The 'lottery' of cardiovascular risk estimation with Internet-based risk calculators

The cardiovascular disease (CVD) is the leading cause of disability and premature death around the world. The ongoing publication of systematic and critical literature reviews has contributed to generate a kaleidoscope of guidelines by different scientific organizations. We investigated the accordance among the most popular web-based CVD risk calculators on the Internet. We carried out a simple study, by estimating the risk of CVD using the most popular Internet-based calculators available on the Internet. A Google search was performed, using the keyword "cardiovascular risk calculator", to identify the first 10 websites providing free on-line CVD risk calculators. We arbitrarily selected the cardiovascular profile of two subjects of a typical Western family: a 55-year man at a likely intermediate cardiovascular risk and a 45-year woman at a probable low risk. The score calculated according to the two arbitrary CVD risk profiles, one of whom was supposed to be at intermediate risk and the other at lower risk, was extremely variable. More specifically, the 10-year CVD risk of the 55-year old man varied from 3% to over 25% (median value, 12.9%, interquartile range [IQR], 10.7-19.0%), whereas that of the 45-year women varied between 0% and 4% (median value, 1.2%; IQR, 0.4-2.2%), thus displaying a nearly 10-fold variation in both cases. We concluded from our analysis of 11 different Internet-based CVD risk calculators that the final 10-year risk score can be extremely different, especially for the 55-year old man at predictably intermediate risk.