Silent CAD and 5-year outcome in asymptomatic patients with type 2 diabetes with abnormal ECG in the DIAD study

Objectives The aim of the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study was to assess the prevalence of silent ischemia (SI) and 5-year outcome in patients with type 2 diabetes. 1,153 patients met criteria, 30 (2.6%) of which were not eligible because of abnormal rest ECG (Q-waves, LBBB, ST abnormalities). The remaining 1,123 patients were randomized to screening or no screening with vasodilator stress myocardial perfusion imaging (MPI). The present analysis focuses on the 30 patients with abnormal ECG.

Methods All 30 patients with abnormal ECG (ABN) had vasodilator stress MPI and were followed at 6-months intervals for 5 years. The prevalence of SI and occurrence of death, non-fatal MI and coronary revascularization (cardiac events) in ABN patients and randomized (RAND) patients were compared.

Results 12 of 30 ABN patients (40%) had an abnormal stress MPI compared to the 22% of RAND patients (p< 0.05). During 5 years follow up 6 (20%) out of the 30 original patients had cardiac outcomes, including 3 revascularizations (2 CABG, 1 PTCA), 1 fatal MI, 1 non-fatal MI, and 1 patient with high risk stress MPI results, compared to 8% patients from the RAND group (p< 0.05).

Conclusions 40% of patients who were excluded from the DIAD study because of their baseline ECG abnormalities had an abnormal stress MPI (SI), compared to only 22% of patients in DIAD with normal ECG. Total cardiac event rate in 5 years was 20% in ABN patients who had follow up, compared to only 8% in RAND patients. This study supports the American Diabetic Association guidelines, which recommend CAD screening in asymptomatic diabetic patients with abnormal baseline ECG.