Objective: To examine the existing Framingham Risk Score (FRS) and Chinese Risk Score (CRS) in predicting the development of ischemic cardiovascular diseases (ICVD), and determine potential added value of novel risk factors.
Methods: The China Multi-Provincial Cohort Study (CMCS) was a population-based prospective cohort study in 11 provinces of China. An annual follow up was conducted in 840 men aged 35 to 64 years in Shanghai cohort, who were without coronary heart disease and stroke at baseline examination in 1992, to collect the incidence data of ICVD events (coronary death, myocardial infarction, and ischemic stroke). The detection of novel risk factors were conducted for the cohort in 2007. The basic Framingham and Chinese prediction scores power were assessed by using C-statistic of ICVD events associated with risk scores, then the novel risk factors were evaluated by adding them independently to the basic Chinese models. The area under the curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement(IDI) were calculated to determine if each of the novel risk factors improved risk prediction.
Results: By the end of December 2014, 24 cases of coronary heart disease (myocardial infarction or/and coronary death), 45 cases of ischemic stroke had occurred in 840 subjects in Shanghai cohort with a follow-up of 22.3 years averagely. Both the FRS and CRS had predicting power for ICVD, the AUCs were 0.6576 (95%CI: 0.5942-0.7240) and 0.7265 (95%CI: 0.6643-0.7887), respectively. The incremental AUC was 0.0689 (95%CI: 0.0196-0.1171) (P=0.006). None of the novel risk factors significantly improved the AUC. High-sensitive-CRP (hs-CRP) was the only novel risk factor resulting in a significant increase of NRI. CRS in 2007 significantly improved the IDI, but net changes were small.
Conclusions: CRS had high power in the 20-year risk prediction for ICVD in middle-aged men in Shanghai. The inclusion of hs-CRP could make some improvement in risk prediction, but is unlikely to be meaningful when reclassification or new discrimination strategy are made which can change the clinical risk.