509 Data-Driven Preoperative Hemoglobin Strata that Maximize the Likelihood of Blood Transfusion following Single-Level Lumbar Fusion Are Also Predictive of Major Complications and Deep Infections

Abstract

INTRODUCTION: Optimizing patients undergoing single-level lumbar spine fusion helps reduce the use of blood transfusions which are associated with an increased risk of major complications and deep infection. Current hemoglobin thresholds for anemia severity were published in 1968 and are not surgery specific. METHODS: A retrospective cohort analysis was performed using a national database to identify patients undergoing primary single-level lumbar fusion with recorded hemoglobin values 30 days before surgery. Stratum-specific likelihood ratio (SSLR) analysis defined sex-based hemoglobin strata associated with the risk of 90-day postoperative blood transfusion. Each stratum was propensity-score matched to the highest identified hemoglobin stratum. Incidence rates and risk of 90-day major complications and 2-year deep infection between strata were observed. RESULTS: For 90-day blood transfusion, SSLR identified three female [Strata, Likelihood ratio (5.0-10.9, 2.41; 11.0-12.4, 1.35; 12.5-17.0, 0.78)] and three male hemoglobin strata (5.0-11.9, 2.95; 12.0-13.4, 1.46; 13.5-13.9, 0.71). Increased risk of 90-day major complications was associated with two female (11.0-12.4 [RR: 1.52; p < 0.001], 5.0-10.9 [RR: 3.40; p < 0.001]) and one male stratum (5.0-11.9 [RR: 2.02; p < 0.001]). Increased risk of 2-year deep infection was associated with one female (5.0-10.9 [RR: 3.67; p < 0.001]) and one male stratum (5.0-11.9 [RR: 2.11; p = 0.005]). CONCLUSIONS: SSLR analysis established single-level lumbar fusion-specific hemoglobin strata that maximize the likelihood of 90-day blood transfusions and predict the risk of 90-day major complication and 2-year deep infection. We recommend using these thresholds during preoperative optimization, noting the sequential increase in risk of complications starting with a hemoglobin of less than 13.5 in males and 12.5 in females.