AGE-ASSOCIATED RISKS OF PROPHYLACTIC ANTICOAGULATION IN THE SETTING OF HIP FRACTURE

PURPOSE: Controversy exists as to whether patient age, either independ ently or as a marker of concomitant illness or medication use, is asso ciated with the dose or complication rate of warfarin prophylaxis. The aim of this study was to assess this relationship in patients receivi ng warfarin prophylaxis after hip fracture repair. PATIENTS AND METHOD S: We undertook a retrospective cohort study of 215 patients 55 years of age or greater who underwent surgery for a fractured hip between Ja nuary 1, 1990, and December 31, 1991, and received warfarin prophylaxi s. The mean age was 78.9 (SD 9.5) years. The average daily warfarin do se, the decrease in hemoglobin in the postoperative period, and the ra te of bleeding complications were assessed. RESULTS: Elderly patients required a significantly lower average daily warfarin dose than younge r patients. This effect persisted even after controlling for the numbe r of medical conditions, number of medications on admission, proportio n of time the international normalized ratio (INR) was in therapeutic range, and gender. Postoperative hemoglobin decrease was associated wi th patient age as well as with the use of antibiotics postoperatively. Factors associated with bleeding complications included a history of alcohol abuse and a smaller proportion of time spent in the targeted a nticoagulant range. CONCLUSIONS: Older age itself and not as a marker for polypharmacy or increased number of medical conditions is associat ed with lower requirements for warfarin and a greater hemoglobin decre ase postoperatively even when the proportion of time the INR fell with in the therapeutic range is controlled. Advanced patient age, in this study, was not associated with an increased incidence of bleeding comp lications.