Risk factors for adverse events after elective colorectal surgery: beware of blood transfusions.

Purpose of the present study is to analyze risk factors for adverse events after elective colorectal resection. A wide range of adverse events after elective colorectal surgery was reported, anastomotic leakage (AL) and related morbidity and mortality being the most feared ones. Clear definition of risk factors is crucial to limit the related mortality. Prospective, 1-year multicenter enrollment of 1546 elective colorectal resections with anastomosis. Endpoints were anastomotic leakage (AL), overall morbidity, major morbidity and mortality rates (ClinicalTrials.gov; Identifier: NCT03560180). AL rate was 4.92%. Overall morbidity, major morbidity and mortality rates were 30.20%, 9.76% and 1.29%, respectively. Intra- and/or postoperative blood transfusion(s) was the only variable independently influencing all the endpoints: Odds ratios (OR) were 8.15 for AL, 19.33 for overall morbidity, 10.17 for major morbidity and 3.70 for mortality); overall morbidity rates were also independently influenced by American Society of Anesthesiologists class III vs I-II and extra- vs intra-corporeal anastomosis (OR 1.57 and 1.49, respectively); major morbidity rates were also independently influenced by female vs male gender and by the length of the procedure (OR 0.60 and 1.004, respectively); mortality rates were also independently influenced by increasing age (OR 1.16). This study clearly identifies intra- and/or postoperative blood transfusion(s) as an independent risk factor for all adverse events after elective colorectal surgery.