Estimated prevalence of undiagnosed atrial fibrillation in the United States

PLoS One. 2018 Apr 12;13(4):e0195088. doi: 10.1371/journal.pone.0195088. eCollection 2018.


Introduction: As atrial fibrillation (AF) is often asymptomatic, it may remain undiagnosed until or even after development of complications, such as stroke. Consequently the observed prevalence of AF may underestimate total disease burden.

Methods: To estimate the prevalence of undiagnosed AF in the United States, we performed a retrospective cohort modeling study in working age (18-64) and elderly (≥65) people using commercial and Medicare administrative claims databases. We identified patients in years 2004-2010 with incident AF following an ischemic stroke. Using a back-calculation methodology, we estimated the prevalence of undiagnosed AF as the ratio of the number of post-stroke AF patients and the CHADS2-specific stroke probability for each patient, adjusting for age and gender composition based on United States census data.

Results: The estimated prevalence of AF (diagnosed and undiagnosed) was 3,873,900 (95%CI: 3,675,200-4,702,600) elderly and 1,457,100 (95%CI: 1,218,500-1,695,800) working age adults, representing 10.0% and 0.92% of the respective populations. Of these, 698,900 were undiagnosed: 535,400 (95%CI: 331,900-804,400) elderly and 163,500 (95%CI: 17,700-400,000) working age adults, representing 1.3% and 0.09% of the respective populations. Among all undiagnosed cases, 77% had a CHADS2 score ≥1, and 56% had CHADS2 score ≥2.

Conclusions: Using a back-calculation approach, we estimate that the total AF prevalence in 2009 was 5.3 million of which 0.7 million (13.1% of AF cases) were undiagnosed. Over half of the modeled population with undiagnosed AF was at moderate to high risk of stroke.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / therapeutic use
  • Atrial Fibrillation / epidemiology*
  • Atrial Fibrillation / therapy*
  • Data Collection*
  • Female
  • Humans
  • Male
  • Medicare
  • Middle Aged
  • Prevalence
  • Probability
  • Retrospective Studies
  • Risk Assessment
  • Risk Factors
  • Stroke / complications*
  • United States
  • Young Adult


  • Anticoagulants

Grant support

The research reported in this manuscript was funded by Bristol-Myers Squibb and Pfizer based on a proposal that co-author Dana P. Goldman and Mintu P. Turakhia presented to the sponsors. Jason Shafrin and Katalin Bognar are employees of; Dana P. Goldman serves as a consultant to Precision Health Economics, who were paid consultants to Pfizer in connection with the development of this manuscript. Jeffrey Trocio, Younos Abdulsattar, and Daniel Wiederkehr are employees and shareholders of Pfizer, Inc. Bristol-Myers Squibb provided funding but was not involved in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. Through Pfizer-affiliated coauthors, Pfizer was involved in the design of the study, the interpretation of data, and the preparation, review, and approval of the manuscript for publication.