Can the Results be Explained by Poor Randomization and Nonpertinent Comparisons?

Abstract

To the Editor: I am writing regarding the article, “Anti-Ischemic and Anti-Anginal Effects of Thoracic Epidural Anesthesia Versus Those of Conventional Medical Therapy in the Treatment of Severe Refractory Unstable Angina Pectoris” by Olausson et al.1 While doing comparative graphs for a lecture, I found several inconsistencies in the article that diminish its scientific value. The main inconsistency is found in Table 1. During a run-in period, the patients were treated with both nitroglycerin and heparin infusions for 82±18 versus 122±20 and 53±7 versus 104±13 hours, respectively, for controls and the group with thoracic epidural anesthesia (TEA). These differences were reported as nonsignificant by the authors. However, when recalculating the statistics, I found values of P <0.14 and P <0.0015 for the nitroglycerin and heparin infusions, respectively. Thus, at least in terms of the heparin infusion, it seems that the patients might not have been properly randomized. In addition, Tables 2 and 3 contain several inconsistencies. …