLA (Swiss) guidelines and examined the impact of a simplification of the current SWISS guidelines. Methods: Retrospective analysis of the lipid profiles of 2483 patients admi tted to our hospital between 1996 and 1997 with the diagnosis of coronary h eart disease. A prospective study analysing the lipid profiles, cardiovascu lar risk factors and drug treatment of 401 patients consecutively admitted to our hospital for an acute coronary event in 1999 was also performed. Results: According to the European recommendations, 76% of the retrospectiv ely studied patients qualified for drug treatment while the Swiss guideline s would treat 70% of all patients. Similarly, 72% and 60% of the prospectiv ely studied patients without prior statin treatment qualified for a drug tr eatment according to the European and Swiss guidelines respectively. A simp lification of the Swiss recommendations (LDL cholesterol [LDL-C] greater th an or equal to 3 mmol/l as the only criterion) would result in a concordant treatment decision relative to the current guidelines in 95% and 89% of th e patients in the retrospective and prospective studies respectively. Such a modification would lead to a slight increase in the percentage of patient s qualifying for drug treatment (+3% in the retrospective and +9% in the pr ospective study). In addition, the overall concordance with the European gu idelines would increase to 96% in the retrospective and prospective study p opulations. Finally, we also examined the impact of the absolute cut-off va lue of LDL-C on the number of patients requiring medical treatment. This an alysis revealed a 5-10% increase in the number of patients qualifying for t reatment per 0.2 mmol/l decrease in the cut-off value for LDL-C, with the e xception of a 20% increase between 3.4 and 3.2 mmol/l. Conclusions: Although guidelines vary in the percentage of patients qualify ing for drug treatment of hypercholesterolaemia, their overall concordance is approximately 90%, with the Swiss recommendations being more conservativ e than the European guidelines. Given the high degree of concordance betwee n the Swiss and most other guidelines, which are based on a simpler decisio nal algorithm, we propose that the Swiss guidelines be simplified by measur ing only a single parameter, e.g. an LDL-cholesterol threshold value of gre ater than or equal to 3 mmol/l. This simplification would hopefully enhance the acceptance and clinical use of such guidelines in the medical communit y.