External validation of the UKPDS risk engine in incident type 2 diabetes: a need for new type 2 diabetes-specific risk equations

Objective: To evaluate the performance of the United Kingdom Prospective Diabetes Study (UKPDS) Risk Engine for predicting the 10-year risk of cardiovascular disease endpoints in an independent cohort of UK patients newly diagnosed with type 2 diabetes.Research Design and Methods: This was a retrospective cohort study using routine healthcare data collected between April 1998 and October 2011 from around 350 UK primary-care practices contributing to the Clinical Practice Research Datalink (CPRD). Participants comprised 79,966 patients aged between 35 and 85 years (388 269 person years) with 4,984 cardiovascular events. Four outcomes were evaluated: first diagnosis of coronary heart disease (CHD), stroke, fatal CHD, and fatal stroke.ResultsAccounting for censoring , the observed versus predicted ten-year event rates were as follows: CHD 6.1% vs 16.5%, fatal CHD 1.9% vs 10.1%, stroke 7.0% vs 10.1%, and fatal stroke 1.7% vs 1.6%, respectively. The UKPDS-RE showed moderate discrimination for all four outcomes, with the concordance-index values ranging from 0.65 to 0.78.Conclusions: The UKPDS stroke equations showed calibration ranging from poor to moderate; however, the CHD equations showed poor calibration and considerably overestimated CHD risk. There is a need for revised risk equations in type 2 diabetes