Atrial fibrillation without comorbidities: Prevalence, incidence and prognosis (from the Framingham Heart Study).
The epidemiology of atrial fibrillation (AF) without comorbidities, known as 'lone AF', is uncertain. Although it has been considered a benign condition, we hypothesized that it confers a worse prognosis compared with a matched sample without AF.



We described the proportion of AF without comorbidities (clinical, subclinical cardiovascular disease and triggers) among the entire AF sample in Framingham Heart Study (FHS). We compared AF without comorbidities with typical AF, and age-, sex- and cohort-matched individuals without AF, using Cox proportional hazards analysis in relation to combined cardiovascular events (stroke, heart failure, myocardial infarction), and mortality.



Of 10,311 FHS participants, 1,961 were diagnosed with incident AF, among which 173 individuals had AF without comorbidities (47% women, mean age 71±12 years). AF without comorbidities had a prevalence of 1.7% of the entire cohort, and an annual incidence of 0.5 per 1000 person-years. During a median follow-up of 9.7 years after initial AF, 137 individuals with AF without comorbidities (79.2%) died and 141 individuals developed cardiovascular events (81.5%). AF without comorbidities had significantly lower mortality (HR 0.67, 95%CI 0.55-0.81, P < .001) and total cardiovascular events (HR 0.66, 95% CI 0.55-0.80, P < .001) compared with typical AF. However, mortality (HR1.43, 95% CI 1.18-1.75, P < .001) and risk of total cardiovascular events (HR 1.73, 95% CI 1.39-2.16, P < .001) were higher than age-, sex-, and cohort-matched individuals without AF.



The risk of cardiovascular outcomes and mortality among individuals with AF without comorbidities is lower than typical AF, but is significantly elevated compared with matched individuals without AF.
Department of Medicine, Section of General Internal Medicine, Massachusetts General Hospital, Boston, MA.
Eun-Jeong
EJ
Kim
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA.
Xiaoyan
X
Yin
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA.
João D
JD
Fontes
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA; Section of Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, MA.
Jared W
JW
Magnani
Cardiovascular Research Center and Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA; Program in Medical and Population Genetics, The Broad Institute of Harvard and MIT, Cambridge, MA.
Steve A
SA
Lubitz
Departments of Medicine and Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA.
David D
DD
McManus
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA; Departments of Neurology, Boston University School of Medicine, Boston, MA.
Sudha
S
Seshadri
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA; Section of Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, MA; Section of Preventive Medicine, Department of Medicine, Boston University School of Medicine, MA.
Ramachandran S
RS
Vasan
Cardiovascular Research Center and Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA; Program in Medical and Population Genetics, The Broad Institute of Harvard and MIT, Cambridge, MA.
Patrick T
PT
Ellinor
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA; Department of Mathematics and Statistics, Boston University, MA; Department of Biostatistics, Boston University School of Public Health, MA.
Martin G
MG
Larson
National Heart Lung and Blood Institute's and Boston University's Framingham Heart Study, Framingham, MA; Section of Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, MA; Section of Preventive Medicine, Department of Medicine, Boston University School of Medicine, MA; Department of Epidemiology, Boston University School of Public Health, Boston, MA.
Emelia J
EJ
Benjamin
Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: m.rienstra@umcg.nl.
Michiel
M
Rienstra
D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D009026:Mortality; D009203:Myocardial Infarction / Q000453:epidemiology*; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D020521:Stroke / Q000453:epidemiology*