Statistical Error in Interpretation of Aneurysm Coil Results

To the Editor:We read with interest the recent report by Bendszus et al1 regarding the efficacy of new “bioactive” coils for cerebral aneurysm therapy. The authors note a “statistically significant” difference between outcomes in aneurysms treated with the Cerecyte coil and a matched pair cohort treated with bare platinum coils, with superior long-term occlusion rate for the Cerecyte group.We wish to call attention to a basic statistical error in their report, an error that lowered the calculated probability values to half of their true value, which might lead the reader to make an incorrect conclusion regarding the statistical superiority of Cerecyte coils. In the methods section, the authors state that 2-sided Fisher exact tests were performed “for comparison of the initial treatment …