I read with interest the article by Hull et al1 comparing long-term dalteparin therapy with short-term in-hospital warfarin therapy in patients undergoing hip arthroplasty. I would like to make the following comments regarding this study.
Because the study compared long-term dalteparin therapy (average of 35 days) with short-term warfarin therapy (average of 6 days), the conclusions of the study do not necessarily mean that dalteparin is superior to warfarin in patients with hip arthroplasty. Had these agents been administered for the same period (average of 35 days), better and more balanced conclusions could have been made about their comparative efficacy. I concur with the authors' valid observation about the currently shorter in-hospital stay for most hip arthroplasty patients. The average in-hospital stay at my institution ranges from 3 to 4 days, depending on the individual orthopedic surgeon. Because the currently short in-hospital stay for hip arthroplasty patients was quoted as a potential hindrance towards an adequate anticoagulation period in these patients, why wasn't warfarin therapy extended as long as the dalteparin arm of the study?