Utility of conventional clinical risk scores in a low-risk COVID-19 cohort

Does the COVID-19 XBB Omicron subvariant signal the beginning of the end of the pandemic?

ABSTRACT

All pandemic viruses have eventually adapted to human hosts so that they become more transmissible and less virulent. The XBB Omicron subvariant is rapidly becoming the dominant strain of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Singapore from October 2022 and is one of several variants circulating globally with the potential to dominate autumn/winter waves in different countries. The XBB Omicron subvariant has demonstrated increased transmissibility through an apparent propensity for immune evasion. This is to be expected in the natural evolution of a virus in a population highly vaccinated with a vaccine targeting the spike protein of the original Wuhan strain of the virus. This review explores the important implications of the rising prevalence of the SARS-CoV-2 Omicron subvariant for public health in Singapore and beyond.

Adding Hyponatremia to the "Rule-of-6" Prediction Tool Improves Performance in Identifying Hospitalised Patients with COVID-19 at Risk of Adverse Clinical Outcomes

The 'rule-of-6' prediction tool was shown to be able to identify COVID-19 patients at risk of adverse outcomes. During the pandemic, we frequently observed hyponatremia at presentation. We sought to evaluate if adding hyponatremia at presentation could improve the 'rule-of-6' prediction tool. We retrospectively analysed 1781 consecutive patients admitted to a single tertiary academic institution in Singapore with COVID-19 infection from February 2020 to October 2021. A total of 161 (9.0%) patients had hyponatremia. These patients were significantly older, with more co-morbidities and more likely to be admitted during the Delta wave (2021). They were more likely to have radiographic evidence of pneumonia (46.0% versus 13.0%, p < 0.001) and more adverse outcomes (25.5% vs. 4.1%, p < 0.001). Hyponatremia remained independently associated with adverse outcomes after adjusting for age, lack of medical co-morbidities, vaccination status, year of admission, CRP, LDH, and ferritin. The optimised cut-off for serum sodium in predicting adverse outcomes was approximately <135 mmol/L as determined by the Youden index. Although derived in early 2020, the 'rule-of-6' prediction tool continued to perform well in our later cohort (AUC: 0.72, 95%CI: 0.66-0.78). Adding hyponatremia to the 'rule-of-6' improved its performance (AUC: 0.76, 95%CI: 0.71-0.82). Patients with hyponatremia at presentation for COVID-19 had poorer outcomes even as new variants emerged.

Trends in electrocardiographic and cardiovascular manifestations of patients hospitalised with COVID-19

INTRODUCTION

Early in the coronavirus disease 2019 (COVID-19) pandemic, a low incidence of cardiovascular complications was reported in Singapore. Little was known about the trend of cardiovascular complications as the pandemic progressed. In this study, we examined the evolving trends in electrocardiographic and cardiovascular manifestations in patients hospitalised with COVID-19.

METHODS

We examined the first 1781 consecutive hospitalised patients with polymerase chain reaction-confirmed COVID-19. We divided the population based on whether they had abnormal heart rate (HR) or electrocardiography (ECG) or normal HR and ECG, comparing the baseline characteristics and outcomes. Cardiovascular complications were defined as acute myocardial infarction, stroke, pulmonary embolism, myocarditis and mortality.

RESULTS

The 253 (14.2%) patients who had abnormal HR/ECG at presentation were more likely to be symptomatic. Sinus tachycardia was commonly observed. Troponin I levels (97.0 ± 482.9 vs. 19.7 ± 68.4 ng/L, P = 0.047) and C-reactive protein levels (20.1 ± 50.7 vs. 13.9 ± 24.1 μmol/L, P = 0.003) were significantly higher among those with abnormal HR/ECGs, with a higher prevalence of myocarditis (2.0% vs. 0.5%, P = 0.019), pulmonary embolism (2.0% vs. 0.3%, P = 0.008) and acute myocardial infarction (1.2% vs. 0.1%, P = 0.023). After adjusting for age and comorbidities, abnormal HR/ECG (adjusted odds ratio 4.41, 95% confidence interval 2.21-8.77; P < 0.001) remained independently associated with adverse cardiovascular complications. Over time, there was a trend towards a higher proportion of hospitalised patients with cardiovascular complications.

CONCLUSION

Cardiovascular complications appear to be increasing in proportion over time among hospitalised patients with COVID-19. A baseline ECG and HR measurement may be helpful for predicting these complications.

Evaluation of a virtual ward model of care and readmission characteristics during the COVID-19 pandemic within an Australian tertiary hospital

BACKGROUND

Virtual ward (VW) models of care established during the coronavirus disease 2019 (COVID-19) pandemic provided safe and equitable provision of ambulatory care for low-risk patients; however, little is known about patients who require escalation of care to hospitals from VWs.

AIM

To assess our VW model of care and describe the characteristics of patients admitted to the hospital from the VW.

METHODS

Observational study of all patients admitted to a tertiary hospital COVID-19 VW between 1 December 2021 and 30 June 2022. Utilisation and epidemiological characteristics were assessed for all patients while additional demographics, assessments, treatments and outcomes were assessed for patients admitted to the hospital from the VW.

RESULTS

Of 9494 patient admissions, 269 (2.83%) patients identified as Aboriginal and Torres Strait Islander and 1774 (18.69%) were unvaccinated. The median length of stay was 5.10 days and the mean Index of Relative Socio-economic Advantage and Disadvantage decile was 5.73. One hundred sixty (1.69%) patients were admitted to the hospital from the VW, of which 25 were adults admitted to medical wards. Of this cohort, prominent comorbidities were obesity, hypertension, asthma and frailty, while the main symptoms on admission to the VW were cough, fatigue, nausea and sore throat. High Pandemic Respiratory Infection Emergency System Triage (PRIEST), Veterans Health Administration COVID-19 (VACO), COVID Home Safely Now (CHOSEN) and 4C mortality scores existed for those readmitted.

CONCLUSIONS

This VW model of care was both safe and effective when applied to a broad socioeconomic population during the COVID-19 pandemic. While readmission to the hospital was low, this study identified key characteristics of such presentations, which may assist future triaging, escalation and resource allocation within VWs during the COVID-19 pandemic and beyond.

Predictors of disease severity in SARS-CoV-2 omicron variant XBB sublineages and variants of interest

The Omicron variant has been reported to present with milder disease compared with Delta, although this may be due to immunity from vaccination and prior exposure. Predictors of severity with recent strains have not been well characterized. We retrospectively examined consecutive cases of moderate-to-severe COVID-19 (defined as requiring supplemental oxygenation, intensive care or mortality) admitted to seven tertiary hospitals across Singapore in April 2023. Whole genome sequencing was performed on each isolate to determine the sublineage, while baseline clinical, laboratory data and outcomes were tabulated. We reviewed 182 patients with moderate-to-severe illness and 466 controls hospitalized at the same time. Advanced age and presence of chronic kidney disease predicted adverse outcome. Previously reported markers such as radiographic evidence of pneumonia, elevated C-reactive protein and serum creatinine levels at presentation also correlated with adverse outcomes. There were no observable differences in outcomes with any specific Omicron XBB sublineage. We did not find any specific Omicron XBB sublineage that was associated with worse outcomes. Larger multinational studies would be important to track the clinical evolution of the virus in its current endemic state.

Inflammatory phenotypes may be more important than age and comorbidities in predicting clinical outcomes in hospitalised patients with COVID-19

Objectives

In critically ill patients with COVID-19, distinct hyperinflammatory and hypoinflammatory phenotypes have been described, with different outcomes and responses to therapy. We investigated if similar phenotypes exist in non-severe illness.

Methods

Consecutive patients with polymerase chain reaction (PCR) confirmed SARS-CoV-2 were examined. Baseline demographics and laboratory investigations were tabulated, including serum C-reactive protein. Patients were divided into those who were hyperinflammatory (defined as C-reactive protein >17 mg/l) or hypoinflammatory. Adverse outcomes, defined as requiring oxygenation, intensive care, or death, were recorded during the hospital stay. Clinical characteristics and outcomes were compared.

Results

Of the 1781 patients examined, 276 (15.5%) had a hyperinflammatory phenotype. They were older (51.8 ± 17.2 vs 40.3 ± 13.8 years, P <0.001), had a lower PCR cycle threshold (PCR cycle threshold value 19.3 ± 6.3 vs 22.7 ± 15.4, P = 0.025) at presentation, and more medical comorbidities. The hyperinflammatory phenotype was independently associated with adverse clinical outcomes, even after adjusting for age, medical history and viral load on multivariable analyses (adjusted odds ratio 5.78, 95% confidence interval 2.86-11.63).

Conclusion

Even in non-severe COVID-19, there are distinct hyper- and hypoinflammatory phenotypes, with the hyperinflammatory phenotype strongly associated with adverse clinical outcomes, that could be distinguished with a simple biomarker.

Performance of CURB-65 and ISARIC 4C mortality scores for hospitalized patients with confirmed COVID-19 infection in Saudi Arabia

Background

The COVID-19 pandemic continues with new waves that could persist with the arrival of new SARS-CoV-2 variants. Therefore, the availability of validated and effective triage tools is the cornerstone for proper clinical management. Thus, this study aimed to assess the validity of the ISARIC-4C score as a triage tool for hospitalized COVID-19 patients in Saudi Arabia and to compare its performance with the CURB-65 score.

Material and methods

This retrospective observational cohort study was conducted between March 2020 and May 2021 at KFHU, Saudi Arabia, using 542 confirmed COVID-19 patient data on the variables relevant to the application of the ISARIC-4C mortality score and the CURB-65 score. Chi-square and t-tests were employed to study the significance of the CURB-65 score and the ISARIC-4C score variables considering the ICU requirements and the mortality of COVID-19 hospitalized patients. In addition, logistic regression was used to predict the variables related to COVID-19 mortality. In addition, the diagnostic accuracy of both scores was validated by calculating sensitivities, specificities, positive predictive value, negative predictive value, and Youden's J indices (YJI).

Results

ROC analysis showed an AUC value of 0.834 [95% CI; 0.800-0.865]) for the CURB-65 score and 0.809 [95% CI; 0.773-0.841]) for the ISARIC-4C score. The sensitivity for CURB-65 and ISARIC-4C is 75% and 85.71%, respectively, while the specificity was 82.31% and 62.66%, respectively. The difference between AUCs was 0.025 (95% [CI; -0.0203-0.0704], p = 0.2795).

Conclusion

Study results support external validation of the ISARIC-4C score in predicting the mortality risk of hospitalized COVID-19 patients in Saudi Arabia. In addition, the CURB-65 and ISARIC-4C scores showed comparable performance with good consistent discrimination and are suitable for clinical utility as triage tools for hospitalized COVID-19 patients.

Continued demographic shifts in hospitalised patients with COVID-19 from migrant workers to a vulnerable and more elderly local population at risk of severe disease

OBJECTIVES

In the early months of the COVID-19 pandemic in Singapore, the vast majority of infected persons were migrant workers living in dormitories who had few medical comorbidities. In 2021, with the Delta and Omicron waves, this shifted to the more vulnerable, elderly population within the local community. We examined evolving trends among the hospitalised cases of COVID-19.

METHODS

All patients with polymerase chain reaction-positive SARS-CoV-2 admitted from February 2020 to October 2021 were included and subsequently stratified by their year of admission (2020 or 2021). We compared the baseline clinical characteristics, clinical course, and outcomes.

RESULTS

A majority of cases were seen in 2020 (n = 1359), compared with 2021 (n = 422), due to the large outbreaks in migrant worker dormitories. Nevertheless, the greater proportion of locally transmitted cases outside of dormitories in 2021 (78.7% vs 12.3%) meant a significantly older population with more medical comorbidities had COVID-19. This led to an observably higher proportion of patients with severe disease presenting with raised inflammatory markers, need for therapeutics, supplemental oxygenation, and higher mortality.

CONCLUSION

Changing demographics and the characteristics of the exposed populations are associated with distinct differences in clinical presentation and outcomes. Older age remained consistently associated with adverse outcomes.

Validation of ISARIC 4C Mortality and Deterioration Scores in a Mixed Vaccination Status Cohort of Hospitalized Coronavirus Disease 2019 (COVID-19) Patients in Singapore

In this cross-sectional study, we studied performance of the International Severe Acute Respiratory and Emerging Infections Consortium mortality and deterioration scores in a cohort of 410 hospitalized patients (51.2% fully vaccinated). area under the receiver operating characteristic curves were 0.778 and 0.764, respectively, comparable to originally published validation cohorts. Subgroup analysis showed equally good performance in vaccinated and partially or unvaccinated patients.