A Prognostic Tool for COVID-19 Decision Support: The Intermountain Risk Score Predicts Major Adverse Health Events in Patients Positive for COVID-19

Abstract

Background: As the COVID-19 pandemic evolves, stratifying risk is increasingly important. The Intermountain Risk Score (IMRS) uses the complete blood count (CBC) and basic metabolic profile (BMP) as a first-line predictor of mortality and is widely validated. We hypothesized that IMRS predicts COVID-19 outcomes. \n \nMethods: Intermountain Healthcare patients aged ≥18 years were evaluated if they had CBC and BMP measured in 2019 and tested positive for COVID-19 in 2020. Viral RNA testing for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was conducted March 3 through November 2, 2020. IMRS used published sex-specific weightings and associations were evaluated for the composite of COVID-19 hospitalization or mortality. \n \nFindings: Among 3,883 patients, 8.2% were hospitalized, 1.6% died. Subjects with low, mild, moderate, and high-risk IMRS had the composite endpoint in 3.5% (52/1,502), 8.6% (108/1,256), 15.5% (152/979), and 28.1% (41/146), respectively. Versus low-risk, subjects in mild, moderate, and high-risk groups had HR=2.33 (95% CI: 1.67, 3.24), HR=4.01 (CI: 2.93, 5.50), and HR=8.34 (CI: 5.54, 12.57), respectively. Subjects aged <60 years had HR=3.06 (CI: 2.01, 4.65) and HR=7.38 (CI: 3.14, 17.34) for moderate and high versus low-risk, respectively; those ≥60 years had HR=1.95 (CI: 0.99, 3.86) and HR=3.40 (CI: 1.63, 7.07). In multivariable analyses, IMRS was independently predictive but was shown to capture substantial risk variation of comorbidities. \n \nInterpretation: IMRS, a simple risk score using very basic laboratory results, predicted COVID-19 hospitalization and mortality. This included important abilities to identify risk in younger adults with few diagnosed comorbidities and to predict risk prior to SARS-CoV-2 infection. \n \nFunding Statement: This study was funded by internal Intermountain departmental funds. \n \nDeclaration of Interests: BDH, HTM, BSR, and JLA are inventors of clinical decision tools that are licensed to CareCentra and Alluceo. BDH is the PI of grants related to clinical decision tools that were funded by Intermountain Healthcare’s Foundry innovation program, the Intermountain Research and Medical Foundation, CareCentra, GlaxoSmithKline, and AstraZeneca. BDH is a member of the scientific advisory board of Labme.ai. KUK is PI of and BDH a co-investigator of a grant funded by the Patient- Centered Outcomes Research Institute (PCORI). IDP was supported by a grant from the National Institute of General Medical Sciences (K23GM129661). Outside the current work, IDP has received grant support from the National Institutes of Health, Centers for Disease Control, Janssen Pharmaceuticals, and Immunexpress Inc and funding to his institution from Regeneron Pharmaceuticals. The authors have no other potential conflicts of interest to report. \n \nEthics Approval Statement: This study was approved as a data-only historical records review study with a waiver of consent by the Intermountain Healthcare Institutional Review Board.