Prognostic Significance of Silent Myocardial Infarction in Newly-Diagnosed Type 2 Diabetes: UKPDS 79
Background—We aimed to determine the prevalence of silent myocardial infarction (SMI) in people with newly-diagnosed type 2 diabetes (T2D), and its relationship to future myocardial infarction (MI) and all-cause mortality.
Methods and Results—We examined data from the 5,102 patients in the 30-year UK Prospective Diabetes Study (UKPDS) and used Cox proportional hazards regression to examine outcomes by SMI status. Of 1,967 patients with complete baseline data, 326 (16.6%) had ECG evidence of SMI (Minnesota codes 1.1 or 1.2) at enrolment. Those with SMI were more likely to be older, female, sedentary and non-smokers compared with those without SMI. Their mean blood pressure was greater despite more intensive antihypertensive treatment, they were more likely to be taking aspirin and lipid-lowering therapy, and they had a greater prevalence of microangiopathy. Fully-adjusted hazard ratios (95% CI) for those with, vs. those without, SMI in multivariate models that included UKPDS Risk Engine variables were 1.58 (1.22-2.05) for first fatal MI, and 1.31 (1.10-1.56) for all-cause mortality. Hazard ratios for first fatal or non-fatal MI, and for first non-fatal MI, were non-significant. The Net Reclassification Index showed no improvement when SMI was added to these models and the Integrated Discrimination Index showed that SMI marginally improved prediction of fatal MI and all-cause mortality.
Conclusions—Around one in six UKPDS patients with newly-diagnosed T2D had evidence of SMI, which was independently associated with an increased risk of fatal MI and all-cause mortality. However, identification of SMI does not add substantively to current UKPDS Risk Engine predictive variables.
Clinical Trial Registration Information—URL: http://www.controlled-trials.com. Identifier: ISRCTN number: 75451837.
- silent myocardial infarction
- myocardial infarction
- type 2 diabetes mellitus
- cardiovascular disease risk factors
- Received December 22, 2012.
- Accepted January 9, 2013.
- Copyright © 2013, Circulation