Comparison of the Framingham and United Kingdom Prospective Diabetes Study cardiovascular risk equations in Australian patients with type 2 diabetes from the Fremantle Diabetes Study

Abstract

Objective: To assess the performance of the Framingham and United Kingdom Prospective Diabetes Study (UKPDS) cardiovascular risk equations in Australian patients with type 2 diabetes who were initially free of cardiovascular disease (CVD).

Design and setting: The Fremantle Diabetes Study (FDS), a community-based longitudinal observational study; data for the period 1993-2006 were used.

Patients: Of the 815 FDS participants with type 2 diabetes who were initially CVD-free, 791 (97%) were eligible for assessment using the UKPDS equations, and 697 (86%) using the Framingham equation.

Main outcome measures: CVD endpoints during 5 years of follow-up. For the UKPDS equations, these were fatal myocardial infarction (MI) or sudden death (fatal coronary heart disease [CHD]); hospitalisation for/with or death from MI or sudden death (all CHD); fatal stroke; and all stroke. For the Framingham equation, they were all MI, sudden death or angina pectoris (CHD).

Results: During follow-up to first CVD event, death or 5 years, there were 38 MIs (11 fatal) and 23 strokes (13 fatal) in the UKPDS-assessable cohort of FDS participants. The UKPDS risk equations for all CHD, fatal CHD, and all stroke overestimated the number of events by 6.5, 2.8 and 1.8 times, respectively. The risk equation for fatal stroke underestimated the number of events by 38%. The UKPDS CHD risk equations showed modest discrimination and poor calibration, while the stroke risk equations showed good discrimination and calibration. The Framingham equation predicted 28% fewer CHD events than occurred (93 v 130), and discrimination and calibration were poor.

Conclusions: While the UKPDS stroke risk equations performed relatively well, the UKPDS and Framingham CHD risk equations are not suitable for predicting risk in Australians with type 2 diabetes.