Hospitalization and costs for atrial fibrillation spiked between 2000 and 2010 in the U.S., particularly among octogenarians. The authors of the analysis published online May 19 in Circulation called the trends alarming.

Nileshkumar J. Patel, MD, of Staten Island University Hospital in New York, and colleagues conducted a cross-sectional study of atrial fibrillation trends over time using the Nationwide Inpatient Sample (NIS) database from 2000 to 2010. The NIS includes discharge data from more than 1,200 hospitals in 45 states.

The evaluation assessed the burden of atrial fibrillation-related hospitalization, looking at comorbidities, demographics, mortality, length of stay and cost of care. They focused on patients 18 years old and older with a primary diagnosis of atrial fibrillation. To calculate costs they linked NIS data with cost-to-charge ratios in the Healthcare Cost and Utilization Project, adjusted for inflation.

There were almost 4 million hospitalizations for atrial fibrillation during the study period, and the numbers increased steadily each year. Hospitalizations grew from 312,926 in 2000 to 409,854 in 2010. Patients were mostly white and elderly. Medicare or Medicaid footed the bill for 70 percent of hospitalizations.

The hospitalization rate increased from 1,552 to 1,812 per million per year, for a relative increase of 14.4 percent. Among patients 80 years old or older, the relative increase was 15.2 percent.

In-hospital mortality decreased between 2000 and 2010, from 1.2 percent to 0.9 percent. Mortality was highest in patients 80 and older, at 1.9 percent. The prevalence of comorbidities also increased over time. In patients with heart failure who were hospitalized for atrial fibrillation, the mortality rate was 8.2 percent.

The mean cost for an atrial fibrillation hospitalization was $6,410 in 2001 and $8,439 in 2010, for a relative increase of 24 percent, despite the fact that length of stay did not change over the study period. Mean cost of care for an atrial fibrillation hospitalization and a comorbidity was highest with heart failure, which Patel et al calculated reached $33,161.

They determined that patients 80 and older accounted for the largest number of admissions per million population for any age group, growing from 9,361 per million in 2000 to 11,045 per million in 2010. “These figures are alarming as the number of persons 80 years and more is expected to increase from 11.4 million in 2008 to 19.5 million in 2030; which in turn will lead to an enormous increased burden on the public health system and associated cost of care.”

By using the NIS administrative data, they could not discriminate atrial fibrillation by type or identify readmissions. They added that they may have underestimated atrial fibrillation if patients were categorized by another condition such as heart failure as a primary diagnosis.