Method: 144 currently practising GPs were recruited at 4 General Practice conferences in Australia. GPs completed a paper-based survey consisting of patient cases in which absolute risk and three key indicators related to absolute CVD risk (blood pressure, cholesterol and age) were varied.
Result: For patient cases in which the levels of absolute risk and individual risk factors were inconsistent, GPs seemed more likely to base their treatment decision on individual risk factors than absolute risk. More specifically, GPs were less likely to prescribe medication for high absolute risk (i.e. >15% risk of a cardiovascular event over the next 5 years, the treatment threshold in Australia) if the case presented a patient with lower blood pressure in comparison with high blood pressure (4% vs 93%, p<0.001). In addition, GPs were more likely to prescribe blood pressure lowering medication for low or moderate absolute risk (<10%) if the patient case had high blood pressure in comparison with lower blood pressure (79% vs 0%, p<0.001). This pattern was less pronounced for cholesterol lowering drugs. There were no differences in the way GPs prescribed for patient cases ranging in ages from 45 to 72 years at similar risk. However, GPs prescribed less medication for patients aged 86 years compared to those aged 72 (e.g. cholesterol lowering drugs: 29% vs. 49%, p<0.001). GP characteristics (gender, age, years in practice, practice size, stated use of absolute risk) did not predict their pattern of prescribing.
Conclusion: GPs seem more likely to base their CVD treatment decision making on individual risk factors than absolute risk. This effect seems to be stronger for blood pressure lowering medication compared to cholesterol lowering drugs.