Development of a risk equation for the incidence of coronary artery disease and ischemic stroke for middle-aged Japanese – Japan public health center-based prospective study

Background:Global risk assessment for the prevention of atherosclerotic cardiovascular diseases helps guide the intensity of behavioral and pharmacological interventions.Methods and Results:The Japan Public Health Center-based prospective (JPHC) Study Cohort II (age range: 40–69 years at baseline in 1993–1994, n=15,672) was used to derive the risk equations for coronary artery disease (CAD) and ischemic stroke incidence via hazard regression. The model discrimination was evaluated by the area under the receiver-operating curve (AUC), and model goodness-of-fit by the Grønnesby-Borgan chi-squared statistic. During a mean of 16.4 years of follow up, 192 incident CAD cases and 552 ischemic stroke cases occurred. Variables selected for the CAD equation were age, sex, current smoking, systolic blood pressure, antihypertensive medication use, diabetes, and high-density lipoprotein cholesterol (HDLC) and non-HDLC. The same variables, except non-HDLC, were selected for the ischemic stroke equation. The equations discriminated incidence reasonably well (AUC: 0.81 for CAD, 0.78 for ischemic stroke). The AUC of the equation applied externally to Cohort I (n=11,598) was also good: 0.77 and 0.76 for CAD and ischemic stroke, respectively. Risk calculator application and color charts to visualize estimated risk according to the combinations of risk factors were prepared.Conclusions:Risk equations were developed to estimate the 10-year probability of CAD and ischemic stroke in Japanese people, using variables that are routinely obtained.