Validating the Framingham Hypertension Risk Score: A 4-year follow-up from the Brazilian Longitudinal Study of the Adult Health (ELSA-Brasil)

Abstract

The Framingham Heart Study published an equation that permits to estimate the 4-year incidence of hypertension among adults. In Brazil, only the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) of 15 105 men and women aged 35-74 years enrolled in 2008-2010 has data that can validate the Framingham Risk Score for Hypertension and create a new equation according to the Brazilian population. We examined the predictive performance of the Framingham Risk Score for Hypertension in the ELSA-Brasil using as an outcome variable, the 4-year incidence of hypertension. We split randomly the 8027 participants who participated in the second visit (2012-2014) and without hypertension at baseline in derivation data set (n = 4825; 60%) and a validation data set (n = 3202 participants; 40%). The area under the curve for Framingham Risk Score for Hypertension and ELSA-Brasil Risk Score was relatively similar. Hosmer-Lemeshow chi-squared statistic applied for the Framingham Risk Score was 3.78 (P-value = .876) and for our model was 8.22 (P-value = .41), disclosing good discrimination and calibration for both models. Even with these classification intervals, our model presents more underestimation of the risk, classifying 15% of the participants with new onset of hypertension in low risk vs 9% of the Framingham model and less overestimation of the risk, classifying 17% of the participants without hypertension as high risk vs 24% of the Framingham model. We concluded that the Framingham Risk Score for Hypertension has an acceptable performance when applied in the ELSA-Brasil population with good discrimination and calibration.