Primary prevention of cardiovascular disease: new guidelines, technologies and therapies

In reply: We thank Campbell and Aroney for their comments. Addressing Campbell’s concerns, risk categorisations are made to simplify stratification and communication of cardiovascular disease (CVD) risk. It is correct that the United States and Europe have a longer period and differing thresholds for action. A shorter period was selected in Australia due to patient preference for shorter-term over longer-term outcomes (ie, discounting).1 Categorisation arguments can similarly be made for the thresholds used for individual risk factors. The short-term approach can be thought of as best identifying those likely to have covert disease and to benefit from pharmacotherapy. The lifetime risk does not need to be ignored, as lifestyle interventions should still be recommended to reduce risk. The validation study cited by Campbell reports a c-statistic of 0.76 (95% CI, 0.71–0.81) — considerably better than a coin toss.2 “Simply repeating blood pressure and lipid level measurements” did not significantly alter this figure. Numerals entered in a risk calculator have the same standards for measurement as for individual risk factors. Reclassification is less likely for an absolute risk approach than an individual risk factor approach, as it is tempered by other measures.