An invasive or conservative strategy in patients with diabetes mellitus and non-ST-segment elevation acute coronary syndromes: a collaborative meta-analysis of randomized trials

Objectives: The purpose of this study was to conduct a meta-analysis to examine an invasive or conservative strategy in diabetic versus nondiabetic patients.

Background: Diabetic patients are at increased risk of cardiovascular events after an acute coronary syndrome, yet it remains unknown whether they derive enhanced benefit from an invasive strategy.

Methods: Randomized trials comparing an invasive versus conservative treatment strategy were identified. The prevalence of cardiovascular events through 12 months was reported for each trial, stratified by diabetes mellitus status and randomized treatment strategy. Relative risk (RR) ratios and absolute risk reductions were combined using random-effects models.

Results: Data were combined across 9 trials comprising 9,904 subjects of whom 1,789 (18.1%) had diabetes mellitus. The RRs for death, nonfatal myocardial infarction (MI), or rehospitalization with an acute coronary syndrome for an invasive versus conservative strategy were similar between diabetic patients (RR: 0.87; 95% confidence interval [CI]: 0.73 to 1.03) and nondiabetic patients (RR: 0.86; 95% CI: 0.70 to 1.06; p interaction = 0.83). An invasive strategy reduced nonfatal MI in diabetic patients (RR: 0.71; 95% CI: 0.55 to 0.92), but not in nondiabetic patients (RR: 0.98; 95% CI: 0.74 to 1.29; p interaction = 0.09). The absolute risk reduction in MI with an invasive strategy was greater in diabetic than nondiabetic patients (absolute risk reduction: 3.7% vs. 0.1%; p interaction = 0.02). There were no differences in death or stroke between groups (p interactions 0.68 and 0.20, respectively).

Conclusions: An early invasive strategy yielded similar RR reductions in overall cardiovascular events in diabetic and nondiabetic patients. However, an invasive strategy appeared to reduce recurrent nonfatal MI to a greater extent in diabetic patients. These data support the updated guidelines that recommend an invasive strategy for patients with diabetes mellitus and non-ST-segment elevation acute coronary syndromes.