Association of Preoperative Anemia With Postoperative Mortality in Neonates.

IMPORTANCE: Neonates undergoing noncardiac surgery are at risk for adverse outcomes. Preoperative anemia is a strong independent risk factor for postoperative mortality in adults. To our knowledge, this association has not been investigated in the neonatal population.

OBJECTIVE: To assess the association between preoperative anemia and postoperative mortality in neonates undergoing noncardiac surgery in a large sample of US hospitals.

DESIGN, SETTING, AND PARTICIPANTS: Using data from the 2012 and 2013 pediatric databases of the American College of Surgeons National Surgical Quality Improvement Program, we conducted a retrospective study of neonates undergoing noncardiac surgery. Analysis of the data took place between June 2015 and December 2015. All neonates (0-30 days old) with a recorded preoperative hematocrit value were included.

EXPOSURES: Anemia defined as hematocrit level of less than 40%.

MAIN OUTCOMES AND MEASURES: Receiver operating characteristics analysis was used to assess the association between preoperative hematocrit and mortality, and the Youden J Index was used to determine the specific hematocrit cutoff point to define anemia in the neonatal population. Demographic and postoperative outcomes variables were compared between anemic and nonanemic neonates. Univariate and multivariable logistic regression analyses were used to determine factors associated with postoperative neonatal mortality. An external validation was performed using the 2014 American College of Surgeons National Surgical Quality Improvement Program database.

RESULTS: Neonates accounted for 2764 children (6%) in the 2012-2013 American College of Surgeons National Surgical Quality Improvement Program databases. Neonates inlcuded in the study were predominately male (64.5%), white (66.3%), and term (69.9% greater than 36 weeks' gestation) and weighed more than 2 kg (85.0%). Postoperative in-hospital mortality was 3.4% in neonates and 0.6% in all age groups (0-18 years). A preoperative hematocrit level of less than 40% was the optimal cutoff (Youden) to predict in-hospital mortality. Multivariable regression analysis demonstrated that preoperative anemia is an independent risk factor for mortality (OR, 2.62; 95% CI, 1.51-4.57) in neonates. The prevalence of postoperative in-hospital mortality was significantly higher in neonates with a preoperative hematocrit level less than 40%; being 7.5% (95% CI, 1%-10%) vs 1.4% (95% CI, 0%-4%) for preoperative hematocrit levels 40%, or greater. The relationship between anemia and in-hospital mortality was confirmed in our validation cohort (National Surgical Quality Improvement Program 2014).

CONCLUSIONS AND RELEVANCE: To our knowledge, this is the first study to define the incidence of preoperative anemia in neonates, the incidence of postoperative in-hospital mortality in neonates, and the association between preoperative anemia and postoperative mortality in US hospitals. Timely diagnosis, prevention, and appropriate treatment of preoperative anemia in neonates might improve survival.