preventing resulting morbidities including pneumothorax and pneumonia. Recent literature suggests that many patients with isolated rib fracture may be discharged from the ED. The objective of this study was to determine ED disposition of patients diagnosed with rib fracture in United States (US) and explore select clinical and demographic characteristics. We hypothesized that the proportion of patients with rib fracture admitted from the ED would vary based upon the location and characteristics of the institution providing care.Methods: This was a retrospective, observational cohort study analyzing four years of data (2006)(2007)(2008)(2009) from the Nationwide Emergency Department Sample (NEDS), a part of the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. The NEDS uses a stratified, multi-stage sample that provides national estimates of ED visits each year in the US. The NEDS contains approximately 28 million records per year from over 950 EDs in 28 states. ICD-9-CM diagnosis codes were used to abstract cases of rib fractures. Cases with codes between 807.00 and 807.09 (fracture of rib(s), sternum, larynx, and trachea; fifth digit represents the number of ribs fractured) that were present in the primary diagnosis field were used. The following demographic and clinical variables were examined for visits that resulted in discharge from the ED as well as admission to the hospital: total number of ED visits, age, sex, disposition, hospital region, trauma designation, hospital teaching status and total charges. Weighted estimates and unbiased standard errors were calculated using SAS-Callable SUDAAN.Results: Between 2006 and 2009, there were 844,383 ED visits resulting in a primary diagnosis of rib fracture. Of these visits, 680,574 (80%) resulted in discharge from the ED and 136,727 (16%) resulted in hospital admission. The mean age of the sample was 58 years and 59% of visits were from males. The majority of visits occurred at non-trauma centers (68%) and metropolitan non-teaching hospitals (47%) in the southern region (37%) of the US. A greater percentage of visits that occurred at trauma centers ended in admission (32%) compared to those at non-trauma centers (11%). Additionally, more visits occurred at teaching hospitals (25%) versus non-teaching hospitals (13%). ED disposition for rib fracture visits also varied based upon region. Visits in the western region were most likely to result in admission (19%), whereas those in the southern region were least likely end in admission (14%). Common principal procedures performed were traction, splints and other wound care (22%), chest x-ray (7%) and suture of skin and subcutaneous tissue (4%). The total charge for ED visits was $1,360,388,292 and $1,602,820,036 for visits requiring admission.Conclusions: The disposition of patients diagnosed with rib fracture may be affected by institution trauma designation, teaching status and region. Recent advances in treatment guidelines for rib fracture may contribute to this variability. Whil...