Validation of a risk prediction tool for coronary heart disease in middle-aged women

Background: Health risk appraisal tools may be useful for identifying individuals who would benefit from lifestyle changes and increased surveillance. We evaluated the validity of the Your Disease Risk tool (YDR) for estimating relative risk of coronary heart disease (CHD) among middle-aged women. Methods: We included 55,802 women in the Nurses' Health Study who completed a mailed questionnaire about risk factors in 1994 and had no history of heart disease at that time. Participants were followed through 2004 for the occurrence of CHD. We estimated each woman's 10-year relative risk of CHD using YDR, and we compared the estimated YDR relative risk category (ranging from "very much below average" to "very much above average") to the observed relative risk for each category using logistic regression. We also examined the discriminatory accuracy of YDR using concordance statistics (c-statistics). Results: There were 1165 CHD events during the 10-year follow-up period. Compared to the "about average" category, the observed age-adjusted relative risk was 0.43 (95 % confidence interval: 0.33, 0.56) for the "very much below average" category and 2.48 (95 % confidence interval: 1.68, 3.67) for the "very much above average" category. The age-adjusted c-statistic for the model including the YDR relative risk category was 0.71 (95 % confidence interval: 0.69, 0.72). The model performed better in younger than older women. Conclusion: The YDR tool appears to have moderate validity for estimating 10-year relative risk of CHD in this population of middle-aged women. Further research should aim to improve the tool's performance and to examine its validity in other populations.