LAUSR

OBJECTIVE To elucidate risk factors for 90-day readmission in ACDF for small, medium, and large hospitals respectively. To assess differences in length of stay, charges, and complication rates across hospitals of different size. METHODS This was a retrospective analysis utilizing elective, single-level ACDF data from 2016-2018 in the HCUP Nationwide Readmissions Database (NRD). Elective single-level ACDF cases were stratified into three groups by hospital bed size (small, medium, and large). All-cause complication rates, mean charges, length of stay, and 90-day readmission rates were compared across hospital size. Frequencies of specific comorbidities were compared between readmitted and non-readmitted patients for each hospital size. Comorbidities significant on univariate analysis were evaluated as independent risk factors for 90-day readmission for each hospital size using multivariate regression. RESULTS The overall 90-day readmission rate was 6.43% in 36,794 total patients, and the rates for small, medium, and large hospitals were 6.25%, 6.28%, and 6.56% respectively (p=0.537). Length of stay increased significantly with hospital size (p<0.001), and small hospitals had the lowest charges (p<0.001). While different independent predictors of 90-day readmission were identified for each hospital size, Cardiac Arrhythmia, Chronic Pulmonary Disease, Neurological Disorders, and Rheumatic Disease were identified as risk factors for hospitals of all sizes. CONCLUSIONS Hospital size is a determining factor for charges and length of stay associated with elective single-level ACDF. Variation in risk factors for readmission exist across hospital size in context of similar 90-day readmission rates.