Association between Weather-Related Factors and Cardiac Arrest of Presumed Cardiac Etiology: A Prospective Observational Study Based on Out-of-Hospital Care Data

<p><b>Objective</b>: The objective of this study was to determine the association between weather-related factors and out-of-hospital cardiac arrest (OHCA) of presumed cardiac etiology. <b>Methods</b>: This was a prospective observational study performed in a prehospital setting. Data from the Emergency Medical Service in Hamburg (Germany) and data from the local weather station were evaluated over a 5-year period. Weather data (temperature, humidity, air pressure, wind speed) were obtained every minute and matched with the associated rescue mission data. Lowess-Regression analysis was performed to assess the relationship between the above-mentioned weather-related factors and OHCA of presumed cardiac etiology. Additionally, varying measuring-ranges were defined for each weather-related factor in order to compare them with each other with regard to the probability of occurrence of OHCA. <b>Results</b>: During the observation period 1,558 OHCA with presumed cardiac etiology were registered (age: 67 ± 19 yrs; 62% male; hospital admission: 37%; survival to hospital discharge: 6.7%). Compared to moderate temperatures (5 – 25°C), probability of OHCA-occurrence increased significantly at temperatures above 25°C (p = 0.028) and below 5°C p = 0.011). Regarding air humidity, probability of OHCA-occurrence increased below a threshold-value of 75% compared to values above this cut-off (p = 0.006). Decreased probability was seen at moderate atmospheric pressure (1000 hPa – 1020 hPa), whereas increased probability was seen above 1020 hPa (p = 0.023) and below 1000 hPa (p = 0.035). Probability of OHCA-occurrence increased continuously with increasing wind speed (p < 0.001). <b>Conclusions</b>: There are associations between several weather-related factors such as temperature, humidity, air pressure, and wind speed, and occurrence of OHCA of presumed cardiac etiology. Particularly dangerous seem to be cold weather, dry air and strong wind.</p

Model-based probabilities of mortality by virus type and variant.

Wild-type to delta infection increased the risk for in-hospital mortality compared to influenza infection or omicron variant infection. Infection with the omicron variant was also associated with higher mortality, but the difference to influenza infection remains moderate.</p

Baseline data stratified by virus type and variant.

Baseline data stratified by virus type and variant.</p

Model summary: Prediction of mortality.

BackgroundWith the emergence of new subvariants, the disease severity of Severe Acute Respiratory Syndrome Coronavirus-2 has attenuated. This study aimed to compare the disease severity in patients hospitalized with omicron variant infection to those with influenza infection.MethodsWe compared data from the multicenter observational, prospective, epidemiological “CORONA Germany” (Clinical Outcome and Risk in hospitalized COVID-19 patients) study on patients infected with Severe Acute Respiratory Syndrome Coronavirus-2 to retrospective data on influenza infection cases from November 2016 to August 2022. Severe Acute Respiratory Syndrome Coronavirus-2 cases were classified as wild-type/delta variant before January 2022, or omicron variant from January 2022 onward. The primary outcome was in-hospital mortality, adjusted for age, gender, and comorbidities.ResultsThe study included 35,806 patients from 53 hospitals in Germany, including 4,916 patients (13.7%) with influenza infection, 16,654 patients (46.5%) with wild-type/delta variant infection, and 14,236 patients (39.8%) with omicron variant infection. In-hospital mortality was highest in patients with wild-type/delta variant infection (16.8%), followed by patients with omicron variant infection (8.4%) and patients with influenza infection (4.7%). In the adjusted analysis, higher age was the strongest predictor for in-hospital mortality (age 80 years vs. age 50 years: OR 4.25, 95% CI 3.10–5.83). Both, patients with wild-type/delta variant infection (OR 3.54, 95% CI 3.02–4.15) and patients with omicron variant infection (OR 1.56, 95% CI 1.32–1.84) had a higher risk for in-hospital mortality than patients with influenza infection.ConclusionAfter adjusting for age, gender and comorbidities, patients with wild-type/delta variant infection had the highest risk for in-hospital mortality compared to patients with influenza infection. Even for patients with omicron variant infection, the adjusted risk for in-hospital mortality was higher than for patients with influenza infection. The adjusted risk for in-hospital mortality showed a strong age dependency across all virus types and variants.Trial registration numberNCT04659187.</div

Primary and secondary outcomes stratified by virus type and variant.

Primary and secondary outcomes stratified by virus type and variant.</p

Model effects from the adjusted logistic regression model.

Model effects from the adjusted logistic regression model.</p

Forest plot of model effects.

When adjusted for age, gender, and comorbidities, age, liver cirrhosis/fibrosis and tumor disease had a strong impact on in-hospital mortality. Among virus groups, patients with wild-type to delta variant infection had a higher risk for in-hospital mortality compared to patients with influenza infection. Furthermore, patients with omicron variant infection had a higher risk for in-hospital mortality when compared to patients with influenza infection. COPD indicates chronic obstructive pulmonary disease.</p

Definition of virus variants.

BackgroundWith the emergence of new subvariants, the disease severity of Severe Acute Respiratory Syndrome Coronavirus-2 has attenuated. This study aimed to compare the disease severity in patients hospitalized with omicron variant infection to those with influenza infection.MethodsWe compared data from the multicenter observational, prospective, epidemiological “CORONA Germany” (Clinical Outcome and Risk in hospitalized COVID-19 patients) study on patients infected with Severe Acute Respiratory Syndrome Coronavirus-2 to retrospective data on influenza infection cases from November 2016 to August 2022. Severe Acute Respiratory Syndrome Coronavirus-2 cases were classified as wild-type/delta variant before January 2022, or omicron variant from January 2022 onward. The primary outcome was in-hospital mortality, adjusted for age, gender, and comorbidities.ResultsThe study included 35,806 patients from 53 hospitals in Germany, including 4,916 patients (13.7%) with influenza infection, 16,654 patients (46.5%) with wild-type/delta variant infection, and 14,236 patients (39.8%) with omicron variant infection. In-hospital mortality was highest in patients with wild-type/delta variant infection (16.8%), followed by patients with omicron variant infection (8.4%) and patients with influenza infection (4.7%). In the adjusted analysis, higher age was the strongest predictor for in-hospital mortality (age 80 years vs. age 50 years: OR 4.25, 95% CI 3.10–5.83). Both, patients with wild-type/delta variant infection (OR 3.54, 95% CI 3.02–4.15) and patients with omicron variant infection (OR 1.56, 95% CI 1.32–1.84) had a higher risk for in-hospital mortality than patients with influenza infection.ConclusionAfter adjusting for age, gender and comorbidities, patients with wild-type/delta variant infection had the highest risk for in-hospital mortality compared to patients with influenza infection. Even for patients with omicron variant infection, the adjusted risk for in-hospital mortality was higher than for patients with influenza infection. The adjusted risk for in-hospital mortality showed a strong age dependency across all virus types and variants.Trial registration numberNCT04659187.</div

Model summary: Prediction of ventilation and effect sizes.

Model summary: Prediction of ventilation and effect sizes.</p

Data dictionary.

The processed data, labels, variable type and values. (DOCX)</p