Medicaid insurance is associated with treatment disparities for proximal humerus fractures in a national database analysis

Background: Proximal humerus fractures (PHFs) are the third most common type of fragility fracture in the elderly and are increasing in incidence. Disparities in treatment type, time to surgery (TTS), and complications based upon insurance type have been identified for other orthopedic conditions. Given the incidence and burden of PHFs, we sought to evaluate if insurance type was associated with treat-ment received, TTS, and complications in the treatment of PHFs.Methods: We used PearlDiver, a national administrative claims database that consists of 122 million patient records. Patients diagnosed with an isolated PHF between 2010 and 2019 were identified by International Classification of Diseases, Ninth and Tenth Revision diag-nostic codes and stratified by insurance type (Medicaid, private, or Medicare). Outcomes evaluated were rate of surgery within 3 months of diagnosis with open reduction and internal fixation, hemiarthroplasty, or reverse shoulder arthroplasty; average TTS; 90-day read-missions and medical postoperative complications (deep vein thrombosis, urinary tract infection, pneumonia, sepsis, acute respiratory failure, cerebrovascular event, and acute renal failure); and 1-year surgical postoperative complications (stiffness, noninfectious wound complications, dislocation, and infection). Multivariable logistic regressions adjusting for age, sex, and Elixhauser comorbidity index were utilized to determine the association between insurance type and surgery rate/complications.Results: We included 245,396 patients for analysis. Fourteen percent of Medicaid patients (1789/12,498) underwent surgery compared to 17% (25,347/149,830) of privately insured patients and 16% (13,305/83,068) of Medicare patients (pairwise, P < .001). TTS (Medicaid: 11.7 days, private: 10.6 days [P < .001]; Medicare: 10.7 days [P 1/4 .003]) varied by insurance type. Private or Medicare -insured patients were less likely to be readmitted (adjusted odds ratio: 0.77 [95% confidence interval (CI): 0.63-0.93] for private vs. Medicaid and 0.71 [95% CI: 0.59-0.88] for Medicare vs. Medicaid) and experienced fewer 90-day postoperative complications (adjusted odds ratio: 0.73 [95% CI: 0.62-0.85] for private vs. Medicaid, 0.65 [95% CI: 0.55-0.77] for Medicare vs. Medicaid), such as acute renal failure. TTS was also associated with differing rates of readmissions and complications.Conclusion: There are differences in rates of surgery, TTS, and complications after PHFs based on insurance type, representing oppor-tunities for quality improvement initiatives. Potential methods to address these disparities include implementing standardized PHF pro-tocols and/or reimbursement models and quality metrics that reward equitable treatment. Further research and policy adaptations should be incorporated to decrease barriers that patients face and minimize health care inequities seen in the treatment of PHFs based on in-surance type.Level of evidence: Level III; Retrospective Cohort Comparison Using Large Database; Prognosis Study & COPY; 2022 The Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).