Early invasive vs conservative treatment strategies in women and men with unstable angina and non-ST-segment elevation myocardial infarction - A meta-analysis

Context Although an invasive strategy is frequently used in patients with non - ST-segment elevation acute coronary syndromes ( NSTE ACS), data from some trials suggest that this strategy may not benefit women. Objective To conduct a meta- analysis of randomized trials to compare the effects of an invasive vs conservative strategy in women and men with NSTE ACS. Data Sources Trials were identified through a computerized literature search of the MEDLINE and Cochrane databases ( 1970- April 2008) using the search terms invasive strategy, conservative strategy, selective invasive strategy, acute coronary syndromes, non- ST- elevation myocardial infarction, and unstable angina. Study Selection Randomized clinical trials comparing an invasive vs conservative treatment strategy in patients with NSTE ACS. Data Extraction The principal investigators for each trial provided the sex- specific incidences of death, myocardial infarction ( MI), and rehospitalization with ACS through 12 months of follow- up. Data Synthesis Data were combined across 8 trials ( 3075 women and 7075 men). The odds ratio ( OR) for the composite of death, MI, or ACS for invasive vs conservative strategy in women was 0.81 ( 95% confidence interval [ CI], 0.65- 1.01; 21.1% vs 25.0%) and in men was 0.73 ( 95% CI, 0.55- 0.98; 21.2% vs 26.3%) without significant heterogeneity between sexes ( P for interaction=. 26). Among biomarker- positive women, an invasive strategy was associated with a 33% lower odds of death, MI, or ACS ( OR, 0.67; 95% CI, 0.50- 0.88) and a nonsignificant 23% lower odds of death or MI ( OR, 0.77; 95% CI, 0.47- 1.25). In contrast, an invasive strategy was not associated with a significant reduction in the triple composite end point in biomarker- negative women ( OR, 0.94; 95% CI, 0.61- 1.44; P for interaction=. 36) and was associated with a nonsignificant 35% higher odds of death or MI ( OR, 1.35; 95% CI, 0.78- 2.35; P for interaction=. 08). Among men, the OR for death, MI, or ACS was 0.56 ( 95% CI, 0.46- 0.67) if biomarker- positive and 0.72 ( 95% CI, 0.51- 1.01) if biomarker- negative ( P for interaction=. 09). Conclusions In NSTE ACS, an invasive strategy has a comparable benefit in men and high- risk women for reducing the composite end point of death, MI, or rehospitalization with ACS. In contrast, our data provide evidence supporting the new guideline recommendation for a conservative strategy in low- risk women.