External Validation of Cardiovascular Risk Scores in the Southern Cone of Latin America: Which Predicts Better?

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Abstract

Background: Inaccurate estimates of demographic cardiovascular risk may lead to an inadequate management of preventive medical interventions such as the use of statins.

Objectives: The aim of this study was to evaluate the external validity of cardiovascular risk equations in the general population of the Southern Cone of Latin America.

Methods: Equations including variables evaluated in the CESCAS cohort study and that estimate overall cardiovascular
mortality (CUORE, Framingham, Globorisk and Pooled Cohort Studies) were assessed. For each equation, an independent
analysis was performed taking into account the cardiovascular events originally considered. Discrimination of each equation
was evaluated through C-statistic and Harrell’s C-index. To assess calibration, a graph was built for each equation with the
proportion of observed events vs. the proportion of estimated events by risk quintiles and the β slope of the resulting linear regression was calculated. Sensitivity and specificity were determined for the detection of people at high cardiovascular risk.

Results: The median follow-up time of the cohort at the time of the analysis was 2.2 years, with an interquartile range of 1.9
to 2.8 years. Sixty cardiovascular events were incorporated into the analysis. All C-statistic and Harrell’s-C index values were
greater than 0.7. The value of the β slope farthest from 1 was that of the Pooled Cohort Studies score.

Conclusions: Although the external validation parameters evaluated were similar, CUORE, Globorisk and the Framingham equations showed the best global performance for cardiovascular risk estimation in our population.