Performance of the revised World Health Organization cardiovascular disease risk prediction models for the Middle East and North Africa: a validation study in the Tehran Lipid and Glucose Study.

OBJECTIVES

We aimed to evaluate the performance of the revised World Health Organization (WHO) models in predicting the 10-year risk of cardiovascular disease (CVD) in Iran, as part of the Middle East and North Africa (MENA) region.

STUDY DESIGN AND

SETTING

We analyzed data from the Tehran Lipid and Glucose Study (TLGS), including 5162 participants (2241 men) aged 40-80 years without CVD at baseline (the third examination, 2006-2008), for the occurrence of CVD (myocardial infarction (MI), coronary heart disease (CHD) death, and stroke). We assessed the statistical performance of original and regionally recalibrated models, both laboratory- and non-laboratory-based, using discrimination (C-statistic) calibration (calibration plot and observed-to-expected[O:E] ratio) and clinical performance applying net benefit (NB), a measure of true positives (TP) penalized for a weight of false positives (FP), a decimal value representing the expected proportion of TP outcomes among total population.

RESULTS

During the 10-year follow-up, 307 CVD events occurred. The cumulative incidence of CVD was 9.0% (95% CI: 8.0%-10.0%) in men and 4.0% (3.0%-5.0%) in women. For the laboratory-based model, the C-statistic was 0.72 (0.68-0.75) in men and 0.83 (0.80-0.86) in women; for the nonlaboratory-based model, it was 0.70 (0.66-0.73) and 0.82 (0.79-0.86) for men and women, respectively. The lab model underpredicted the risk (O:E = 1.20 [1.00-1.33] for men and 1.40 [1.13-1.60] for women). At the risk threshold of 10%, NB for the lab model was 0.03 (0.02-0.04) for men and 0.01 (0.004-0.01) for women; these values became zero or negative for thresholds over 20%. Regionally recalibrated models overestimated the risk (O:E < 1) and showed lower NB.

CONCLUSION

The loss of specificity was not sufficiently offset by the increase in sensitivity provided by the regionally recalibrated models compared to the original models.

PLAIN LANGUAGE SUMMARY: In this study, we assessed the performance of the World Health Organization (WHO) cardiovascular disease (CVD) risk models in Iran, which is part of the Middle East and North Africa (MENA) region. Regarding the statistical performance of the models, both the original and regionally recalibrated WHO models had good discriminative ability. Concerning calibration, another component of statistical performance, the original models underestimated the actual risk, while the recalibrated version overestimated it. Regarding the clinical performance of the models, both the original and regionally recalibrated versions were clinically useful at the risk threshold of 10%.