Efficacy of the modified Frailty Index and the modified Charlson Comorbidity Index in predicting complications in patients undergoing operative management of proximal humerus fracture

Abstract

Background: Comorbidity indices such as the 5-factor modified Frailty Index (mFI-5) and modified Charlson Comorbidity Index (mCCI) are widely used in outcomes research.

Methods: A total of 3893 patients who underwent total shoulder arthroplasty (n=975), hemiarthroplasty (n=495), or open reduction and internal fixation (n=2423) for the treatment of proximal humerus fracture from 2005-2017 were identified from the National Surgical Quality Improvement Program database. Data regarding demographics, comorbidities, American Society of Anesthesiologists class, and postoperative complications were collected, and the mFI-5 and mCCI were calculated for each case. Multivariate logistic regression models and receiver operating characteristic curve analyses were performed.

Results: The patient population had a mean age of 68.0 ± 13.2 years, body mass index of 29.1 ± 8.1 and mean operative time of 119.9 ± 55.5 minutes. The most common complications within this cohort were extended length of stay (4 days or more) (1085/3893; 27.87%), transfusion (377/3893; 9.68%), unplanned reoperation (97/3893; 2.49%), urinary tract infection (43/3893; 1.10%), death (42/3893; 1.08%), and deep vein thrombosis (40/3893; 1.03%). After accounting for patient demographics, the mFI-5 (odds ratio [OR] = 1.105, P < .001) and mCCI (OR = 1.063, P < .001) were significantly associated with incidence of any adverse event. Both comorbidity indices had low positive predictive value and high negative predictive value for all adverse events.

Conclusion: The comorbidity indices mCCI and mFI-5 are both strongly associated with adverse events but have moderate ability to predict complications following surgical treatment of proximal humerus fractures.

Keywords: American Society of Anesthesiologists classification; Charlson Comorbidity Index; Frailty Index; Proximal humerus fracture; adverse events; open reduction internal fixation; reverse total shoulder arthroplasty.