Predicting severe outcomes in Covid-19 related illness using only patient demographics, comorbidities and symptoms

Abstract

Objective: Development of a risk-stratification model to predict severe Covid-19 related illness, using only presenting symptoms, comorbidities and demographic data.

Materials and methods: We performed a case-control study with cases being those with severe disease, defined as ICU admission, mechanical ventilation, death or discharge to hospice, and controls being those with non-severe disease. Predictor variables included patient demographics, symptoms and past medical history. Participants were 556 patients with laboratory confirmed Covid-19 and were included consecutively after presenting to the emergency department at a tertiary care center from March 1, 2020 to April 21, 2020 RESULTS: Most common symptoms included cough (82%), dyspnea (75%), and fever/chills (77%), with 96% reporting at least one of these. Multivariable logistic regression analysis found that increasing age (adjusted odds ratio [OR], 1.05; 95% confidence interval [CI], 1.03-1.06), dyspnea (OR, 2.56; 95% CI: 1.51-4.33), male sex (OR, 1.70; 95% CI: 1.10-2.64), immunocompromised status (OR, 2.22; 95% CI: 1.17-4.16) and CKD (OR, 1.76; 95% CI: 1.01-3.06) were significant predictors of severe Covid-19 infection. Hyperlipidemia was found to be negatively associated with severe disease (OR, 0.54; 95% CI: 0.33-0.90). A predictive equation based on these variables demonstrated fair ability to discriminate severe vs non-severe outcomes using only this historical information (AUC: 0.76).

Conclusions: Severe Covid-19 illness can be predicted using data that could be obtained from a remote screening. With validation, this model could possibly be used for remote triage to prioritize evaluation based on susceptibility to severe disease while avoiding unnecessary waiting room exposure.

Keywords: Covid-19; Remote triage; Severe; Symptoms.

Fig. 1

Schematic representation of the patient encounter inclusion process. *Covid-19 positive encounter window was defined as: -Positive PCR up to 3 weeks BEFORE index ED encounter -Positive PCR up to 2 weeks AFTER index ED encounter -Outside health system positive PCR up to 3 weeks before or 2 weeks after the index ED encounter #For patients with multiple ED encounters during the Covid-19 positive window, the encounter resulting in the highest level of care or most recent encounter (if all same level of care) during this window was used. Level of care was defined as ICU > Hospital Admission > ED encounter only.

Fig. 2

Receiver operator characteristic (ROC) curve demonstrating the discriminative ability of our model applied to our total cohort of patients.