In a study of asymptomatic patients with type 2 diabetes, women had a lower cardiac event rate than men, although screening for silent myocardial ischemia did not benefit either sex.…
According to Suman Tandon, MD, of Yale University, through 4.8 years of follow-up, women were less likely than men to suffer cardiac death or have a nonfatal myocardial infarction (1.7% versus 3.8%, P=0.05).
Cardiac event rates were not significantly different between patients who were screened with adenosine-stress myocardial perfusion imaging and those who were not screened, for either men (3.8% versus 3.9%) or women (1.5% versus 2%). In the post-hoc analysis, however, the researchers identified a high rate of cardiac events (11%) in men with high risk according to the United Kingdom Prospective Diabetes Study (UKPDS) risk tool, which takes into account duration of diabetes, HbA1c, and traditional cardiovascular risk factors.
“Although the conclusions of DIAD were that screening is not beneficial and does not affect outcomes, based on the results of this study, maybe the future screening studies need to be designed and focused on asymptomatic men with high-risk UKPDS scores,” Tandon concluded.
In DIAD, 1,123 asymptomatic patients with type 2 diabetes were randomized to receive myocardial perfusion scans to look for silent myocardial ischemia or to no screening.
The main results of the study, showed a lower-than-expected rate of silent myocardial ischemia (22%) and a low rate of cardiac events (2.9%) that were not affected by screening. Male gender was one of the significant predictors of cardiac events in the study, so Tandon and her colleagues undertook a post-hoc analysis to explore differences based on sex.
There were 522 women and 601 men in the trial, and about half were screened and half were not. In general, men and women were similar, with a mean age of 60, a mean duration of diabetes of 5.7 years, and a mean HbA1c of 6.94%. However, women had a significantly higher body mass index (31.7 versus 29.4 kg/m2) and total cholesterol level (198 versus 188 mg/dL), but a significantly lower serum creatinine (0.83 versus 1.02 mg/dL). All differences were significant at P<0.001.
The prevalence of abnormal myocardial perfusion scans was not significantly different between the sexes, although it was numerically higher in men (24% versus 19%, P=0.2). There was a nonsignificant trend toward fewer moderate-to-large screening abnormalities in women (P=0.07). Females had lower cardiac event rates during follow-up, but screening did not influence rates in either men or women.
However, there was a difference in the percentage of men and women in each UKPDS risk group. Females were more likely to be low risk (71% versus 24%) and less likely to be intermediate risk (23% versus 54%), and high risk (3% versus 21%). The split was significantly different between the sexes (P<0.001).
Cardiac event rates did not differ between men and women in the low or intermediate groups, but in the high-risk group, 11.2% of men and 0% of women had an event. Tandon said low patient numbers precluded any definitive statistical conclusions.
The International Conference of Non-Invasive Cardiovascular Imaging, Tandon S, et al “Screening asymptomatic patients with type 2 diabetes for silent myocardial ischemia: important gender differences from the DIAD study” ICNC 2011; Abstract 239.