EDITOR—Unwin et al highlight the fact that several widely available guidelines for the management of hyperlipidaemia give conflicting advice for the primary prevention of cardiovascular disease.1 Some of the issues deserve further scrutiny.

The New Zealand guidelines are based entirely on the ratio of total to high density lipoprotein cholesterol concentrations for calculation of the absolute risk of cardiovascular disease over five years.2 The American national cholesterol education program, however, clearly says that it does not recommend use of the ratio of either total or low density lipoprotein cholesterol to high density lipoprotein cholesterol3; instead it recommends use of the absolute high and low density lipoprotein cholesterol concentrations. The rationale behind this is that these concentrations are independent risk factors with different determinants; combining …