A Pen-and-Paper Coronary Risk Estimator for Office Use With Patients With Type 2 Diabetes

Abstract

To develop a pen-and-paper coronary heart disease (CHD) 10-year risk estimator for patients with type 2 diabetes based on the United Kingdom Prospective Diabetes Study (UKPDS) risk equation (based on 4000 patients with diabetes but only available electronically). We used data collected from adults with type 2 diabetes from 6 primary care practices that participated in a randomized trial in Rochester, Minn; patients were enrolled in the study from July 2001 to December 2003, with follow-up through June 2004. We used multivariable linear regression of the CHD risk estimate to formulate prediction equations to estimate average (<15%), elevated, or high (>30%) 10-year CHD risk according to sex, age, diabetes duration, smoking, hemoglobin A1c level, systolic blood pressure, ratio of total cholesterol to high-density lipoprotein cholesterol, and microalbuminuria categories. We selected cut points for the predicted score, seeking to (1) maximize the number of patients with total agreement between our estimator and the UKPDS risk equation, (2) avoid any patient's risk being either overestimated or underestimated by 2 risk categories, and (3) overestimate rather than underestimate coronary risk. A total of 535 patients with type 2 diabetes participated in this study, 400 in the generation cohort and 135 in the validation cohort. Of the 400 patients in the generation cohort, our estimator had an 82% total agreement with the UKPDS calculation, 11% overestimated risk, and 7% underestimated UKPDS coronary risk (weighted kappa=0.77). Results were similar in the 135 patients in the validation cohort (kappa=0.79) and in an independent validation cohort of 52 patients attending a referral diabetes clinic (kappa=0.68). The pen-and-paper estimator facilitates the point-of-care estimation of coronary risk in situations in which use of a desktop or handheld version of the electronic UKPDS risk engine is not practical or feasible. In our experience, estimation of risk using this tool, when done with patients, can further patients' insight into their risk of coronary events, often leading to enlightened discussions about modification of Individual risk factors.