Recent trends and future projections in atrial fibrillation epidemiology: a european population-based study

Abstract Background Atrial fibrillation (AF) is a major public health challenge, associated with substantial morbidity, disability, and mortality. Its burden is rising worldwide, with marked regional variability. Contemporary, population-based data in South-European Mediterranean settings are scarce. Age-adjusted estimates of AF prevalence and incidence, temporal trends, and credible projections are needed to inform public screening and prevention policies. Purpose To provide a contemporary, age-adjusted, population-based portrait of AF in a large Mediterranean population by estimating prevalence and incidence, quantifying recent trends, and generating projections relevant for public health planning. Methods We conducted a population-based observational study using validated primary care electronic health records from the System for the Development of Research in Primary Care (SIDIAP), covering >80% of the Catalan population. Adults aged ≥40 years were followed from 2009–2021. We assessed AF prevalence and incidence by age and sex, summarized temporal trends using estimated annual percentage change (EAPC), estimated lifetime risk at age 40 and projected AF burden to 2050 using official population forecasts for Catalonia and Spain. Results In 2009, the cohort included 2,878,194 adults ≥40 years; 91,423 had AF. By 2021, AF cases rose 62% to 148,009. Between 2009 and 2021 AF prevalence increased 40%, from 3.18% to 4.46% (p<0.001; EAPC 2.62%, 95% CI 2.07–3.17). The increase in AF prevalence was significant across all 5-years age groups (EAPC >1% in every group), with the largest relative rises in patients aged <50 years (+100% at 40–44; +75% at 45–49). In absolute terms, AF prevalence was maximal in older patients (14.1% in those ≥70 years in 2021). Men had higher AF prevalence every year and a greater relative increase over follow-up (50% vs 30%, p<0.001), despite being, on average, younger. In 2021, prevalence was 4.87% in men vs 4.07% in women (p<0.001). AF incidence increased with age—from 0.25 (95% CI 0.20–0.30) to 38.21 (95% CI 36.13–40.37) per 1,000 person-years at ages 40–44 and >90 years, respectively—and was consistently higher in men, yet remained stable between 2009 and 2021 (EAPC −0.26%; 95% CI −0.93 to 0.41). Lifetime risk of AF at age 40 was 38.0% (95% CI 37.9–38.2), higher in men than women (44.4% vs 33.1%, p<0.001). Applying 2021 age-specific prevalence to 2050 population projections, AF burden is expected to approximately double, reaching 346,302 individuals in Catalonia and 2,236,072 in Spain—equivalent to 6.3% and 6.5% of those >40 years, respectively. Conclusions In the largest population-based evaluation of AF epidemiology in a Mediterranean population to date, AF prevalence rose by >40% over 13 years. Projections indicate a doubling of AF cases by 2050. The fastest relative growth in younger adults underscores the need for targeted prevention and aggressive risk-factor control to curb future AF burden.