Enhancing the American College of Surgeons NSQIP Surgical Risk Calculator to Predict Geriatric Outcomes

Abstract Background The ACS NSQIP Surgical Risk Calculator (SRC) plays an important role in risk prediction and decision-making. We sought to 1) enhance the existing ACS NSQIP SRC with functionality to predict geriatric-specific outcomes and 2) assess the predictive value of geriatric-specific risk factors by comparing performance in outcome prediction using the traditional ACS NSQIP SRC versus models that also included geriatric risk factors. Study Design Data were collected from 21 ACS NSQIP Geriatric Surgery Pilot Project (GSPP) hospitals between 2014-2017. Hierarchical regression models predicted four postoperative geriatric outcomes (i.e. pressure ulcer, delirium, new mobility aid use, and functional decline) using the traditional 21-variable ACS NSQIP SRC models and 27-variable models that included six geriatric risk factors (i.e. living situation, fall history, mobility aid use, cognitive impairment, surrogate-signed consent, and palliative care on admission). Results Data from 38,048 patients ages ≥ 65 undergoing 197 unique operations across 10 surgical subspecialties were used. Stable model discrimination and calibration between developmental and validation datasets confirmed predictive validity. Models with and without geriatric risk factors demonstrated excellent performance (c-statistics > 0.8) with inclusion of geriatric risk factors improving performance. Of the 21 ACS NSQIP variables, Current Procedural Terminology (CPT) code, chronic obstructive pulmonary disease (COPD), age, functional dependence, sex, disseminated cancer, diabetes, and sepsis were the strongest risk predictors, while impaired cognition, fall history, and mobility aid use were the strongest geriatric predictors. Conclusion The ACS NSQIP SRC can predict four unique outcomes germane to geriatric surgical patients, with improvement of predictive capability after accounting for geriatric risk factors. Augmentation of ACS NSQIP SRC may enhance shared decision-making to improve the quality of surgical care in older adults.