P75. Average costs, length of stay, and 30- and 90-day readmissions in obese and morbidly obese patients who undergo lumbar spine fusion

Abstract

BACKGROUND CONTEXT Approximately 40% of the United States population is obese, presenting daily challenges to the orthopedic surgeon. Recent studies have shown that obesity is associated with increased complication rates, costs, and readmission rates following lumbar spine fusion, but no granular data exists on how each increasing level of BMI impacts these variables. PURPOSE The purpose of this study is to analyze differences in costs, length of stay, and 30- and 90-day readmission rates in obese and morbidly obese patients. STUDY DESIGN/SETTING A retrospective cohort study was conducted using the National Readmissions Database (NRD) from 2013-2016. PATIENT SAMPLE A total of 56,076 patients with BMI levels of 30-59.9 who underwent primary single and multi-level lumbar spine fusion between the years of 2013-2016. OUTCOME MEASURES Total cost of primary hospital admission, length of stay, and 30- and 90-day readmission rates. METHODS Using ICD-9 and ICD-10 codes, 56,076 patients with BMI levels of 30-59.9 who underwent primary single and multi-level lumbar spine fusion were identified. Patients were grouped into BMI categories of 30-34.9 (group 1), 35-39.9 (group 2), 40-44.9 (group 3), 45-49.9 (group 4), and 50-59.9 (group 5), and total 30- and 90-day readmissions data were collected. Statistical analysis was conducted in R. Kruskal-Wallis tests with Dunn's pairwise comparisons were performed to analyze differences in costs, length of stay, and 30- and 90-day readmission rates between BMI groups. RESULTS Average total cost of admission was $177,153, $176,782, $176,798, $176,698, and $251,723 in groups 1 through 5, respectively. Compared with groups 1-4, group 5 had significantly higher total cost of admission (p CONCLUSIONS Despite an upward trend in 30- and 90-day readmission rates with increasing BMI, the majority of pairwise comparisons between BMI groups showed no statistical significance. Length of stay significantly increased with increased BMI levels. More research is needed to investigate the exact etiologies of differences in readmission rates and length of stay between BMI groups to ensure appropriate risk stratification and postoperative planning. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.