Risk of bacterial infection associated with allogeneic blood transfusion among patients undergoing hip fracture repair

BACKGROUND:The relationship between allogeneic blood transfusion and bacter ial infection remains uncertain. An increased risk of bacterial infection w ould represent the most important risk of allogeneic transfusion, because v iral disease transmission has become so rare. STUDY DESIGN AND METHODS: A retrospective cohort study of 9598 consecutive hip fracture patients at least 60 years old who underwent surgical repair w as performed. The primary outcome was serious bacterial infection, defined as bacteremia, pneumonia, deep wound infection, or septic arthritis or oste omyelitis. Secondary outcomes included two individual infections, pneumonia and urinary tract infection (UTI), and the cost of infection. Hospital cos t of infection was assessed by linking the study population to Medicare dat a. RESULTS: Fifty-eight percent of patients received at least one transfusion. Serious bacterial infection occurred in 437 patients (4.6%); 28.8 percent of this group died during the hospital stay. Pneumonia occurred in 361 pati ents (3.8%) and UTI occurred in 1157 patients (12.1%). The adjusted risk of serious bacterial infection associated with transfusion was 1.35 (95% CI, 1.10-1.66). The adjusted risk for pneumonia was 1.52 (95% CI, 1.21-1.91), a nd that for UTI was 1.03 (95% CI, 0.91-1.17). A dose-response relationship was present for serious bacterial infection (p = 0.001) and pneumonia (p = 0.001). The cost of hospitalization was $14,000 greater for patients with s erious infection than for patients without infection. CONCLUSION: Blood transfusion is associated with a 35-percent greater risk of serious bacterial infection and a 52-percent greater risk of pneumonia. Postoperative infections are costly. The risk of bacterial infection may be the most common life-threatening adverse effect of allogeneic blood transf usion.