Validation of the Pooled Cohort equations in a long-term cohort study of Hong Kong Chinese

Background: The 2013 American College of Cardiology and the American Heart Association guidelines recommended the Pooled Cohort equations for evaluation of cardiovascular (CV) risk of individuals.

Objective: We investigated the usefulness of the Pooled Cohort equations in Chinese by validating this risk prediction model using the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS) cohort.

Methods: The Hong Kong CRISPS is a population-based prospective cohort study of CV risk factors among 2895 Chinese men and women (aged 25-74 years) initiated in 1995. CV events were ascertained until December 2012. The discrimination and calibration of the Pooled Cohort equations were evaluated and compared with the Framingham CV risk equation. A Hosmer-Lemeshow chi-square statistic (X(2)) of <20 indicated good calibration.

Results: The discrimination power of the 2 models in both men and women was moderate. The calibration score of both models were unacceptable in men (Pooled Cohort X(2), 24.1; Framingham X(2), 20.1), but was satisfactory in women (10.1 and 12.1, respectively). In men, with recalibration of the model using the CRISPS data, the accuracy of prediction improved. Recalibration, however, could not be applied to the Pooled Cohort model because the degree of miscalibration varied across the different risk categories.

Conclusions: The Pooled Cohort equations provide poor calibration and moderate discrimination in Hong Kong Chinese, especially in men. In contrast, the Framingham CV risk equation can be applied to the Chinese population but requires recalibration in men.