Proposed Clinical Indicators for Efficient Screening and Testing for COVID-19 Infection from Classification and Regression Trees (CART) Analysis

Abstract

Background: The introduction and rapid transmission of SARS CoV2 in the United States resulted in implementation of methods to assess, mitigate and contain the resulting COVID-19 disease based on limited knowledge. Screening for testing has been based on symptoms typically observed in inpatients, yet outpatient symptom complexes may differ. Methods: Classification and regression trees (CART) recursive partitioning created a decision tree classifying enrollees into laboratory-confirmed cases and non-cases. Demographic and symptom data from patients ages 18-87 years who were enrolled from March 29-April 26, 2020 were included. Presence or absence of SARSCoV2 was the target variable. Results: Of 736 tested, 55 were positive for SARS-CoV2. Cases significantly more often reported chills, loss of taste/smell, diarrhea, fever, nausea/vomiting and contact with a COVID-19 case, but less frequently reported shortness of breath and sore throat. A 7-terminal node tree with a sensitivity of 96% and specificity of 53%, and an AUC of 78% was developed. The positive predictive value for this tree was 14% while the negative predictive value was 99%. Almost half (44%) of the participants could be ruled out as likely non-cases without testing. Discussion: Among those referred for testing, negative responses to three questions could classify about half of tested persons with low risk for SARS-CoV2 and would save limited testing resources. These questions are: was the patient in contact with a COVID-19 case? Has the patient experienced 1) a loss of taste or smell; or 2) nausea or vomiting? The outpatient symptoms of COVID-19 appear to be broader than the well-known inpatient syndrome.

Clinical symptoms among ambulatory patients tested for SARS-CoV-2

“…3 Missing for 19 (<1%) participants. 4 Only asked of participants aged ≥18 years. Denominators were 861 (3 adults did not answer) for persons with COVID-19 and 3470 (16 adults did not answer) for persons without COVID-19.…”

“…In addition to establishing clinical criteria for mild illness to evaluate interventions to prevent COVID-19, systematic testing for SARS-CoV-2 and influenza will be needed when both viruses circulate for assessing effectiveness of 2020–2021 seasonal influenza vaccines [4, 9]. Symptom criteria that can be rapidly assessed before enrollment in research studies of influenza and COVID-19 would help ensure systematic testing for both viruses.…”

“…Eligible individuals reported acute illness with fever/feverishness, cough, or shortness of breath/difficulty breathing and had a respiratory specimen collected for SARS-CoV-2 testing within 10 days of illness onset. At four sites, research staff contacted and screened patients for eligibility by telephone; at one site (Pennsylvania), a sample of potentially eligible patients was screened for eligibility by phone or online survey [4]. Standardized questionnaires collected demographic information, general health status, health-related behaviors such as cigarette smoking or vaping, healthcare-related employment, and contact with a person with confirmed COVID-19.…”

Facility-Level Case Report of Nursing Care Processes for Patients With Suspected 2019 Novel Coronavirus Disease in Shanghai, China

“…Some patients with COVID-19 lose their senses of smell (anosmia) and taste (ageusia). 30 , 31 , 32 Most patients with anosmia or ageusia recovered within 3 weeks. 30 However, many viral infections and upper respiratory tract infections can cause anosmia and ageusia through damage to the olfactory epithelium.…”

Pragmatic Recommendations for Identification and Triage of Patients with COVID-19 Disease in Low- and Middle-Income Countries

“…Four international guidelines described methods of screening patients for COVID-19 without the use of rapid antigen or reverse transcriptase (RT)-PCR testing. Just three of these tools—one 8 from the United States and two from China 9 , 10 (an upper-middle–income country)—included associated validation data.…”