More than a million surgeries are performed annually in the United States for hip or knee arthroplasty or hip fracture stabilization. One-fifth of these patients have blood transfusions during their hospital stay. Increases in transfusion rates have caused concern about increased adverse events from unnecessary transfusions.
We systematically reviewed randomized trials examining the effect of restrictive vs liberal transfusion thresholds on patients having major orthopedic surgery. Study results were meta-analyzed with a random-effects model and heterogeneity was tested with the I2 statistic. Study risk of bias was assessed using a modified Jadad scale and evidence strength was measured using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system.
A total of 504 published articles were screened, and 15 met inclusion criteria. The articles described 9 randomized trials, most comparing transfusion thresholds of 8 vs 10 g/dL hemoglobin. All involved hip or knee arthroplasty and/or hip fracture patients.
Moderate-strength evidence suggested a reduction in need for transfusion (relative risk, 0.53; 95% confidence interval [CI], 0.39-0.71; I2 = 95%) and mean number of units transfused (−0.95 units, 95% CI, –1.48 to −0.41, I2 = 98%). There was a possible reduction in overall infections with more restrictive transfusion thresholds, although the result was not statistically significant (relative risk, 0.71; 95% CI, 0.47-1.06; I2 = 54%). Moderate-strength evidence suggested no differences in other clinical outcomes between the groups. Limitations included incomplete blinding, inconsistency, and imprecision.
Moderate-strength evidence suggests that restrictive transfusion practices reduce utilization of transfusions and may decrease infections without increasing adverse outcomes in major orthopedic surgery.