Clinical characteristics of atrial fibrillation in nonagenarian population and relationship with mortality.

Background: There is a considerable amount of literature available on well-known risk factors for atrial fibrillation (AF); however, available data specifically focused on the ninth decade are scarce. The main objective of this study was to assess the demographic and clinical characteristics of AF and sinus rhythm in a nonagenarian population.

Methods: All individuals aged >90 years who were admitted to the Cardiology outpatient clinic between April 2018 and January 2019 were enrolled in the study. The demographic and clinical characteristics of all patients were recorded. All deaths that occurred during the two-year follow-up period were recorded.

Results: In total, 112 nonagenarian individuals were included in the study. Of these patients, 50 (44.6%) had AF. The groups showed similarities in demographic and clinical characteristics. During a mean follow-up period of 596±44 days, 39 patients (78%) in the AF group and 35 patients (56.5%) in the sinus group died. Patients with AF showed a lower overall survival distribution than those with sinus rhythm (P=0.005, log-rank test χ=7.734). AF was associated with an increased risk of mortality (P=0.002, hazard ratio [HR] =2.104, 95% confidence interval [CI] = 1.326-3.339) in multivariate Cox regression analysis, while waist circumference and total cholesterol (P=0.003, HR=0.969, 95% CI=0.949-0.989 and P=0.046, HR=0.993, 95% CI=0.986-1.000, respectively) showed a decreased risk of mortality.

Conclusions: Atrial fibrillation is very common in individuals over the age of 90 years (44.6%). Well-known risk factors do not appear to be effective in this age group, and AF is associated with a 2.1-fold increase in the risk of mortality.