Initial clinical characteristics of gravid SARS-CoV-2 positive patients and the risk of progression to severe COVID-19 disease

Yao, Ruofan; Martin, Courtney B; Haase, Victoria S; Tse, Beverly C; Nishino, Ms Melissa; Gheorghe, Ciprian; Balli, Kevin

OBJECTIVES: This retrospective cohort study sought to evaluate the initial clinical characteristics of pregnant patients diagnosed with SARS-CoV-2 infection, and to develop a pregnancy specific early warning score to identify patients at risk of clinical deterioration and requiring advanced respiratory support (ARS). STUDY DESIGN: This was a single center retrospective cohort study of pregnant patients diagnosed with SARS-CoV-2 infection between April 2020 and December 2020. Fifty patients with SARS-CoV-2 infection between April and November were used to create the prediction model. Initial clinical characteristics identified at the time of diagnosis were compared between patients who required ARS and patients who were asymptomatic or had mild symptoms, using patients diagnosed between April and November 2020. Risk factors associated with ARS requirement were used to create the Obstetric Warning Score (OWS). The OWS score was then validated using 30 patients diagnosed with SARS-CoV-2 infection in December 2020. Receiver operator curve (ROC) was generated to evaluate the test characteristics of OWS compared to other scoring systems including the Early Warning Score (EWS), the National Early Warning Score 2 (NEWS2) and the Maternal Early Warning Criteria (MEWC). RESULTS: Women who required ARS were more likely to present with dyspnea (100% vs. 33.3%, p<0.001), have higher heart rate (113.4 bpm vs. 93 bpm, p<0.001), respiratory rate (23.5 bpm vs. 17.7 bpm, p<0.001), temperature (99.1 °F vs. 98.3 °F, p=0.004) and C-Reactive Protein (CRP) (7.4 mg/dL vs. 2.4 mg/dL, p<0.001). Furthermore, 88.2% of ARS patients showed chest x-ray findings consistent with pneumonia, compared to 20.0% of non-ARS patients (p<0.001). All ARS patients presented with at least one COVID-19 symptom, while 51.5% of non-ARS patients were symptomatic (p<0.001). The OWS model included 1 point each for HR > 100 bpm, temperature > 99.0 °F, CRP >2.0 mg/dL, respiratory rate between 20 and 24 bpm, complaints of dyspnea and positive chest x-ray. Respiratory rate >24 bpm was assigned 2 points. The AUC for OWS is 0.97 compared with 0.72 for EWS, 0.92 for NEWS2 and 0.85 for MEWC. An OWS score ≥3 was predictive of ARS requirement with a sensitivity of 100%, specificity 64%, and positive predictive value of 36%. CONCLUSIONS: The OWS presents a validated method for providers to identify pregnant patients who are at risk of respiratory failure and requiring advanced respiratory support (ARS).