Epidemiology of atrial fibrillation in patients hospitalized in a large hospital.

The prevalence of atrial fibrillation varies widely depending on the population studied. To understand the incidence of atrial fibrillation and its significance in relation to other diseases, 3 years (1989 through 1991) of consecutive hospital discharges from the neurology and internal medicine services at Henry Ford Hospital were studied. Of the 26,964 patients who qualified for analysis, 1346 (5%) had atrial fibrillation as 1 of their 5 recorded discharge diagnoses. Comparing the group without atrial fibrillation to those with atrial fibrillation, there were 51% males in both groups (p = 0.88). African-Americans comprised 33% of the patients with atrial fibrillation and 50% of the patients without atrial fibrillation (p < 0.001). The average age of those with atrial fibrillation was 72 +/- 13 years, and 58 +/- 18 years for those without atrial fibrillation (p < 0.001). Length of hospital stay was 9.6 +/- 8.6 days with atrial fibrillation and 7.6 +/- 9.2 days for those without atrial fibrillation (p < 0.001). After adjusting for the effects of age, significant positive associations were noted in those patients with atrial fibrillation whose co-existing condition was either stroke, heart failure, myocardial infarction, hyperthyroidism, or mitral valve disease. There was also a significant negative relationship between hypertension and atrial fibrillation. The most common of the 5 discharge diagnoses observed in patients with atrial fibrillation was congestive heart failure (40%), followed by hypertension (23%) and ischemic heart disease (21%). The existence of a comorbid disease in patients with atrial fibrillation is important, as it can influence medical management and prognosis.