Clinical Prediction Tool to Assess the Likelihood of a Positive SARS-Cov-2 (COVID-19) Polymerase Chain Reaction Test in Patients with Flu-like Symptoms

Abstract

Introduction The clinical presentation of coronavirus disease 2019 (COVID-19) overlaps with many other common cold and influenza viruses. Identifying patients with a higher probability of infection becomes crucial in settings with limited access to testing. We developed a prediction instrument to assess the likelihood of a positive polymerase chain reaction (PCR) test, based solely on clinical variables that can be determined within the time frame of an emergency department (ED) patient encounter. Methods We derived and prospectively validated a model to predict SARS-CoV-2 PCR positivity in patients visiting the ED with symptoms consistent with the disease. Results Our model was based on 617 ED visits. In the derivation cohort, the median age was 36 years, 43% were men, and 9% had a positive result. The median time to testing from the onset of initial symptoms was four days (interquartile range [IQR]: 2–5 days, range 0–23 days), and 91% of all patients were discharged home. The final model based on a multivariable logistic regression included a history of close contact (adjusted odds ratio [AOR] 2.47, 95% confidence interval [CI], 1.29–4.7); fever (AOR 3.63, 95% CI, 1.931–6.85); anosmia or dysgeusia (AOR 9.7, 95% CI, 2.72–34.5); headache (AOR 1.95, 95% CI, 1.06–3.58), myalgia (AOR 2.6, 95% CI, 1.39–4.89); and dry cough (AOR 1.93, 95% CI, 1.02–3.64). The area under the curve (AUC) from the derivation cohort was 0.79 (95% CI, 0.73–0.85) and AUC 0.7 (95% CI, 0.61–0.75) in the validation cohort (N = 379). Conclusion We developed and validated a clinical tool to predict SARS-CoV-2 PCR positivity in patients presenting to the ED to assist with patient disposition in environments where COVID-19 tests or timely results are not readily available.

The predictive role of symptoms in COVID-19 diagnostic models: A longitudinal insight

“…Unlike many other studies [ 6 – 8 , 10 , 16 ], this research examined the number of days that specific symptoms are reported within an infection episode. We found that PCR+ participants reported a significantly longer duration of specific symptoms per episode, compared with those that were PCR−; cough had the longest duration followed by tiredness whilst runny nose had the longest duration among PCR− participants.…”

“…In the UK, PCR testing was initially prioritized for those presenting with a new (or worsening) cough, fever, or breathlessness [5]. However other symptoms such as altered or loss of smell (anosmia) or taste (ageusia), and gastrointestinal symptoms (such as loss of appetite and diarrhoea) have also been associated with COVID-19 [6][7][8]. In a Cochrane Review (2021), mainly based on more severely affected populations (e.g.…”

Sensitivity and specificity analyses of COVID-19 screening protocol for emergency medical services: A STARD-compliant population-based retrospective study

“…Among these, they reported that fever (odds ratio: 3.66, 95% CI: 2.97–4.50) and dry cough (odds ratio: 1.71, 95% CI: 1.39–2.12) were strongly associated with a COVID-19 diagnosis, which is consistent with the results of another previous report. [ 11 ] In contrast, others have reported that EMS encounters about 30% of those who were later confirmed to have COVID-19 but have no symptoms of fever, cough, or shortness of breath. [ 12 ] These upper respiratory symptoms are nonspecific and may not be sufficient for EMS to identify patients with COVID-19.…”

“…Epidemiological information, such as whether a patient visited areas where the number of COVID-19 cases is increasing and whether a patient was in contact with individuals who were confirmed/suspected to have COVID-19, can be helpful. Lara et al [ 11 ] reported that the odds ratio of such epidemiological information for COVID-19 was 2.47 (95% CI: 1.29–4.70), comparable to that of fever (odds ratio: 3.63, 95% CI: 1.93–6.85). However, this information may not be available, especially when the prevalence rates increase.…”

“…Our study results showed that the addition of clinical signs such as body temperature ≥37.5 °C, respiratory rate ≥20 breaths/minute, and SpO 2 < 90% can improve the sensitivity of the screening protocol. Although these signs are also nonspecific, [ 11 , 13 , 14 ] positive COVID-19 cases are likely to present with tachycardia, tachypnea, and/or low SpO 2 . [ 9 ] By adding 2 or more of these additional variables, the sensitivity of the screening protocol increased, while the specificity and PPV decreased.…”