When diabetes mellitus patients were treated with oral agents they saw significant improvements in adverse events at one year after PCI, according to the results of a study published in the February issue of the American Heart Journal. However, efforts are still needed to inmprove the outcomes of these patients because the rates of death and MI following PCI are still high.
Patients with diabetes mellitus undergoing PCI are at an increased risk for restenosis, target vessel revascularization, late MI and death, therefore, more data are needed to evaluate the treatment regiments for diabetes mellitus and clinical outcomes.
Elizabeth M. Holper, MD, MPH, from the division of cardiology at the University of Texas Southwestern Medical Center in Dallas, and colleagues used the National Heart, Lung and Blood Institute (NHLBI) Dynamic Registry to evaluate the outcomes of 2,838 patients with diabetes mellitus who underwent PCI procedures.
The data was collected in five waves: wave one was between July 1997 and February 1998, wave two was between February and June 1999, wave three was between October 2001 and March 2002, wave four was between February and May 2004 and wave five was between February and August 2006.
The patients were medically treated for diabetes in waves one (insulin treated 215 patients, oral agent 338 patients), two (insulin 193 patients, oral agent 312 patients), three (insulin 194 patients, oral agent 333 patients), four (insulin 229 patients, oral agent 382 patients) and five (insulin 235 patients, oral agent 407 patients).
The researchers reported that the one-year mortality rate in patients with medically treated diabetes mellitus was 7.3 percent. These same rates were 9.7 percent in patients treated with insulin and 5.9 percent among patients treated with oral agents.
The overall cohort of patients saw significant reductions in mortality; however, the rates of MI saw no change. There was also no change in the one-year mortality rates of patients treated with insulin, but patients treated with oral agents died less frequently in the later waves.
The authors also reported that there was a reduction in the need to perform repeat PCI procedures one year after discharge in all treatment and cohorts. Additionally, the researchers reported that one-year MACE rates were lower in the later recruitment waves in both patients treated with insulin and those treated with oral agents.
Holper and colleagues suggested that the reason for the higher MI rates in diabetic patients treated with insulin compared to those treated with oral agents could be due to disease severity.
The authors said that lower risk of repeat PCI and revascularizations took place in waves four and five, after the approval of drug-eluting stents (DES), hinting that these stents would be an important strategy to reduce repeat PCI procedures in diabetics.
“It is possible that a component of the subsequent MI rate will be reduced in the setting of longer drug-eluting stents placed in insulin-treated diabetic patients, which will require long-term follow-up,” the authors wrote. “However, reduction of the overall mortality of insulin-treated patients who require PCI will likely require focus on alternative therapeutic strategies outside of the catheterization laboratory.”
The researchers concluded that more studies are necessary to evaluate the differences between therapeutic strategies in order to reduce intermediate-term outcomes in diabetics who are undergoing PCI procedures and who require insulin.