P118. A comparison of outcomes between obese and non-obese patients undergoing anterior cervical discectomy and fusion: a retrospective analysis of ten years of data from an urban academic institution

BACKGROUND CONTEXT Given the rising rates of obesity and its association with significant comorbidities, having a higher BMI has been linked to increased hospital costs and surgical complications. However, the impact of obesity on outcomes after anterior cervical discectomy and fusion (ACDF) remain inconclusive. Some studies show that obesity was not associated with lower improvement in patient-reported outcomes, operative time, blood loss, nor length of stay (LOS). However, other studies using national databases found that obese ACDF patients had higher complication rates, non-routine discharge, and costs. Thus, we aim to evaluate the risk of obesity on ACDF outcomes at a high-volume urban academic hospital. PURPOSE To compare perioperative factors, intraoperative factors, and clinical outcomes between obese (BMI≥30) and nonobese (BMI<30) patients who underwent ACDF. STUDY DESIGN/SETTING This was a retrospective study utilizing data from elective ACDFs performed between 2008-2019 at an urban, academic tertiary medical center. PATIENT SAMPLE A total of 1526 nonobese patients and 694 obese patients who underwent ACDF were identified from our institutional database. OUTCOME MEASURES Postoperative outcomes include required ICU stay, complication rates, nonhome discharge, 30- and 90-day readmission, and dysphagia. Multivariate linear regression analysis included LOS, total direct cost, and length of surgery. METHODS Using CPT codes 22551, 22552, and 22554, we identified patients aged 18 and older who underwent ACDF procedures. Patients undergoing the posterior approach, or non-elective ACDF excluded. They were then divided into two groups: nonobese and obese. Patient demographics, perioperative variables, and postoperative outcomes were compared using chi-squared analysis and student's t-test. Multivariate logistic and linear regression was performed controlling for age, sex, race, diabetes, hypertension, and segments fused. RESULTS There was a significant difference between the groups for age (nonobese: 52.7 years, obese: 51.5 years, p=0.025), race (p<0.001), Elixhauser Comorbidity Index scores (p<0.001), and ASA status (p<0.001). The obese group also had higher rates of diabetes (10.9% vs 22.8%, p<0.001), and hypertension (31.7% vs 46.3%, p <0.001). They also had longer operative times (p<0.001), but no significant difference was found for segments fused (p=0.950), estimated blood loss (p=0.091), or LOS (p=0.310). Multivariate linear regression showed that longer operative time was significantly associated with obesity (Coeff: 6.9 min, CI: 2.3-11.5, p=0.004), but not significantly associated with LOS (p=0.936) or total direct cost (p=0.543). Unadjusted chi-square analysis showed that the obese group had more patients requiring ICU stays (p=0.002) and 90-day readmission (p=0.047). Multivariate logistic regression analysis revealed that obese patients were at increased risk for requiring an ICU stay (OR=2.0, 95% CI 1.1-3.7, p=0.021). Obesity was not found to be associated with delayed extubation (p=0.226), patients with any postoperative complication (p=0.469), non-home discharge (p=0.526), 30- and 90-day readmission (p=0.155, p=0.804), or dysphagia (p=0.699). CONCLUSIONS Obese patients have significantly longer operative times, and higher risk for requiring an ICU stay even after controlling for significant demographic factors. These findings will allow providers to better manage resource utilization both intraoperatively, and postoperatively. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs. Given the rising rates of obesity and its association with significant comorbidities, having a higher BMI has been linked to increased hospital costs and surgical complications. However, the impact of obesity on outcomes after anterior cervical discectomy and fusion (ACDF) remain inconclusive. Some studies show that obesity was not associated with lower improvement in patient-reported outcomes, operative time, blood loss, nor length of stay (LOS). However, other studies using national databases found that obese ACDF patients had higher complication rates, non-routine discharge, and costs. Thus, we aim to evaluate the risk of obesity on ACDF outcomes at a high-volume urban academic hospital. To compare perioperative factors, intraoperative factors, and clinical outcomes between obese (BMI≥30) and nonobese (BMI<30) patients who underwent ACDF. This was a retrospective study utilizing data from elective ACDFs performed between 2008-2019 at an urban, academic tertiary medical center. A total of 1526 nonobese patients and 694 obese patients who underwent ACDF were identified from our institutional database. Postoperative outcomes include required ICU stay, complication rates, nonhome discharge, 30- and 90-day readmission, and dysphagia. Multivariate linear regression analysis included LOS, total direct cost, and length of surgery. Using CPT codes 22551, 22552, and 22554, we identified patients aged 18 and older who underwent ACDF procedures. Patients undergoing the posterior approach, or non-elective ACDF excluded. They were then divided into two groups: nonobese and obese. Patient demographics, perioperative variables, and postoperative outcomes were compared using chi-squared analysis and student's t-test. Multivariate logistic and linear regression was performed controlling for age, sex, race, diabetes, hypertension, and segments fused. There was a significant difference between the groups for age (nonobese: 52.7 years, obese: 51.5 years, p=0.025), race (p<0.001), Elixhauser Comorbidity Index scores (p<0.001), and ASA status (p<0.001). The obese group also had higher rates of diabetes (10.9% vs 22.8%, p<0.001), and hypertension (31.7% vs 46.3%, p <0.001). They also had longer operative times (p<0.001), but no significant difference was found for segments fused (p=0.950), estimated blood loss (p=0.091), or LOS (p=0.310). Multivariate linear regression showed that longer operative time was significantly associated with obesity (Coeff: 6.9 min, CI: 2.3-11.5, p=0.004), but not significantly associated with LOS (p=0.936) or total direct cost (p=0.543). Unadjusted chi-square analysis showed that the obese group had more patients requiring ICU stays (p=0.002) and 90-day readmission (p=0.047). Multivariate logistic regression analysis revealed that obese patients were at increased risk for requiring an ICU stay (OR=2.0, 95% CI 1.1-3.7, p=0.021). Obesity was not found to be associated with delayed extubation (p=0.226), patients with any postoperative complication (p=0.469), non-home discharge (p=0.526), 30- and 90-day readmission (p=0.155, p=0.804), or dysphagia (p=0.699). Obese patients have significantly longer operative times, and higher risk for requiring an ICU stay even after controlling for significant demographic factors. These findings will allow providers to better manage resource utilization both intraoperatively, and postoperatively.