Exercise stress tests for detecting myocardial ischemia in asymptomatic patients with diabetes mellitus.

The predominant cause of death in diabetes mellitus (DM) is coronary artery disease (CAD). Little is known about prevalence of silent ischemia in developing nations. We compared prevalence of silent ischemia in DM to a control group by exercise myocardial perfusion imaging (MPI) and electrocardiogram (ECG) in developing nations. The prospective multinational Ischemia Assessment with Exercise imaging in Asymptomatic Diabetes study recruited participants at 12 sites in Asia, Africa, and Latin America. DM participants were age- and gender-matched 2:1 to non-DM individuals with ≥1 CAD risk factor. Subjects underwent exercise tests that were interpreted in core labs in blinded fashion. The study included 392 DM and 205 control participants. Among participants with diagnostic ECGs, a similar proportion of DM and controls had ischemic ECG (15% vs 12%, p = 0.5). A significantly higher proportion of DM group had MPI abnormalities compared with controls (26% vs 14%, p <0.001). In participants with ischemia on MPI, only 17% had ischemic ECG, whereas in those without ischemia on MPI, 10% had ischemic ECG. In a multivariable model, DM was independently associated with abnormal MPI (odds ratio 2.1, 95% confidence interval 1.3-3.5, p = 0.004). Women were less likely to have ischemia by MPI than men (10% vs 30%, p <0.001) and concordance between ECG and MPI was much worse in women. In conclusion, in this large prospective study, asymptomatic DM participants had (1) more ischemia by exercise MPI than ECG, (2) more ischemia by MPI but not ECG than control group, and (3) ischemia by MPI was less in women than men.