Sat., 10/15/11 Peds, Ger, Hip, Femur & IP, Paper #75, 11:03 am OTA-2011
DVT Prophylaxis and Mortality After Hip Fracture
Pierre Guy, MD1; Rik W. Nienhuis, MD2; Kelly A. Lefaivre, MD1;
Lisa Kuramoto1; Boris Sobolev, PhD1;
1University of British Columbia, Vancouver, British Columbia, Canada;
2University of Groningen, Groningen, The Netherlands
Purpose: DVT chemoprophylaxis following hip fracture is increasingly recommended. The elderly hip fracture population is known to be at risk for development of postoperative deep vein thrombosis (DVT) and pulmonary embolism (PE), grouped as VTE (venous thromboembolism). These risks are recognized for hip fractures in the literature; however, the benefits of prophylactic anticoagulation to lower the risk of VTE and death with low molecular-weight heparins or other measures are not as well quantified. Recently, low molecular- weight heparin has been recommended by the American College of Chest Physicians for postoperative prophylaxis in hip fracture cases. We took the opportunity of a varied VTE chemical prophylaxis practice in our institution to assess clinical risks and benefits related to complications and 30-day mortality.
Methods: 1297 admissions for >65-year-old patients with operatively treated hip fractures were identified by our orthopaedic trauma database between January 2003 and December 2007. The medical records were reviewed to ascertain the prophylaxis method, clinical data, complications, and in-hospital mortality. Postdischarge mortality and pharmacologic therapy were captured through our governmental Vital Statistics office and Pharmanet databases, using personal health number and date of birth as matching criteria.
Results: 1202 files had complete information and formed the cohort. Mean age was 83.6 years (range, 66-106 years). 75.4% were female. 431 patients (35.9%) received low molecular-weight heparin (LMWH) chemoprophylaxis. 91 patients (7.6%) developed a wound problem and 8 required repeat surgery. χ2 test revealed no association between wound problems and LMWH chemoprophylaxis (P = 0.94). Overall, “all causes” mortality rate was 7.4% (89 patients) with 70 patients dying in hospital (5.8%) or discharged and dying within 30 days of surgery (19 patients [1.6%]). Discharged deaths occurred at a mean 19 days (standard deviation 8) postsurgery. χ2 test revealed no association between mortality and LMWH chemoprophylaxis separately for all 3 time periods (P = 0.66, 0.190, 0.124, respectively).
Conclusion: Review of this “natural experiment” in a real-world setting of varied VTE prophylaxis practices after hip fracture failed to demonstrate an association between the use of LMWH chemoprophylaxis and wound complications or mortality. This constitutes the first larger scale “comparative effectiveness” assessment in this clinical setting. Strengths include the reliable outcome measure; limitations include surgeon randomized, retrospective data and small event count. These findings could raise controversy in clinical and policymaking settings by quantifying the association between VTE preventative measures and mortality in a real-world setting, but it will also importantly help define the sample size required for large clinical trials or population-based assessments using death, wound problems, and cost-effectiveness as an outcome. As our aged population steadily grows, clinicians, health administrators, and policymakers will seek such important studies for decision-making.
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• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.