Hospital Mortality for Patients With A-fib Higher in Rural Areas

Patients with A-fib who are admitted to US hospitals in rural areas are slightly more likely to die before discharge than those admitted to urban centers, an observational study suggests.

The rate of in-hospital mortality was 1.3% in rural centers and 1.0% in urban centers, a difference that was significant after multivariable adjustment (OR 1.17; 95% CI 1.04-1.32), lead author Wesley O’Neal, MD (Emory University School of Medicine, Atlanta, GA), and colleagues report in a study published online December 11, 2017, ahead of print in Heart Rhythm.

O’Neal told TCTMD that whether such a difference is clinically meaningful remains to be debated.

“I think largely what this does is it generates other hypotheses for potential differences that exist in the care of people who have A-fib in urban versus rural environments,” he said. “It definitely needs to be looked at a little further with a little more scrutiny, but overall I would view these more as hypothesis-generating results than the be-all end-all.”

Prior research has shown that cardiovascular outcomes are worse in rural versus urban hospitals, but whether a similar disparity would be seen for in-hospital mortality in patients with A-fib, which has declined in recent years, was unclear.

To find out, O’Neal and colleagues examined data from the National Inpatient Sample on 248,731 patients with a primary discharge diagnosis of atrial fibrillation between 2012 and 2014; 88% of patients were treated at urban hospitals, and the rest were admitted to rural centers.

The elevated mortality risk seen at rural centers was consistent in a propensity-matched analysis, across subgroups defined by sex, race, and region, and in an analysis that accounted for greater use of direct external electrical cardioversion and catheter ablation at urban centers.

“This finding has important implications for clinical care, as we have identified a group of patients in which hospital outcomes vary greatly by urban-rural status,” O’Neal et al write. “Therefore, hospitalization for AF possibly represents an area for practice improvement in rural hospitals.”

Why Do Rural Patients Fare Worse?

O’Neal said it’s unclear why in-hospital mortality would be higher in rural hospitals, but pointed to differences in practice—in particular, greater use of external electrical cardioversion and catheter ablation at urban centers—as the most likely explanation.

“To me, that suggests likely that there’s more specialized care, more electrophysiologists, and more doctors who are comfortable handling patients who are admitted for arrhythmia conditions such as A-fib in urban centers versus rural,” he said. O’Neal noted, however, that the claims data forming the basis of the study prevented a more detailed look into what’s driving the mortality difference.

Variation in the quality of care for heart failure, which was the most common secondary diagnosis in this study in both urban and rural hospitals, could be another reason for the urban-rural divide in in-hospital mortality, O’Neal et al add.

“Further research is needed to understand this finding and to develop targeted strategies to reduce mortality in patients admitted for AF in rural hospitals,” they conclude.

Mind the Limitations

In an accompanying editorial, Thomas Deering, MD, and Ashish Bhimani, MD (Piedmont Heart Institute, Atlanta, GA), say, “Although this study advances our understanding about how the locus of healthcare delivery can influence outcomes, the usual intrinsic limitations associated with a claims-based analysis make it necessary to be cautious to avoid interpreting the reported findings too broadly.” They point to the lack of detailed clinical information and highlight issues involving the definition of urban and rural centers.

Regarding the assertion that the observed mortality differences between rural and urban hospitals are related to differences in quality of care, Deering and Bhimani note that evidence is mixed in terms of a gap between urban and rural populations. “More detailed information, analyzed from a number of perspectives, will be needed to shed more light on this topic,” they say.

Moreover, the editorialists state that the small absolute difference in mortality observed in the study poses a challenge to assessing the clinical significance of the finding.

“We believe it is fair to state that [the] study raises more important clinical and epidemiologic questions than it provides answers,” Deering and Bhimani say. “Although rural AF patients had a higher mortality rate than urban AF patients, information about the many operative factors (eg, associated comorbidities and their severity, access to care, patient lifestyle decisions, patient compliance, physician adherence to diagnostic and therapeutic guideline recommendations), which may have contributed to producing the observed outcomes, remains unknown. Accordingly, claims-based analyses such as these should be viewed as hypothesis-generating instead of categorical in nature.”

Ultimately, though, “the electrophysiology and medical communities should look at the findings presented in this study as a motivational call to initiate prospective studies with the goal of identifying gaps in AF care, which can then be used to create effective healthcare policies designed to reduce AF-related mortality,” they conclude.