The effect of perioperative blood transfusion on 30-day mortality and morbidity in elective spine surgery was assessed in a retrospective review of the American quality assessment database (NSQIP). The same study group from Cleveland, Ohio, USA, published last year an analysis showing that preoperative anaemia negatively impacts postoperative outcome. In this study, they demonstrate that within 30 days following surgery, after adjusting for unbalanced covariates, blood transfusion was associated with increased morbidity but not mortality.

Transfused patients were matched with non-transfused patients using a propensity score that included 45 variables, most of them generally accepted to be relevant. Preoperative anaemia was among them. In addition, stratification for the number of received units was applied. Among 37,000 patients undergoing spine surgery, 900 had to be transfused, half and a quarter of them receiving one and two units of red blood cells (RBC), respectively. Even a single unit of RBC was associated with prolonged hospital stay and complications, and more transfused units were associated with more severe complications and longer hospital stay (among other outcomes). In the absence of randomised controlled trials, the methodology is acceptable and the results trustworthy.

– Thomas Frietsch

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