Patients with diabetes undergoing PCI have similar outcomes whether or not they receive insulin

After risk adjustments, patients with insulin-treated diabetes and non-insulin treated diabetes who underwent PCI had similar outcomes, according to a prespecified subgroup analysis of a randomized trial.

In addition, patients who received everolimus-eluting stents had better outcomes than those who received paclitaxel-eluting stents.

Lead researcher Sripal Bangalore, MD, MHA, of the New York University School of Medicine, and colleagues published their results online in JAMA Cardiology on April 20.

The researchers analyzed 1,830 patients with diabetes and coronary artery disease who underwent PCI and enrolled in the TUXEDO (Taxus Element vs Xience Prime in a Diabetic Population) trial.

Boston Scientific funded the TUXEDO trial, while this subgroup analysis was supported by research grants from Boston Scientific, Abbott Vascular and Medtronic.

From June 23, 2011, to March 12, 2014, the patients were randomized in a 1:1 ratio to receive a paclitaxel-eluting stent or an everolimus-eluting stent. All patients received oral aspirin and a loading dose of clopidogrel, prasugrel or ticagrelor before undergoing PCI. They were then prescribed dual antiplatelet therapy (aspirin plus clopidogrel, prasugrel or ticagrelor) twice daily for at least 12 months after stent implantation. Patients had follow-up visits at 30 days, 180 days and one year after the PCI.

Of the patients, 40.8 percent received insulin and 59.2 percent did not receive insulin during the trial. Patients with insulin-treated diabetes were more likely to be women, had a higher body mass index, had a longer duration of diabtes, had a higher hemoglobin A1c, were more likely to have undergone prior PCI, were more likely to have chronic kidney disease and were more likely to be asymptomatic. They also had lower left ventricular ejection fraction and were less likely to have experienced prior MI and less likely to currently smoke.

Patients with insulin-treated diabetes had significantly higher rates of target vessel failure (5.6 percent vs. 3.3 percent), major adverse cardiovascular events (6.0 percent vs. 3.7 percent), death or MI (5.8 percent vs. 3.2 percent) and cardiac death or MI (4.7 percent vs. 2.9 percent). They also had significantly higher rates of death (3.5 percent vs. 1.7 percent), Q-wave MI (0.9 percent vs. 0.2 percent) and subacute stent thrombosis (1.1 percent vs. 0.3 percent).

However, after the researchers used propensity scores to adjust for differences in the groups, the higher risk of cardiovascular events in patients with insulin-treated diabetes was not statistically significant.

The researchers defined target vessel failure as the composite of cardiac death, target vessel MI or ischemia-driven target vessel revascularization. They defined major adverse cardiovascular events as the composite of cardiac death, MI or ischemia-driven target lesion revascularization.

Of the patients with insulin-treated diabetes, everolimus-eluting stents significantly reduced the rate of target vessel failure, major adverse cardiovascular events, any stent thrombosis, definite stent thrombosis, target lesion revascularization and target vessel revascularization compared with paclitaxel-eluting stents.

Of the patients who were not receiving insulin, everolimus-eluting stents significantly reduced the rate of target vessel-related MI compared with paclitaxel-eluting stents. However, the researchers noted that the absolute risk reduction for target vessel failure with everolimus-eluting stents was greater among patients who were receiving insulin compared with those who were not receiving insulin.

The researchers cited a few limitations of the study, including that the study was not designed or powered to evaluate outcome differences in the insulin treated and non-insulin treated subgroups. They added that the multivariable model did not account for unmeasured confounders such as patient frailty, while physicians decided whether to treat patients with insulin.