To investigate whether general practitioners (GPs) in countries with different levels of cardiovascular risk would make different risk estimates and choices about lipid-lowering treatment when assessing the same patients.

Primary prevention of coronary heart disease should be based on the quantitative assessment of an individual’s absolute risk. Risk-scoring charts have been developed, but in clinical practice risk estimates are often made on a subjective basis.

Mail survey: Nine written case simulations of four cases rated by the Framingham equations as high risk, and five rated as low-risk were mailed to 90 randomly selected GPs in Stockholm, as a high-risk area, and 90 in Sicily as a low-risk area. GPs were asked to estimate the 10-year coronary risk and to decide whether to start a lipid-lowering drug treatment.

Overall risk estimate was lower in Stockholm than in Sicily for both high-risk cases (median 20.8; interquartile range (IQR) 13.5–30.0 versus 29.1; IQR 21.8–30.6; P = 0.033) and low-risk cases (6.4; IQR 2.2–9.6 versus 8.5; IQR 6.0–14.5; P = 0.006). Swedish GPs were less likely than Sicilian GPs to choose to treat when their estimate of risk was above the recommended cut-off limit for treatment, both for the entire group (means of GPs’ decision proportions: 0.64 (0.45) and 0.92 (0.24), respectively, P = 0.001) and for high-risk cases (0.65 (0.45) and 0.93 (0.23), P = 0.001).

The cardiovascular risk level in the general population influences GPs’ evaluations of risk and subsequent decisions to start treatment. GPs’ risk estimates seem to be inversely related to the general population risk level, and may lead to inappropriate over- or under-treatment of patients.