Increased mortality in patients with secondary diagnosis of atrial fibrillation: Report from Chinese AF registry.

Background: The relationship between mortality and the primary diagnosis in AF patients is poorly recognized. The purpose of the study is to compare the differences on mortality in patients with a primary or secondary diagnosis of AF and to identify risk factors amenable to treatment.

Methods: This was a prospective cohort study using data from the Chinese AF registry. For admitted patients, a follow-up was completed to obtain the outcomes during 1 year.

Results: A total of 2015 patients with confirmed AF were included. AF was the primary diagnosis in 40.9% (n = 825) of them. 78.9% (n = 939) of the secondary AF diagnosis patients and 55.5% (n = 458) of the primary AF diagnosis patients were sustained AF. Compared with primary AF diagnosis group, the secondary AF diagnosis group was older with more comorbidities. At 1 year, the unadjusted mortality was much higher in the secondary AF diagnosis groups compared with the primary AF diagnosis groups. In Cox regression analysis with adjustment for confounding factors, patients with secondary AF diagnosis were associated with an increased mortality (relative risk 1.723; 95% CI: 1.283 to 2.315, p < .001). On multivariate analysis, age ≥ 75, LVSD, COPD, and diabetes were independent predictors of mortality in patients with primary AF diagnosis, while for the secondary AF diagnosis group, the risk factors were age ≥ 75, heart failure, and previous history of stroke.

Conclusions: Patients presenting to ED with secondary diagnosis of AF were suffering from higher mortality risks compared with primary AF diagnosis patients. Physicians should distinguish these two groups in clinical practice.