Results:

The prevalence of SMI in the full cohort of 4,827 increased progressively from 17.5% (845 patients) at baseline to 30.1% (680 of 2,259 patients) at 12 years. The presence of Q waves was typically transient, with 53% of those with SMI at baseline also having electrocardiograms (ECGs) of an SMI at year 3. Median follow-up was 17 years. Of 1,967 patients with complete baseline data (37% of total UKPDS cohort), 326 (16.6%) had ECG evidence of SMI at enrollment. Those with SMI were more likely to be older, female, sedentary, and nonsmokers 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. Evidence of an SMI at the time of diagnosis of T2D was associated with a 49% increased rate of subsequent fatal MI and a 26% increased rate of all-cause mortality after adjustment for conventional cardiovascular risk factors. Fully-adjusted hazard ratios (95% confidence interval) for those with, versus 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 nonfatal MI, and for first nonfatal MI, were nonsignificant. 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.