Welcome to Study of the Week from Patient Worthy. In this segment, we select a study we posted about from the previous week that we think is of particular interest or importance and go more in-depth. In this story we will talk about the details of the study and explain why it’s important, who will be impacted, and more.
If you read our short form research stories and find yourself wanting to learn more, you’ve come to the right place.
This week’s study is…
Contemporary prevalence estimates of undiagnosed and diagnosed atrial fibrillation in the United States
We previously published about this research in a story titled “Atrial Fibrillation May Be Significantly Underdiagnosed” which can be found here. The study was originally published in the research journal Clinical Cardiology. You can read the full text of the study here.
This research team was affiliated with the Stanford School of Medicine.
What Happened?
Atrial fibrillation is an abnormal heart rhythm that can be difficult to detect because it doesn’t cause symptoms in up to a third of cases. The prevalence estimates of the condition vary substantially and are typically based on cohorts of confirmed diagnoses. Estimates of rates of undiagnosed atrial fibrillation are even more speculative as they are usually based around nongeneralizable convenience samples. The goal of this study was to provide a more accurate estimate of atrial fibrillation prevalence, both diagnosed and undiagnosed.
Utilizing data from five US medical claims databases, this retrospective cohort study drew on data from 2012 to 2017. The prevalence of undiagnosed atrial fibrillation was based on the incidence of events such as systemic embolism and ischemic stroke, as well as cases of the condition that were identified after such events. The diagnosed cohort included patients identified from the first quarter 2014 through third quarter 2015. The undiagnosed cohort included cases of assumed undiagnosed AF in the year before embolism or stroke and who were diagnosed in the three months after.
The research team calculated the rates of stroke and embolism among all patients as well as the ratio of undiagnosed patients to rates of stroke. According to the calculations of this study, atrial fibrillation prevalence was 5,628,000 cases. 11% percent of those cases were undiagnosed. Of the total patients with the condition, the two-year undiagnosed prevalence was 23%. Undiagnosed patients tended to be older, have more comorbidities, higher CHA2DS2‐VASc scores, and were more likely to be women.
About Atrial Fibrillation
Atrial fibrillation, sometimes called a-fib, is an abnormal heart rhythm, typically irregular, rapid beats of the atrial chambers. It can appear alongside other types of cardiovascular illness as well as on its own. Risk factors include a family history of the condition, a sedentary, inactive lifestyle, heavy alcohol use, tobacco smoking, certain medications, and high blood pressure. Symptoms are not always noticeable but can include rapid heartbeat, palpitations, ischemic stroke, and transient ischemic attack (mini stroke). Other symptoms that often appear are the result of an underlying disease that is causing atrial fibrillation; these symptoms can include weight loss, chest pain, diarrhea, and hyperthyroidism. Treatment for atrial fibrillation may include anticoagulants, beta blockers or other medications to bring down heartrate, surgery (such as catheter ablation), cardioversion, and lifestyle changes. To learn more about atrial fibrillation, click here.
Why Does it Matter?
The findings from the study suggest an increasing overall prevalence and in undiagnosed cases of atrial fibrillation:
“The data we generated from back‐calculation suggest considerable proportions of undiagnosed patients, in the context of growing overall prevalence, with diagnosed cases increasing from 3.7 to 5 million within 2 years and as many as 1.5 million presumptive undiagnosed cases at the end of that period. Together with the known burden of AF, this expanding unmet need underscores the critical importance of early detection. Our data can support both disease surveillance and future research and policy initiatives aimed at addressing this diagnostic gap.” – Mintu P. Turakhia, MD, MAS, Associate Professor, Cardiovascular Medicine, Stanford School of Medicine, and colleagues
Early detection and treatment are critical for improving outcomes in atrial fibrillation. Many undiagnosed patients would be eligible for treatment with anticoagulants.
