Prevalence and Predictors of Ischemia and Outcomes in Outpatient Diabetic Patients Referred for SPECT Myocardial Perfusion Imaging

Diabetes mellitus (DM) is a highly-prevalent comorbidity that affects more than 194 million worldwide and is closely associated with coronary artery disease (CAD).1 CAD is the leading cause of mortality in diabetic patients (accounting for 65–70% of deaths) and is also associated with high morbidity.2, 3 The diagnosis of CAD is complicated by the often atypical presentation of diabetic patients due to concomitant autonomic neuropathy and other disorders. Moreover, it is important to identify CAD early in these patients to optimize medical therapy and lifestyle modifications. It is especially important to identify and aggressively treat those at the highest risk of events. For these reasons, there is a high rate of referral for myocardial perfusion imaging (MPI) when symptoms develop in this population. Similarly, many asymptomatic diabetic patients deemed at high risk for silent ischemia are referred for stress imaging. The prognostic impact of ischemia together with other clinical and stress variables has previously been reported.4–7 However, the prevalence of ischemia and its ability to predict those who experience future cardiac events is less clear in a consecutive group of stable outpatient diabetic patients with or without symptoms referred for MPI in the current era. Accordingly, we sought to identify the prevalence and predictors of significant scintigraphic ischemia and subsequent cardiac events and assess the impact of gender, type of stress, and symptom status on these findings in a cohort of stable outpatients with diabetes referred for SPECT MPI.