Prediction of Severe Postoperative Anemia After Low-Risk Cesarean Delivery [ID: 1370554

Abstract

INTRODUCTION: Postoperative laboratory tests after cesarean delivery are routinely performed. With an accurate prediction of individuals at an increased risk of severe postoperative anemia, we may safely reduce the number of routine postoperative laboratory tests. We aimed to develop a scoring system that predicts severe postoperative anemia (hemoglobin less than 7.0 g/dL) after low-risk cesarean delivery. METHODS: This was a retrospective case–control study. Individuals with placental abruption, placenta accrete, placenta previa, preeclampsia, HELLP, and blood loss greater than or equal to 1,000 mL were excluded. Predictive variables with P value less than .05 in simple and multivariate logistic regression models were used in the scoring system. Weighted points based on the logarithm of odds ratio in the multivariate logistic regression model were allocated to each factor, and the score was calculated as a summation of those points. Our IRB approved this analysis. RESULTS: Of 1,955 individuals analyzed, 35 (1.8%) had severe postoperative anemia. The predictive factors included preoperative Hb less than or equal to 10.0 g/dL (4.0 points), blood loss greater than or equal to 816 mL (1.0 point), body mass index less than or equal to 30.5 kg/m2 (1.0 point), and preoperative platelet greater than or equal to 194×1,000/mL (1.0 point). The area under a curve of the model was 0.92 (95% CI 0.88–0.97). Using score 3.0 as a cutoff, sensitivity, specificity, and positive and negative predictive values were 91.4%, 83.9%, 9.4%, and 99.8%. CONCLUSION: We created a scoring system for severe postoperative anemia with high discriminative ability.