Purpose: In the United States, about 87% of stroke is ischemic stroke. Atrial fibrillation (AF) is a major risk factor for and associated with more severe, ischemic stroke. While stroke mortality and incidence rates as well as the impact of AF on stroke are well documented, the influence of AF on the cost of stroke at national level is unknown. We estimated the AF-associated costs among elderly population (age ≥ 65 years) with ischemic stroke.
Methods: Using 2010 Medicare Provider Analysis and Review data, we identified all hospitalizations with a primary diagnosis of ischemic stroke by International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes of 433, 434, and 436. After excluding the hospitalizations with no racial information and those with 30 or more days of hospital stays, we estimated the cost associated with AF (ICD-9-CM code 427.31, 427.32) using multivariate regression models for three population groups: National, stroke belt (an 8-state region of southeastern US), and non-stroke belt. From a societal perspective, we used total charge as the total cost for the hospital stays. We explored the association between the cost and age, sex, race, initial admission status, respectively.
Results: Among 257,595 hospitalizations with ischemic stroke, 23.5% of them had AF. The mean cost was $34,901, of which $4979 (95% confidence interval [CI], $4649-$5309) was AF-associated. Compared to the rest of the country, the cost of hospitalizations in stroke belt was $7892 lower (95% CI, $7611-$8173). After controlling for potential confounders, AF associated cost was $3436 (95% CI, $2861-$4010) in stroke belt and $5169 (95% CI, $4788-$5550) in non-stroke belt. Both mean cost and AF-associated costs decreased with age. Hospitalizations of male patients had higher mean cost, but lower AF-association cost than those of female patients. Hospitalizations of African American patients had both higher mean cost and AF-associated costs than those of whites.
Conclusions: The hospitalization cost for patients with ischemic stroke was high, and AF further increased the costs. While there has been a persistent high stroke mortality rate in the stroke-belt, both the mean and AF-associated costs of the hospitalizations in non-stroke belt were substantially higher than those in stroke-belt. Age, gender, and race are major determinants of the cost.