Contemporary trends in incident ischaemic stroke, intracranial haemorrhage, and mortality in individuals with atrial fibrillation.

Background: The prognosis for atrial fibrillation (AF) patients is based on data that is decades old. Given evolving standards of clinical practice, we sought to evaluate temporal trends in clinically important outcomes among patients with AF.

Methods and results: California's Department of Health Care Access and Information databases were used to identify adults aged ≥18 years with AF receiving hospital-based care in California. We compared three time-periods: 2005-2009, 2010-2014, and 2015-2019. International Classification of Diseases codes were used to identify chronic diseases and acute events. The outcomes were incident ischaemic stroke, intracranial haemorrhage, and overall mortality. We included 2 009 832 patients with AF (52.7% males, 70.7% Whites, and mean age of 75.0 years), divided in three cohorts: 2005-2009 (n = 738 954), 2010-2014 (n = 609 447), and 2015-2019 (n = 661 431). Each outcome became substantially less common with time: compared with 2005-2009, AF patients diagnosed in 2015-2019 experienced a 34% (adjusted hazard ratio [HR] 0.66, 95% confidence interval 0.64-0.69), 22% (HR 0.78, 0.75-0.82), and 24% (HR 0.76, 0.75-0.77) reduction in risk of incident ischaemic stroke, intracranial haemorrhage, and mortality, respectively. Between 2005-2009 and 2015-2019, patients aged ≥65 years experienced more reductions in each outcome compared with younger patients (P < 0.001 for all), and declines in each outcome were significantly lower for Hispanics and Blacks compared with white patients.

Conclusion: The risks of stroke, intracranial haemorrhage, and death have significantly declined among AF patients, although differences in the magnitude of improvement of these outcomes by demographic groups were observed. Commonly described estimates of the prognosis for AF patients should be updated to reflect contemporary care.