The prevalence of atrial fibrillation (AF) is projected to double over the next 30 years and has been linked to significant morbidity and mortality. The current annual cost of caring for AF is about $6 billion in the United States, with most of this cost resulting from inpatient care. Research has suggested that costs are likely to rise in the future because the risk of developing AF increases with age. “With greater recognition that the burden of AF is increasing, more attention is being paid to identifying factors that drive hospitalizations for these patients,” says Benjamin A. Steinberg, MD, MHS.
Addressing Frequency & Predictors
Although it is well known that AF admissions are common, few studies have assessed all-cause and cause- specific hospitalization rates among U.S. patients with AF. In a study published in the American Heart Journal , Dr. Steinberg and colleagues sought to assess the frequency and predictors of hospitalization in patients with AF. The study group used data from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF), a prospective observational study of U.S. outpatients with AF.
“ORBIT-AF involved many thought leaders in cardiology throughout the country,” explains Dr. Steinberg. “It included AF patients who were being managed by primary care physicians, cardiologists, and/or electrophysiologists.” The researchers used ORBIT-AF data from more than 9,400 participants with 1-year follow-up to assess the burden of hospitalization in patients with AF and described the cause-specific rates of hospitalizations. They also sought to identify baseline factors that significantly predicted cause- specific hospitalizations in patients with AF.
Examining Key Findings
The study by Dr. Steinberg and colleagues found that hospitalizations among patients with AF were common. “Nearly one in three patients with AF was hospitalized within 1 year,” says Dr. Steinberg. Of these patients, 21% had only one hospitalization, but more than 10% had two or more visits to the hospital during the follow-up period (Figure 1). The study also found that most hospitalizations in patients with AF were for cardiovascular causes. When compared with those who were not hospitalized, those who were had a higher likelihood of having concomitant heart failure (HF), higher average CHADS 2 scores, and more symptoms (Figure 2).
In multivariable analyses, severe HF, AF symptoms, and elevated heart rate at baseline were identified as significant predictors of all-cause and cardiovascular hospitalization. “Our observation regarding patients with highly symptomatic AF and HF are particularly important,” Dr. Steinberg says. “These individuals are at high risk for hospitalization, indicating that this is a dangerous combination. They account for a disproportionate burden of hospitalizations when compared with other subgroups. These findings underscore the urgent need and ongoing efforts to improve HF treatment and reduce the frequency of recurrent hospitalizations.”
Dr. Steinberg points out that hospitalization was also common in patients with AF who did not have HF, with more than 32 events per 100 patient-years. “Even when we modeled predictors of hospitalization only among AF patients without HF, symptom status remained a major driver of events,” he says. “Clinicians who are evaluating these patients should recognize that symptom status is a marker of high risk for hospitalization.” Dr. Steinberg adds that patients with higher heart rates at baseline were also more likely to be hospitalized—regardless of their HF status—after adjusting for symptom class.
Reducing Healthcare Use
Data from the study provide a more detailed look at AF and associated hospitalizations, but more work is needed to find strategies that aggressively manage patients with symptomatic and uncontrolled AF in order to improve clinical outcomes. “It’s clear that more research on the symptomatic management of AF is needed, but there is hope that such investigations will reduce the number of hospitalizations for these patients in the future,” says Dr. Steinberg. “Our findings highlight the extensive, prevalent comorbidity that occurs in patients with AF and the associated risks.”
There are potential opportunities to intervene when caring for patients with significant AF burden, particularly those who are hospitalized. “Many patients have other illnesses that increase their risk of adverse events and complicate the management of AF,” Dr. Steinberg says. “When caring for these individuals, we should consider AF in the context of other medical problems, especially HF, blood pressure, and diabetes. Keeping these other factors in mind may help us achieve the over-arching goal of minimizing morbidity and mortality from all causes by using proven, evidence-based therapies. There is still plenty of room for improvement in the care of this patient population.”
Steinberg BA, Kim S, Fonarow GC, et al. Drivers of hospitalization for patients with atrial fibrillation: results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Am Heart J. 2014;167:735-742. Available at: http://www.ahjonline.com/article/S0002-8703(14)00075-1/fulltext.
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