Relationship between the Charlson Comorbidity Index and cost of treating hip fractures: implications for bundled payment

BACKGROUND: The aim of this study is to investigate how the Charlson Comorbidity Index (CCI) scores contribute to increased length of stay (LOS) and healthcare costs in hip fracture patients. MATERIALS AND METHODS: Through retrospective analysis at an Urban level I trauma center, charts for all patients over the age of 60 years who presented with low-energy hip fracture were evaluated. 615 patients who underwent operative fixation of hip fracture or hemiarthroplasty secondary to hip fracture were identified using Current Procedural Terminology (CPT) codes search and included in the study. Data was collected on patient demographics, medical comorbidities, and hospitalization length; from this, the CCI score and the cost to the institution (with an average cost/day of inpatient stay of $4,530) were calculated. RESULTS: Multivariate linear regression analysis modeled the length of stay as a function of CCI score. Each unit increase in the CCI score corresponded to an increase in length of hospital stay and hospital costs incurred [effect size = 0.21; (0.0434–0.381); p = 0.014]. Patients with a CCI score of 2 (compared to a baseline CCI score of 0), on average, stayed 1.92 extra days in the hospital, and incurred $8,697.60 extra costs. CONCLUSIONS: The CCI score is associated with length of stay and hospital costs incurred following treatment for hip fracture. The CCI score may be a useful tool for risk assessment in bundled payment plans. LEVEL OF EVIDENCE: Level III.