External validation and clinical usefulness of three commonly used cardiovascular risk prediction scores in an Emirati population: a retrospective longitudinal cohort study

Abstract

Objectives: Cardiovascular disease (CVD) risk prediction models are useful tools for identifying those at high risk of cardiovascular events in a population. No studies have evaluated the performance of such risk models in an Arab population. Therefore, in this study, the accuracy and clinical usefulness of two commonly used Framingham-based risk models and the 2013 Pooled Cohort Risk Equation (PCE) were assessed in a United Arab Emirates (UAE) national population.

Design: A 10-year retrospective cohort study.

Setting: Outpatient clinics at a tertiary care hospital, Al-Ain, UAE.

Participants: The study cohort included 1041 UAE nationals aged 30-79 who had no history of CVD at baseline. Patients were followed until 31 December 2019. Eligible patients were grouped into the PCE and the Framingham validation cohorts.

Exposure: The 10-year predicted risk for CVD for each patient was calculated using the 2008 Framingham risk model, the 2008 office-based Framingham risk model, and the 2013 PCE model.

Primary outcome measure: The discrimination, calibration and clinical usefulness of the three models for predicting 10-year cardiovascular risk were assessed.

Results: In women, the 2013 PCE model showed marginally better discrimination (C-statistic: 0.77) than the 2008 Framingham models (C-statistic: 0.74-0.75), whereas all three models showed moderate discrimination in men (C-statistic: 0.69‒0.70). All three models overestimated CVD risk in both men and women, with higher levels of predicted risk. The 2008 Framingham risk model (high-risk threshold of 20%) classified only 46% of women who subsequently developed incident CVD within 10 years as high risk. The 2013 PCE risk model (high-risk threshold of 7.5%) classified 74% of men who did not develop a cardiovascular event as high risk.

Conclusions: None of the three models is accurate for predicting cardiovascular risk in UAE nationals. The performance of the models could potentially be improved by recalibration.

Keywords: cardiovascular disease; framingham; pooled cohort equation; risk prediction; united arab emirates; validation.

Conflict of interest statement

Competing interests: None declared.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Flow chart of patients included in the study. ASCVD, atherosclerotic cardiovascular disease; CVD, cardiovascular disease; PCE, Pooled Cohort Risk Equation.

Figure 2

Calibration plots of observed and predicted 10-year cardiovascular disease risks using the 2008 Framingham (green), 2008 office-based Framingham (red), and PCE (black) risk prediction models in Emirati men and women. PCE, Pooled Cohort Risk Equation.