Performance of the UKPDS Outcomes Model for Prediction of Myocardial Infarction and Stroke in the ADDITION-Europe Trial Cohort

OBJECTIVES: We assessed the performance of the UK Prospective Diabetes Study (UKPDS) outcomes model in predicting the risk of myocardial infarction (MI) and stroke in the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care (ADDITION-Europe) a trial cohort of patients with screen-detected type 2 diabetes from the United Kingdom, Denmark, and The Netherlands. METHODS: We estimated the 5-year accumulated risk of MI and stroke for 2899 screen-detected people with type 2 diabetes by using the UKPDS outcomes model (version 1.3). We compared the predicted and actual risks by country and by intervention group (routine care; intensive multifactorial treatment). We assessed discrimination and goodness of fit by using area under receiver operating characteristic curves and the Hosmer-Lemeshow chi-square test. Multiple imputations were used to overcome missing data. RESULTS: The UKPDS outcomes model overestimated the risk of MI and stroke. Mean predicted/actual ratios of 5-year accumulated risk were 2.31 for MI in the routine care group and 3.97 in the intensive multifactorial treatment group and 1.59 and 1.48 for stroke, respectively. The differences in absolute risk between the intervention groups were underestimated for MI (observed vs. predicted: 0.0127 vs. 0.0009) and slightly overestimated for stroke (-0.0013 vs. -0.0004). The area under the receiver operating characteristic curve was 0.72 (95% confidence interval 0.66-0.79) for MI and 0.70 (95% confidence interval 0.64-0.77) for stroke. The Hosmer-Lemeshow test statistic was nonsignificant in all groups. The model performed better in absolute risk prediction in Denmark and the United Kingdom than in The Netherlands. CONCLUSIONS: The UKPDS outcomes model has moderate discriminatory ability in the ADDITION-Europe trial cohort but overestimated absolute risk. The model may need updating for cardiovascular disease risk prediction in contemporary diabetes populations where patients may be diagnosed earlier in the disease trajectory and in whom cardiovascular risk is therefore lower.