Evaluating gender differences in prognosis following SPECT myocardial perfusion imaging among patients with diabetes and known or suspected coronary disease in the modern era.

Background: Previous data suggested that diabetic women were at greater risk for future cardiac events than diabetic men. Increasing awareness of coronary artery disease (CAD) in women and advances in the management of CAD may have changed this paradigm.
Objective: To investigate gender differences in prognosis among patients with diabetes who were clinically referred for single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI).
Methods: Patients with diabetes undergoing SPECT-MPI from 1996 to 2006 were followed for 5 years or until cardiac death or non-fatal myocardial infarction. Clinical characteristics and nuclear parameters were compared with χ (2) and t tests. Multivariable Cox regression controlled for baseline differences and tested the impact of gender on survival.
Results: A total of 4,628 SPECT-MPI patients with diabetes (50% women, mean age 63 ± 12 years) were analyzed. There were 380 events, with rates higher in men (10% vs 7%, P < .001). Patients of either gender with abnormal scans had higher event rates than patients with normal scans. There were fewer cardiac events in diabetic females with no known CAD and normal scans compared to similar males (P = .044). However, diabetic males and females with known CAD had similar event rates for all degrees of perfusion abnormalities. Only age, history of heart failure, nuclear perfusion defect, and LVEF predicted survival; gender did not. LVEF ≤ 50% had the strongest association with cardiac events (hazard ratio = 2.518, 95% confidence interval, 1.922-3.298).
Conclusion: Cardiovascular outcomes among patients with diabetes, regardless of a history of CAD, were similar in women and men. The size and severity of stress-induced perfusion abnormalities predicted outcomes equally in both genders.