A Clinically Applicable Prediction Model for the Risk of Transfusion in Women Undergoing Myomectomy.

Abstract

OBJECTIVE\nWe sought to identify variables independently associated with intra/postoperative blood transfusion at the time of myomectomy. We further hoped to develop an accurate prediction model using preoperative variables to categorize an individual s risk of transfusion during myomectomy.\n\n\nDESIGN\nCase-control study SETTING: Not applicable to this study using the American College of Surgeons (ACS) NSQIP database.\n\n\nPATIENTS\nWomen who underwent an open/abdominal or laparoscopic (robotic or conventional) myomectomy between 2014 and 2017 at participating ACS-NSQIP sites.\n\n\nINTERVENTION\nThe primary dependent variable was occurrence of intra/postoperative bleeding requiring blood transfusion. Patient demographics, clinical characteristics, preoperative comorbidities, intraoperative variables, and additional 30-day postoperative outcomes were compared at the biivariable level. For prediction model development, only variables that can reasonably known before surgery were used in order to allow for a clinically applicable prediction model. For prediction model development, only variables that can reasonably known before surgery were included. Variables associated with intra/postoperative bleeding were entered into two separate multivariable logistic regression models. Validation of our prediction model was performed internally using 250 bootstrapped iterations of 50% sub-samples drawn from the overall population of myomectomy cases from the ACS-NSQIP database.\n\n\nMEASUREMENTS AND MAIN RESULTS\nWe identified 6,387 myomectomies performed during the defined study period. The most common race in our population was Black/African-American (45.7%) and the majority of patients (57.5%) received an open/abdominal route of myomectomy. Six hundred and twenty-three myomectomy patients (9.8%) experienced intraoperative/postoperative bleeding with a need for blood transfusion. At the biivariable level we identified several variables independently associated with the need for blood transfusion at the time of myomectomy. In using only those variables that can be reasonably known prior to surgery to develop our prediction model, additional multivariable logistic regression elucidated Black race, need for preoperative transfusion, planned abdominal/open route of surgery, and preoperative hematocrit as independently associated with blood transfusion.\n\n\nCONCLUSION\nWe identified a number of perioperative variables associated with intraoperative or postoperative bleeding requiring blood transfusion at the time of myomectomy. We subsequently created a model that accurately predicts individual bleeding risk from myomectomy using variables that are reasonably apparent preoperatively. Making this prediction model clinically available to gynecologic surgeons will serve to improve the care of women undergoing myomectomy.