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Joaquim Cardoso MSc
Chief Researcher & Editor of the Site
March 31, 2023
EXECUTIVE SUMMARY
11%–23% of an overall 5.6–6.6 million presumptive AF cases were considered undiagnosed, based on the assumptions of 1- (11%) and 2-year (23%) undiagnosed status, respectively.
- The study found that up to 1.5 million patients with presumptive AF were undiagnosed, despite being eligible for oral anticoagulant treatment.
Undiagnosed AF cases are challenging to identify, as about one-third of AF cases are asymptomatic.
The study underscores the importance of early detection of AF and supports future research and policy initiatives aimed at addressing this diagnostic gap.
- Data from 2015 suggest an overall undiagnosed atrial fibrillation prevalence estimate of 11%.
- Undiagnosed patients were more likely to be women, to be older and to have more comorbidities.
DEEP DIVE
1.5 million atrial fibrillation cases may be undiagnosed in US
Cardiology Today
Regina Schaffer, Fact checked byRichard Smith
March 27, 2023
An analysis of five U.S. medical claims databases suggests as many as 23% of 5.6 million to 6.6 million presumptive atrial fibrillation cases are undiagnosed, with many undiagnosed patients likely eligible for oral anticoagulant treatment.
“[A] barrier to determining AF prevalence is the presence of undiagnosed AF,” Mintu P. Turakhia, MD, MAS, associate professor of cardiovascular medicine at the Stanford School of Medicine, and colleagues wrote in in Clinical Cardiology.
“Undiagnosed AF cases are especially challenging, as it is estimated that about a third of the AF population is asymptomatic. As such, it is often hospitalization for acute symptoms such as ischemic stroke that brings them to light. There is mounting evidence of considerable proportions of undiagnosed AF cases in the United States and Europe.”
In a retrospective study, Turakhia and colleagues analyzed patient information from five U.S. medical claims data sets from 2012 to 2017.
Researchers estimated undiagnosed AF based on the observed incidence of ischemic stroke, systemic embolism and AF incidence after a stroke or systemic embolism.
The diagnosed AF cohort included patients with AF documented between the first quarter of 2014 and the third quarter of 2015.
The undiagnosed AF cohort were patients with assumed undiagnosed AF in the year before a stroke or systemic embolism and who were newly diagnosed with AF in the 3 months after stroke or systemic embolism.
Researchers calculated the incidence of stroke and systemic embolism among all patients with AF and the ratio of number of undiagnosed AF patients to stroke rate. Age‐ and sex‐adjusted estimates were stratified by a period of assumed undiagnosed AF before an AF diagnosis (1 or 2 years).
The estimated U.S. prevalence of AF (diagnosed and undiagnosed) in the third quarter of 2015 was 5,628,000 cases, of which 11% were undiagnosed.
The assumed 2‐year undiagnosed AF prevalence was 23% of the total prevalent patients with AF. Compared with diagnosed patients, those who remained undiagnosed tended to be women, to be older, to have more comorbidities and to have higher CHA2DS2‐VASc scores.
“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,” the researchers wrote.
“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.”
Originally published at https://www.healio.com
Mintu P. Turakhia, MD, MAS, associate professor of cardiovascular medicine at the Stanford School of Medicine
REFERENCE PUBLICATION
Contemporary prevalence estimates of undiagnosed and diagnosed atrial fibrillation in the United States
Clinical Cardiology (Wiley)
Mintu P. Turakhia MD, MAS, Jennifer D. Guo PhD, Allison Keshishian MPH, Rachel Delinger MPH, Xiaoxi Sun MA, Mauricio Ferri MD, Cristina Russ MD, Matthew Cato MPH, Huseyin Yuce PhD, Patrick Hlavacek MPH
First published: 01 March 2023
ABSTRACT
Background
- Atrial fibrillation (AF) prevalence estimates vary and have been based on cohorts with clinically established or diagnosed disease.
- Undiagnosed AF prevalence estimates are less certain as they are based on nongeneralizable convenience samples.
Hypothesis
- Because AF is often asymptomatic, it my remain undiagnosed until the development of complications such as stroke or heart failure.
- Consequently, the observed prevalence of diagnosed AF from the literature may underestimate total disease burden.
- We therefore sought to estimate the total prevalence of both diagnosed and undiagnosed AF.
Methods
- We performed a retrospective cohort study from 2012 to 2017 using data from five US medical claims data sets.
- Undiagnosed AF prevalence was estimated based on the observed incidence of ischemic stroke, systemic embolism (SE), and AF incidence after a stroke/SE.
- The diagnosed AF cohort included AF patients between Q1 2014 and Q3 2015.
- The undiagnosed AF cohort were patients with assumed undiagnosed AF in the year before a stroke/SE and who were newly diagnosed with AF in the 3-month poststroke/SE.
- Stroke/SE incidence was calculated among all AF patients and the ratio of number of undiagnosed AF patients to stroke rate was created.
- Age- and sex-adjusted estimates were stratified by period of assumed undiagnosed AF before poststroke/SE AF diagnosis (1 or 2 years).
Results
- The estimated US prevalence of AF (diagnosed and undiagnosed) in Q3 2015 was 5 628 000 cases, of which 591 000 cases (11%) were undiagnosed.
- The assumed 2-year undiagnosed AF prevalence was 23% (1 531 000) of the total prevalent patients with AF (6 568 000).
- Undiagnosed (vs. diagnosed) AF patients were older and had higher CHA2DS2-VASc scores.
- Of undiagnosed AF, 93% had CHA2DS2-VASc ≥2 and met OAC criteria.
Conclusions
- These contemporary estimates demonstrate the high prevalence of undiagnosed AF in the United States.
- Undiagnosed AF patients are composed of primarily elderly individuals who if diagnosed, would meet criteria for stroke prevention therapy.
