Wednesday, September 28, 2022

Predictive direction and magnitude of all-cause mortality after hospitalization with influenza, RSV, or SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic, caused by the rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has put immense strain on health systems around the world. It is important to identify individuals at highest risk for quick decision making and devise treatment strategies. This is especially important when dealing with novel respiratory viruses. The identification of shared and divergent determinants of clinical severity in respiratory viruses is also important when dealing with new or re-emerging respiratory pathogens.

Study: Prediction of all-cause mortality in hospitalized patients with influenza, respiratory syncytial virus, or SARS-CoV-2.  Image credit: Gorodenkopf / Shutterstock
Study: Prediction of all-cause mortality in hospitalized patients with influenza, respiratory syncytial virus, or SARS-CoV-2. Image credit: Gorodenkopf / Shutterstock

In a new study published on medrxiv*Preprint Server, researchers conducted a retrospective cohort study to identify predictors of mortality after hospitalization with influenza, respiratory syncytial virus, or SARS-CoV-2. Population-based health administrative data from Ontario, Canada were used for this analysis.


Previous research has compared (shared and divergent) determinants of critical illness outcomes in patients with influenza and respiratory syncytial virus (RSV). However, not many papers have addressed the issue of comparing predictors of severity in influenza, RSV, and SARS-CoV-2.

Given that countries are gradually returning to pre-pandemic contact and exposure patterns, the risk of respiratory infections may increase. There is also a possibility that only a fraction of hospitalized patients with viral respiratory illness will receive a laboratory-confirmed diagnosis. Therefore, identifying shared predictors of disease may help reduce morbidity and mortality and design health care settings that should require more resources based on the prevalence of the identified predictors.

a new study

In the current study, scientists conducted an observational study using comprehensive health administrative data from Ontario, Canada. Their aim was to identify the direction and magnitude of shared and divergent predictors of 30-day all-cause mortality.

The researchers focused on patients hospitalized with influenza, RSV, or SARS-CoV-2. The sample included 45,749 influenza patients hospitalized between September 2011 and May 2019, 24,345 RSV patients hospitalized between September 2011 and April 2019, and 8,988 SARS-CoV patients hospitalized between March 2020 and December 2020 (pre-vaccine). 2 patients were included.

Associations between potential predictors and mortality were assessed using the multivariable modified Poisson regression technique. The direction, magnitude and confidence intervals of risk ratios were compared to identify shared and different predictors of mortality.

key findings

Common predictors of 30-day all-cause mortality after hospitalization included older age, male gender, residence in a long-term care home (LTCH), and chronic kidney disease. In all respiratory groups, older age and male sex were predictive of increased mortality, especially in patients with SARS-CoV-2. It emphasizes the need to prioritize age and gender in clinical practice and consider them for targeted COVID-19 prevention and therapeutic guidance.

In addition to age and gender, LTCH residence was also a common predictor of 30-day all-cause mortality. In this case, the associations were weaker in SARS-CoV-2 patients. These differences may be driven by selection bias. To further clarify, consider that during the first wave of the pandemic in Ontario, 24.3% of COVID-19-positive LTCH residents were hospitalized before death, compared to 79.3% of residents of a SARS-CoV-2-infected community. was admitted in. The number of hospitalizations of COVID-19 patients could have been lower due to limited resources.

Chronic kidney disease was found to increase the risk of 30-day all-cause mortality. The magnitudes were similar for influenza, RSV and SARS-CoV-2 patients. Other comorbidities were found to predict mortality in patients with influenza or RSV, but not SARS-CoV-2, probably because of the smaller sample size in the case of SARS-CoV-2, less severe SARS-CoV-2 patients. due to more hospitalizations. , and/or clinical differences between patients requiring hospitalization with SARS-CoV-2 versus seasonal influenza or RSV.

The researchers did not see an association between mortality and local social determinants of health for all three viruses. He said this result may have been driven by misclassification of neighborhood-level social determinants of health, ecological fallacy, etc.


The current study has some limitations, including the possible misclassification of influenza and RSV cases. Patients were not identified using their clinical test results, which could lead to such misclassification. However, the researchers noted that abortion should be rare because the case definitions were validated against a population of hospitalized patients. A second limitation was the lack of data on other predictors of disease severity, such as pregnancy and obesity. These limitations should be considered when using the results to prioritize services or develop clinical prediction tools.


In the current study, the authors identified common predictors of 30-day all-cause mortality after hospitalization with SARS-CoV-2, influenza, or RSV. This work is important because common predictors can help identify patients at greatest risk of developing serious disease and prioritize prevention and treatment during viral pandemics.

*Important Information

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be considered conclusive, should guide clinical practice/health-related behavior, or be regarded as established information.

Nation World News Desk
Nation World News Desk
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