BackgroundThe aim of this study is to define the cost of rib fracture hospitalization by single, multiple, and flail type using a nationally representative sample. MethodsThe national inpatient sample (NIS) was used to identify patients with a primary diagnosis of rib fracture hospitalization 2007-2016. International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) codes were used to characterize patients as having single, multiple, or flail chest rib fractures. Patients with only trauma related diagnosis groups (DRG) at the time discharge were included in the final sample. The cost of hospitalization was obtained by converting reported charges into cost using the all-payer inpatient cost-to-charge ratio (CCR) for all hospitals in the NIS data. The log of cost was modeled using multivariate linear regression. The rib fracture type was the primary predictor in the model. ResultsThere were 373,053 rib fracture admissions during 2007-2016. The average cost per hospitalization was $10,169 (95%Confidence Interval [CI]: 9,942–10,395), which translated into a national expenditure of $3.64 billion over 10 years. The cost of rib fracture hospitalization increased from $209 million in 2007 to $469 million in 2016. Compared to single rib fracture patients, the cost of hospitalization for multiple rib fractures and flail chest was 3% (p = 0.001) and 5% (p=0.02) higher, respectively. Higher injury severity score, total number of body regions injured and longer length of stay were associated with higher rib fracture hospitalization cost. ConclusionsRib fractures affect ~22,000-45,000 people per year in the United States. The cost of rib fractures is over $469 million per year and is increasing over time. Multiple rib fractures and flail chest rib fractures are associated with increased cost. Pathways to improve care in patients with rib fractures should consider the cost of treatment.