113. Impact of iron deficiency anemia on postoperative outcomes of thoracolumbar spinal fusion (≥2-level) on patients with adult spinal deformity with minimum two-year follow-up surveillance

Abstract

BACKGROUND CONTEXT Iron deficiency anemia (IDA) is a common hematological disorder and cause of low hemoglobin. Preoperative anemia has been shown to increase the risk of adverse outcomes after posterior cervical fusion and other spinal surgery. The need for a transfusion during lumbar fusion has been shown to increase the length of stay. The impact of IDA on outcomes after spinal fusion for ASD is unknown. PURPOSE This study sought to compare outcomes and complication rates between ASD patients with and without IDA undergoing 2+ level spinal fusion. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE The New York State Statewide Planning and Research Cooperative System (NYS SPARCS) was queried from 2009-2011 to identify all patients undergoing 2+ level spinal fusion for ASD with two-year follow-up. OUTCOME MEASURES Two-year rates of medical and surgical complications as well as readmissions, reoperations and mortality. METHODS NY SPARCS was queried from 2009-11 to identify all patients undergoing 2-level thoracolumbar spinal fusion (primary and revision) for ASD with 2-year follow-up. Patients were then stratified by the presence (IDA) or absence (no-IDA) of IDA. IDA and no-IDA were 1:1 propensity score-matched based on age, sex and obesity. Univariate analysis compared demographics, hospital parameters, and rates of adverse outcomes. Multivariate binary logistic regression was used to identify independent predictors of adverse outcomes. RESULTS A total of 524 patients (262 IDA and 262 no-IDA) were identified. There was no difference in age (56.8 vs 56.8 years), sex (79.8% vs 79.8% female), or obesity (13.0% vs 13.0%), all p=1.0. IDA patients had higher hospital cost ($95, 673 vs $59,537) and LOS (6.0 vs 4.0 days), all p < 0.001. IDA patients experienced higher rates of overall surgical complications (50.4% vs 23.7%, p < 0.001), wound complications (3.4% vs 0.4%, p=0.011), and blood transfusion (10.3% vs 6.5%, p <0.001). There was no difference in the rate of overall medical complications. IDA and no-IDA had comparable rates of readmission (8.0% vs 13.0%, p=0.064), though IDA had lower rates of reoperation (7.6% vs 13.0%, p=0.044). There was no mortality in either cohort. IDA independently was associated with wound complications (OR=10.6, p=0.028), blood transfusion (OR=3.9, p <0.001), and surgical complications (OR=3.5, p <0.001). CONCLUSIONS Baseline IDA was predictive of increased wound complications, postoperative blood transfusion and overall surgical complications following ASD surgery. This data can be used to better optimize and risk-stratify patients prior to surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Iron deficiency anemia (IDA) is a common hematological disorder and cause of low hemoglobin. Preoperative anemia has been shown to increase the risk of adverse outcomes after posterior cervical fusion and other spinal surgery. The need for a transfusion during lumbar fusion has been shown to increase the length of stay. The impact of IDA on outcomes after spinal fusion for ASD is unknown. This study sought to compare outcomes and complication rates between ASD patients with and without IDA undergoing 2+ level spinal fusion. Retrospective review. The New York State Statewide Planning and Research Cooperative System (NYS SPARCS) was queried from 2009-2011 to identify all patients undergoing 2+ level spinal fusion for ASD with two-year follow-up. Two-year rates of medical and surgical complications as well as readmissions, reoperations and mortality. NY SPARCS was queried from 2009-11 to identify all patients undergoing 2-level thoracolumbar spinal fusion (primary and revision) for ASD with 2-year follow-up. Patients were then stratified by the presence (IDA) or absence (no-IDA) of IDA. IDA and no-IDA were 1:1 propensity score-matched based on age, sex and obesity. Univariate analysis compared demographics, hospital parameters, and rates of adverse outcomes. Multivariate binary logistic regression was used to identify independent predictors of adverse outcomes. A total of 524 patients (262 IDA and 262 no-IDA) were identified. There was no difference in age (56.8 vs 56.8 years), sex (79.8% vs 79.8% female), or obesity (13.0% vs 13.0%), all p=1.0. IDA patients had higher hospital cost ($95, 673 vs $59,537) and LOS (6.0 vs 4.0 days), all p < 0.001. IDA patients experienced higher rates of overall surgical complications (50.4% vs 23.7%, p < 0.001), wound complications (3.4% vs 0.4%, p=0.011), and blood transfusion (10.3% vs 6.5%, p <0.001). There was no difference in the rate of overall medical complications. IDA and no-IDA had comparable rates of readmission (8.0% vs 13.0%, p=0.064), though IDA had lower rates of reoperation (7.6% vs 13.0%, p=0.044). There was no mortality in either cohort. IDA independently was associated with wound complications (OR=10.6, p=0.028), blood transfusion (OR=3.9, p <0.001), and surgical complications (OR=3.5, p <0.001). Baseline IDA was predictive of increased wound complications, postoperative blood transfusion and overall surgical complications following ASD surgery. This data can be used to better optimize and risk-stratify patients prior to surgery.