Equalisation of four cardiovascular risk algorithms after systematic re-calibration: individual-participant meta-analysis of 86 prospective studies
Aims There is debate about the optimum algorithm for cardiovascular disease (CVD) risk estimation. We conducted head-to-head comparisons of four algorithms recommended by primary prevention guidelines, before and after “re-calibration”, a method that adapts risk algorithms to take account of differences in the risk characteristics of the populations being studied. Methods and Results Using individual-participant data on 360,737 participants without CVD at baseline in 86 prospective studies from 22 countries, we compared the Framingham Risk Score (FRS), Systematic Coronary Risk Evaluation (SCORE), Pooled Cohort Equations (PCE), and Reynolds Risk Score (RRS). We calculated measures of risk discrimination and calibration, and modelled clinical implications of initiating statin therapy in people judged to be at “high” 10-year CVD risk. Original risk algorithms were re-calibrated using the risk factor profile and CVD incidence of target populations. The four algorithms had similar risk discrimination. Before re-calibration, FRS, SCORE and PCE over-predicted CVD risk on average by 10%, 52%, and 41%, respectively, while RRS under-predicted by 10%. Original versions of algorithms classified 29-39% of individuals aged ≥40 years as high-risk. By contrast, re-calibration reduced this proportion to 22-24% for every algorithm. We estimated that to prevent one CVD event, it would be necessary to initiate statin therapy in 44-51 such individuals using original algorithms, in contrast to 37-39 individuals with re-calibrated algorithms. Conclusion Before re-calibration, the clinical performance of four widely used CVD risk algorithms varied substantially. By contrast, simple re-calibration nearly equalised their performance and improved modelled targeting of preventive action to clinical need.