Early identification of covid-19 patients susceptible to rapid deterioration using the rothman index

INTRODUCTION: COVID-19 patients have a recognized susceptibility to rapid and severe deterioration Early identification of patients at risk of deterioration is a clinical challenge Characteristics associated with COVID-19 risk, including age and comorbidity, are crude predictors of ICU utilization and mortality risk Real-time predictive models may aid in determining appropriate patient placement and care plans We assess whether the Rothman Index (RI) acuity model can predict mortality risk and distinguish between high and low-risk COVID-19 patients at the time of admission METHODS: We conducted an IRB approved study of 1,453 COVID-19 patients discharged from Yale New Haven Health System's New Haven, Bridgeport, and Greenwich hospitals from 4/1/2020 - 4/28/2020 The initial RI score on admission was used to predict risk of ICU utilization, mechanical ventilation, and in-hospital mortality, and corresponding AUC values were computed We also compared patient age, Charlson Comorbidity Index, and RI on admission as indicators of in-hospital mortality risk and calculated predictive performance for each Precision and recall curves for mortality prediction using initial RI thresholds were determined and performance at selected operating points evaluated RESULTS: As a direct measure of acuity the RI was a substantially better predictor of COVID-19 in-hospital mortality than age or comorbidity (AUC values of 0 87, 0 78, 0 70, respectively) The RI computed at the time of admission provided a high degree of discrimination to differentiate COVID-19 populations into high and low-risk groups At selected RI cut-points, the high-risk segment constituted 18- 27% of COVID-19 patients with a mortality rate of 39-46% The low-risk segment constituted 48%-58% of patients with a mortality rate of 1%-3% CONCLUSIONS: COVID-19 patients exhibit elevated mortality compared to non-COVID-19 patients and may be subject to rapid deterioration following hospital admission The RI is an excellent predictor to stratify COVID-19 patient risk at the time of admission In particular we find that COVID-19 patients who present with raised but unremarkable acuity may be flagged as high risk for physiological deterioration This can aid providers in aligning level of care decisions at admission with hospital and ICU capacity constraints