Rising trend in atrial fibrillation risk over 20 years heightens concern for related heart and stroke complications

By Dr. Sushama R. Chaphalkar, PhD.Reviewed by Susha Cheriyedath, M.Sc.Apr 21 2024

In a recent Danish population-based cohort study published in the British Medical Journal, researchers analyzed the changes in lifetime risks of atrial fibrillation (AF) and complications. They compared the data between two periods, 2000-2010 and 2011-2022. They found that the lifetime risk of AF increased over the study period, and individuals with AF showed significant risks of heart failure (HF) and stroke over their lifetime.

Study: Temporal trends in lifetime risks of atrial fibrillation and its complications between 2000 and 2022: Danish, nationwide, population based cohort study. Image Credit: Magic mine / Shutterstock

Background

AF poses a growing health concern globally, with a substantial projected increase in affected populations. While improvements in mortality rates have been observed, AF remains linked to increased risks of stroke, HF, and myocardial infarction (MI). Understanding and effectively assessing AF risk, including its long-term complications, are crucial for prevention efforts. Residual lifetime risk, a measure capturing cumulative disease risk over the remaining lifespan, offers valuable insights for public health initiatives and patient education. Despite previous studies on AF lifetime risk, data on temporal trends and comprehensive complication risks are lacking. Monitoring changes in AF burden is vital for evaluating management strategies and prevention efforts, especially amid evolving stroke prevention therapies. In the present investigation involving the Danish population, researchers aimed to assess the lifetime risk of AF and its associated complications and to analyze their temporal trends spanning from 2000 to 2022.

About the study

Data were gathered from national registries, including the Danish National Patient Registry for hospital stays and outpatient contacts, the Civil Registration System for demographics and vital status, and the Danish National Prescription Registry for medication information. The study included 3,574,903 Danish individuals without AF at or after the age of 45 between 2000 and 2022. About 51.7% of the participants were women. Those aged 95 years or older were excluded. Follow-up ended at incident AF, death, age 95 years, emigration, or period end. Primary analysis used 45 years as the index age, with secondary analyses for ages 55, 65, and 75 or older. Incident AF was identified from hospital diagnoses.

A total of 362,721 individuals were followed up upon newly diagnosed AF (46.4% females). Complications, including HF, stroke, MI, or systemic embolism, were recorded post-diagnosis. Exclusions comprised pre-existing complications and events within seven days of diagnosis. The diagnosis followed strict International Classification of Diseases 10 (ICD-10) criteria with high predictive values. Analyses were conducted for index ages 45, 55, 65, and 75 years.

Study populations were characterized by assessing medical history along with family income and educational attainment. The statistical methods included the use of the Aalen-Johansen estimator for cumulative incidence, pseudo-value regression, propensity score adjustment using logistic regression, stabilized inverse propensity weighting, and subgroup analyses with interaction testing.

Results and discussion

Age distributions were found to remain consistent across the periods, while hypertension, dyslipidemia, and diabetes prevalence rose over time, whereas HF and MI prevalence reduced.

The lifetime risk of AF at the age of 45 between 2000-2022 was 27.7%, with higher risk observed among men, those with a history of certain cardiovascular conditions, and individuals with higher socioeconomic status. From 2000-2010 to 2011-2022, there was an absolute increase in lifetime risk from 24.2% to 30.9%. This trend persisted across all subgroups, with slightly higher increases among men, individuals with HF or stroke history, and those without dyslipidemia. At ages 55, 65, and 75, the lifetime risk also showed an upward trajectory, with absolute increases between the two periods.

Among individuals diagnosed with AF, HF was the most common complication, with a lifetime risk of 41.2%, followed by stroke (21.4%), MI (11.5%), and diagnosed systemic embolism (1.8%). Men generally faced higher risks of HF and MI compared to women, while women had a higher risk of stroke post-AF. History of certain cardiovascular conditions significantly increased the risk of HF post-AF. Over time, a slight decrease in the lifetime risks of stroke (-2.5%) and MI (-3.9%) was observed.

The study reports the temporal patterns in lifetime risks associated with AF and its subsequent complications for the first time. However, the study is limited by its potential underestimation of incident events due to a lack of differentiation between AF and atrial flutter and the absence of data on lifestyle factors and causes of death, among others.

Conclusion

The present Denmark-wide study reveals a concerning trend: the lifetime risk of AF has increased from one in four to one in three over the past two decades. HF emerged as the most common complication following AF, with a lifetime risk twice that of stroke. While there were slight improvements in the lifetime risks of stroke, ischemic stroke, and MI after AF, the rates remained high. These findings highlight the urgent need for effective strategies to prevent HF and stroke in patients with AF.