A recent Scientific Reports study investigated the incidence and prognosis of newly diagnosed atrial fibrillation (AF) in patients hospitalized due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causal agent of the coronavirus disease 2019 (COVID-19) pandemic.
Study: Incidence and prognostic significance of newly-diagnosed atrial fibrillation among older U.S. veterans hospitalized with COVID-19. Image Credit: Nakharin T/Shutterstock.com
Background
Recent studies have shown that 5–10% of hospitalized patients with sepsis develop AF. These patients may also require admission to intensive care units (ICU). AF development has been seen to increase in-hospital mortality.
A recent study indicated that newly diagnosed AF led to a worsening of COVID-19 prognosis.
A couple of US-based multicenter studies on patients hospitalized with COVID-19 observed a newly diagnosed AF that enhanced the mortality rate of these patients.
This observation was contradicted by another study based on participants enlisted in the American Heart Association COVID-19 Cardiovascular Registry that revealed newly diagnosed AF has no link with in-hospital mortality.
It is unclear whether the existing studies differentiated pre-existing AF from newly diagnosed AF while assessing the effect of AF on hospitalized COVID-19 patients.
This misclassification would significantly affect the study's finding on the association between newly diagnosed AF and adverse COVID-19 outcomes.
About the study
The current study used nationwide longitudinal data from the US Veterans Health Administration (VHA) to classify pre-existing and newly diagnosed AF accurately. This data comprises medical information on patients hospitalized due to SARS-CoV-2 infection.
The main objective of this study is to assess the incidence rates of newly diagnosed AF in patients hospitalized with COVID-19. The association between freshly diagnosed AF and in-hospital mortality was also evaluated.
Veterans above 65 years of age who contracted SARS-CoV-2 infection between June 1, 2020, and January 31, 2022, were identified from the VHA Corporate Data Warehouse.
This data was linked with Medicare parts A, B, and D to determine the participants' comorbidities.
Patients hospitalized for more than 24 hours and less than a week and were regular users of VHA were considered in this study. This strategy enabled a better diagnostic specificity to differentiate between newly diagnosed AF and pre-existing AF.
Study finding
A total of 23,299 patients were included in the study cohort. The mean age of the patients was 76 years, and the majority of the study cohort was male. Although most participants were White, a minor proportion of American Indian, Native Hawaiian, Asian, Black, and Hispanic or Latino were present.
Around 7.5% of patients were newly diagnosed with AF. Around 29% of the study cohort possessed pre-existing AF.
Interestingly, compared to patients with pre-existing AF, the newly diagnosed AF patients were relatively younger and healthier, and most of them were Black individuals. These individuals were less likely to have both cardiovascular and non-cardiovascular comorbidities.
The majority of patients with pre-existing AF were being treated with beta-blockers, oral anticoagulants, and AF-specific antiarrhythmics.
In this study, the newly diagnosed AF was estimated to be 5.3%, and pre-existing AF was 29.2%.
The new AF diagnosis was linked to 16.5% of in-hospital and 22.7% of 30-day mortality. The current study indicated that compared to pre-existing AF, newly diagnosed AF increased the risk of mortality by 10%.
Strengths and limitations
The present study has many strengths, including the analysis of regular users of VHA and linking them to Medicare data. This strategy maximized the diagnostic specificity of new AF diagnosis and pre-existing AF.
The potential misclassification of pre-existing AF as newly diagnosed AF could be the reason why the American Heart Association COVID-19 Cardiovascular Registry failed to find a correlation between freshly diagnosed AF and in-hospital mortality.
This study also has some limitations, including bias in AF diagnosis. There is a possibility of an elevated number of newly diagnosed AF due to the increased duration of cardiac rhythm monitoring.
The survival analysis was not performed by adjusting for time-varying covariates, as the precise timing of AF onset could not be determined.
Even though previous studies indicated that echocardiographic features, such as left ventricular wall thickness, left atrial size, and left ventricular ejection fraction, impact AF manifestations and clinical outcomes, these features were not considered due to lack of data access.
The study cohort was restricted to the US population, with the majority being White individuals, which limited the generalizability of the findings.
Conclusions
In sum, the current study indicated that compared to pre-existing AF, newly diagnosed AF in patients hospitalized due to COVID-19 increases the risk of mortality.
More research must be conducted in the future to determine whether newly diagnosed AF is a marker or contributor to poor disease outcomes. New strategies must be developed to prevent the onset of fresh AF during SARS-CoV-2 infection.
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