—We agree with Dr Collins and colleagues that the 33% reduction in risk of MI or death in patients treated with aspirin plus heparin compared with those treated with aspirin alone was not statistically significant. The P value for the 95% CI associated with the relative risk (RR) of 0.67 (95% CI, 0.44-1.02) was.057. Athough this P value does not meet the arbitrary cutoff of.05 required for statistical significance, it suggests a low probability (5.7%) that the findings occurred by chance. We believe that these findings are strengthened by the results of 2 recent trials that compared low-molecularweight heparin plus aspirin with aspirin alone in patients with unstable angina.1,2 In both studies, adding low-molecularweight heparin to aspirin reduced the risk of MI or death during treatment. If we had included these trials in our metaanalysis, we would have found a statistically significant summary RR of 0.56 (95% CI, 0.40-0.80).
Oler A, Whooley MA. Benefit of Heparin Plus Aspirin vs Aspirin Alone in Unstable Angina-Reply. JAMA. 1996;276(23):1874. doi:10.1001/jama.1996.03540230024016