C.W. Colwell Jr. replies:
Drs. Bottaro and Ceresetto appropriately noted that the definitions of major and minor bleeding in prophylaxis protocols have differed widely depending upon the study. We agree this is true1,2, and it was the basis for our decision to use a direct comparator rather than to use bleeding rates from previous studies with varying criteria. We set the criteria for major and minor bleeding on the basis of the participating surgeons’ concerns before the initiation of the study, and both cohorts were judged by the same criteria. The fact that the study was randomized and prospective did not allow any of the investigators to choose a specific patient for one cohort or the other. The numbers of patients who fell into the major or minor bleeding categories were then tabulated; the data were analyzed and reported in Table II. Adjudication occurred for every major and minor bleed for accuracy. The patients who did not have a major or minor bleeding event were not adjudicated.
To question our definition of major bleeding is reasonable, as it is reasonable to question the definitions of major and minor bleeding in previous studies. As in those studies, one can only evaluate the results and quality of the individual study on how one thinks bleeding should be defined. Orthopaedic surgeons worldwide have accepted an increased bleeding rate when utilizing pharmacologic protocols to obtain better efficacy, i.e., lower rates of deep vein thrombosis and pulmonary embolism.
Our study demonstrates that a modality is now available to significantly decrease these defined rates of major bleeding with no apparent difference in efficacy. A new study is under way to document either superiority or noninferiority with respect to efficacy with use of this methodology.