Comparative Analysis of 3 Mortality Risk Prediction Tools: Almelo Hip Fracture (AHFS), Revised Cardiac Risk Index (RCRI), and American College of Surgery (ACS)-National Surgical Quality Improvement Program (NSQIP) Surgical Risk Calculator (Preprint)

Abstract

Hip fractures are common injuries among the elderly population and could impose serious health care burden. Recent estimation projects 1.5 million people are affected worldwide (Nijmeijer). Post-surgical complications including death remain as significant healthcare challenges and the estimated mortality has been reported 13.3% at its highest in the first 30 days post-operative period. (Nijmeijer et al and Hu et al). In order to improve surgical outcomes, numerous risk assessment tools have been developed over the last several decades to predict mortality risk based on consideration of several variables. Two of the most commonly used 30-day mortality risk calculators for all surgeries including orthopedic surgeries are the National Surgical Quality Improvement Program (NSQIP) Surgical Risk Calculator approved by the American College of Surgeons and the Revised Cardiac Risk Index (RCRI) approved by American College of Cardiology (ACC) /American Heart Association (AHA).

The study site is Overlook Medical Center (OMC), New Jersey, which is a 1106-bed community hospital where the hip fracture team, which comprises of orthopedists, internists, anesthesiologists, palliative care experts, nursing, physical therapists, social workers, case managers, etc. was established in 2015. We have been using the NSQIP surgical risk calculator and RCRI as tools to predict 30-day mortality to help optimize/make decisions regarding surgery and patient care. The aim of this study is to determine if AHFS would be a better risk calculator for 30 day-post hip surgery mortality when being compared to the NSQIP surgical risk calculator and RCRI risk calculator based on this retrospective study on the patients who underwent surgery following hip fracture.

We conducted a retrospective study of patients who were admitted to Overlook Medical Center, NJ, USA with a primary diagnosis of a low-energy hip fracture and subsequently underwent surgery from January 01, 2019 to December 31, 2020. We excluded non-surgically treated patients and high-energy traumatic fractures. The fractures were classified according to location(trochanteric, intertrochanteric etc.) and the type of surgery they had (CPT codes: 27236 – Open treatment of femoral fracture, proximal and , neck, internal fixation or prosthetic replacement; 27244 – treatment of intertrochanteric, peritrochanteric, or subtrochanteric femoral fracture; with plate/screw type implant, with or without cerclage; 27245 – treatment of intertrochanteric, peritrochanteric or subtrochanteric; intermedullary implant, with or without interlocking screws/with or without cerclage.

With all data and results considered, our study demonstrates that no perfect scoring system exists. Currently accepted models all possess inherent flaws; providers should consider the scores generated by each tool in the context of the clinical situation. Among the three tools examined in our study, we found the AHFS is likely the best at predicting mortality in high-risk patients (Almelo score >= 12) as higher scores were consistently associated with a higher percentage of mortality.

Given the results of our study, we are considering transitioning to the Almelo Hip Fracture Score as the primary preoperative risk assessment tool for hip fracture patients admitted to Overlook Medical Center. As previously mentioned, this population commonly consists of patients at increased risk of perioperative complications and therefore the AHFS may be a more appropriate stratification tool compared to the RCRI.