Health care-associated infection after red blood cell transfusion: a systematic review and meta-analysis.

IMPORTANCE: The association between red blood cell (RBC) transfusion strategies and health care-associated infection is not fully understood. OBJECTIVE: To evaluate whether RBC transfusion thresholds are associated with the risk of infection and whether risk is independent of leukocyte reduction. DATA SOURCES: MEDLINE, EMBASE, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, Cochrane Database of Sytematic Reviews, ClinicalTrials.gov, International Clinical Trials Registry, and the International Standard Randomized Controlled Trial Number register were searched through January 22, 2014. STUDY SELECTION: Randomized clinical trials with restrictive vs liberal RBC transfusion strategies. DATA EXTRACTION AND SYNTHESIS: Twenty-one randomized trials with 8735 patients met eligibility criteria, of which 18 trials (n = 7593 patients) contained sufficient information for meta-analyses. DerSimonian and Laird random-effects models were used to report pooled risk ratios. Absolute risks of infection were calculated using the profile likelihood random-effects method. MAIN OUTCOMES AND MEASURES: Incidence of health care-associated infection such as pneumonia, mediastinitis, wound infection, and sepsis. RESULTS: The pooled risk of all serious infections was 11.8% (95% CI, 7.0%-16.7%) in the restrictive group and 16.9% (95% CI, 8.9%-25.4%) in the liberal group. The risk ratio (RR) for the association between transfusion strategies and serious infection was 0.82 (95% CI, 0.72-0.95) with little heterogeneity (I2 = 0%; τ2 <.0001). The number needed to treat (NNT) with restrictive strategies to prevent serious infection was 38 (95% CI, 24-122). The risk of infection remained reduced with a restrictive strategy, even with leukocyte reduction (RR, 0.80 [95% CI, 0.67-0.95]). For trials with a restrictive hemoglobin threshold of <7.0 g/dL, the RR was 0.82 (95% CI, 0.70-0.97) with NNT of 20 (95% CI, 12-133). With stratification by patient type, the RR was 0.70 (95% CI, 0.54-0.91) in patients undergoing orthopedic surgery and 0.51 (95% CI, 0.28-0.95) in patients presenting with sepsis. There were no significant differences in the incidence of infection by RBC threshold for patients with cardiac disease, the critically ill, those with acute upper gastrointestinal bleeding, or for infants with low birth weight. CONCLUSIONS AND RELEVANCE: Among hospitalized patients, a restrictive RBC transfusion strategy was associated with a reduced risk of health care-associated infection compared with a liberal transfusion strategy. Implementing restrictive strategies may have the potential to lower the incidence of health care-associated infection.