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Objectives We report on the key clinical predictors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and present a clinical decision rule that can risk stratify patients for COVID-19. Design, participants and setting A prospective cohort of patients assessed for COVID-19 at a screening clinic in Melbourne, Australia. The primary outcome was a positive COVID-19 test from nasopharyngeal swab. A backwards stepwise logistic regression was used to derive a model of clinical variables predictive of a positive COVID-19 test. Internal validation of the final model was performed using bootstrapped samples and the model scoring derived from the coefficients, with modelling performed for increasing prevalence. Results Of 4226 patients with suspected COVID-19 who were assessed, 2976 patients underwent SARS-CoV-2 testing (n = 108 SARS-CoV-2 positive) and were used to determine factors associated with a positive COVID-19 test. The 7 features associated with a positive COVID-19 test on multivariable analysis were: COVID-19 patient exposure or international travel, Myalgia/malaise, Anosmia or ageusia, Temperature, Coryza/sore throat, Hypoxia–oxygen saturation < 97%, 65 years or older—summarized in the mnemonic COVID-MATCH65. Internal validation showed an AUC of 0.836. A cut-off of ≥ 1.5 points was associated with a 92.6% sensitivity and 99.5% negative predictive value (NPV) for COVID-19. Conclusions From the largest prospective outpatient cohort of suspected COVID-19 we define the clinical factors predictive of a positive SARS-CoV-2 test. The subsequent clinical decision rule, COVID-MATCH65, has a high sensitivity and NPV for SARS-CoV-2 and can be employed in the pandemic, adjusted for disease prevalence, to aid COVID-19 risk-assessment and vital testing resource allocation.

Relative hypoglycemia is a decrease in glucose greater than or equal to 30% below prehospital admission levels (estimated by hemoglobin A1C) but not to absolute hypoglycemia levels. It is a recognized pathophysiologic phenomenon in ambulant poorly controlled diabetic patients but remains unexamined during critical illness. We examined the frequency, characteristics, and outcome associations of relative hypoglycemia in diabetic patients with critical illness. Design: Retrospective cohort study. Setting: ICU of a tertiary hospital. Patients: One-thousand five-hundred ninety-two critically ill diabetic patients between January 2013 and December 2017. Interventions: None. Measurements and Main Results: The median age of patients was 67 years (interquartile range, 60-75 yr). The median Acute Physiology and Chronic Health Evaluation III score was 53 (interquartile range, 40-68). Thirty-four percent of patients with diabetes experienced relative hypoglycemia (exposure) during their ICU admission. Such patients had higher glycemic lability, hemoglobin A1C levels, and Acute Physiology and Chronic Health Evaluation III scores. The hazard ratio for 28-day mortality of diabetic patients, censored at hospital discharge, for patients with relative hypoglycemia was 1.9 (95% CI, 1.3-2.8) and was essentially unchanged after adjustment for episodes of absolute hypoglycemia. After an episode of relative hypoglycemia, the hazard ratio for subsequent absolute hypoglycemia in the ICU was 3.5 (95% CI, 2.3-5.3). Conclusions: In ICU patients with diabetes, relative hypoglycemia is common, increases with higher hemoglobin A1C levels, and is a modifiable risk factor for both mortality and subsequent absolute hypoglycemia. These findings provide the rationale for future interventional studies to explore new blood glucose management strategies and to substantiate the clinical relevance of relative hypoglycemia. (Crit Care Med 2020; 48:e233-e240)