Hospitalization for Atrial Fibrillation

Abstract & Commentary

Synopsis: The frequency with which patients are hospitalized for atrial fibrillation is increasing dramatically with a large proportion of the increase due to an increased number of elderly patients in the population. Part of this increase may also be due to changes in management strategies for atrial fibrillation. Inpatient observation for initiation of antiarrhythmic therapy or for anticoagulation is now commonly recommended, particularly in elderly patients.

Source: Wattigney WA, et al. Circulation. 2003;108:711-716.

Wattigney and associates from the centers for Disease Control conducted a survey of hospitalizations related to atrial fibrillation during the period of 1985-1999. Wattigney et al use the National Hospital Discharge Survey (NHDS), which includes demographic and medical information abstracted from medical records of inpatients selected from a nationally representative sample of nonfederal, short-stay hospitals in the United States. Records were limited to patients 35 years of age or older with atrial fibrillation recorded as 1 of up to 7 discharge diagnoses. Data for patients with atrial fibrillation reported as both a primary diagnosis and as a secondary diagnosis were included in this analysis. These data were combined with census bureau estimates to calculate age- and sex-specific prevalence of hospitalization for atrial fibrillation per 10,000 members of the US population.

The estimated number of hospitalizations and unadjusted prevalence with atrial fibrillation as the principle diagnosis increased from 154,086 in 1985 to 376,487 in 1999. This was a 144% relative increase. In the same period, hospitalization that listed atrial fibrillation as any of the 7 diagnoses increased from 787,750 to 2,283,673 (a 190% relative change). Although women outnumbered men in the absolute numbers of atrial fibrillation hospitalizations, the age-standardized prevalence of hospitalizations for atrial fibrillation was consistently higher among men than women. Analysis for the data using age-specific prevalence showed an increase in atrial fibrillation hospitalization with increasing age. There was only a minor increase over time among patients aged 35 to 54 years but a striking increase in patient groups older than 75 years of age. Most patients with atrial fibrillation during the course of the study were discharged home. However, over time, the percentage of patients discharged home decreased slightly with a corresponding increase in discharges to a long-term care institution. However, Wattigney et al could not determine how many of these patients originated in a long-term care institution and were discharged back to their prior residence. Death was uncommon for discharges in which atrial fibrillation was the primary diagnosis. However, atrial fibrillation as a secondary diagnosis was commonly associated with either stroke, acute myocardial infarction, or congestive heart failure, and case fatality rates were high among patients with these conditions. Particularly among elderly patients, pneumonia was the most common noncardiac principle diagnosis seen in association with atrial fibrillation. Essential hypertension, ischemic heart disease, and congestive heart failure were the most commonly associated cardiac co-morbidities.

Wattigney et al conclude that the frequency with which patients are hospitalized for atrial fibrillation is increasing dramatically with a large proportion of the increase due to an increased number of elderly patients in the population. Part of this increase may also be due to changes in management strategies for atrial fibrillation. Inpatient observation for initiation of antiarrhythmic therapy or for anticoagulation is now commonly recommended, particularly in elderly patients. Wattigney et al argue that better techniques for maintaining sinus rhythm are necessary to counter this trend.

Comment by John DiMarco, MD, PhD

This paper presents interesting data showing the effect of atrial fibrillation on hospitalizations in the US population. It is well known that atrial fibrillation becomes increasingly frequent as patients become older. The data presented here confirm that this aging of the population is reflected in an increase in hospitalization of patients with this arrhythmia.

Wattigney et al are convinced, however, that more aggressive therapy to restore and maintain sinus rhythm in patients with atrial fibrillation, using either ablation, device-based, or pharmacologic approaches, may counter this trend, but this opinion is not supported by recent clinical trials. In fact, in both the AFFIRM trial and the RACE trial, increased rates of hospitalization were seen in patients in whom a rhythm control strategy was used as the primary approach. Part of the reason for this was related to the need for hospitalizations to initiate antiarrhythmic drug therapy, but it is also likely that the common failures of antiarrhythmic therapy led to an acute presentation that required a hospital stay for stabilization. A need for hospitalization might not have been seen if patients had just been maintained on a stable rate control regimen. Unless antiarrhythmic therapy is highly successful and safe, the need for frequent hospitalizations will likely persist. Unfortunately, there have been no major recent breakthroughs in drug therapy for atrial fibrillation, and ablation approaches, though more promising, have not been shown to be highly effective in the elderly patients with advanced disease who account for the majority of hospitalization.

This paper does provide important epidemiologic data about the magnitude of atrial fibrillation in the United States today. What we need now are better solutions.

Dr. DiMarco, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville, is on the Editorial Board of Clinical Cardiology Alert.