STUDY SUPPORTS INTERVENTION IN NSTEMI DIABETICS

July 2, 2012 (Boston, Massachusetts) — A meta-analysis of nearly 10 000 patients in nine trials supports early intervention rather than a conservative approach for non-ST-elevation myocardial infarction (NSTEMI) patients with diabetes [1].

Diabetes increases the risk of recurrent cardiovascular events and complications after percutaneous intervention or bypass surgery, so the relative benefit of an invasive strategy in this patient population has been unknown, according to study authors Dr Michelle O'Donoghue (Brigham and Women's Hospital, Boston, MA) and colleagues. The latest European Society of Cardiology and American College of Cardiology/American Heart Association guidelines included diabetics among the patient groups for whom the invasive strategy is preferred, but O'Donoghue et al point out that the only randomized trials with substudies supporting this recommendation are FRISC II and TACTICS–TIMI 18. FRISC II showed comparable reductions in death or MI with the invasive strategy in both diabetics and nondiabetics. TACTICS-TIMI 18 found the invasive strategy reduced death, MI, and ACS rehospitalization in both diabetics and nondiabetics by about the same percentage. In both trials, there was a trend toward more benefit in diabetics.

Published in the July 10, 2012 issue of the Journal of the American College of Cardiology, the meta-analysis by O'Donoghue et al found that 18.1% of the NSTEMI ACS patients in the nine included trials had diabetes. Comparing the invasive and conservative strategies, the relative risk of death, nonfatal MI, or rehospitalization with an acute coronary syndrome were similar for diabetic patients (RR 0.87) and nondiabetic patients (RR 0.86) (p for interaction=0.83). Invasive strategies reduced nonfatal MI in diabetic patients (RR 0.71), but not in nondiabetic patients (RR 0.98) compared with conservative strategies (p for interaction=0.09).

The absolute risk reduction in MI with an invasive strategy was greater in diabetics than in nondiabetics (absolute risk reduction 3.7% vs 0.1%; p for interaction=0.02), and there were no differences in death or stroke between the groups (p for interactions=0.68 and 0.20, respectively).

The data were also stratified by the presence or absence of creatine kinase-myocardial band (CK-MB) or troponin and showed that elevation of these biomarkers identified nondiabetics with a better chance of benefiting from the invasive approach (RR 0.68) than the conservative approach. Also, diabetics with or without elevated biomarkers had a comparable reduction in death or MI with the invasive strategy. ST-segment deviation did not identify a group of diabetics likely to gain a greater benefit from the invasive approach, the authors note.

This study--the first large meta-analysis comparing the benefits of an invasive strategy between diabetic and nondiabetic patients with NSTEMI ACS--"suggest that specific high-risk features such as diabetes mellitus and cardiac biomarkers are useful to help identify those individuals who will benefit from an invasive approach in [NSTEMI]-ACS."

O'Donoghue reports no potential conflicts of interest related to this research. Disclosures for the coauthors are listed in the paper.