Introduction: Recent studies suggest patients with atrial fibrillation (AF) who suffer from obstructive sleep apnea (OSA) have varied responses to ablative procedures, as AF substrates in these patients might be different from patients with primary AF. We investigated the effects of coexistence of these two conditions on mortality and hospital costs in patients who underwent AF ablation. We hypothesized there would be significant differences in mortality between the two populations.
Methods: This is a retrospective cohort study using the 2013 National Inpatient Sample (NIS) of males and females over 18 hospitalized with AF who underwent ablation, based on ICD-9 codes. The population was divided into patients with and without a concomitant diagnosis of OSA. The primary outcome was all cause inpatient mortality and secondary outcomes were mean length of stay (LOS), and total hospital costs. The multivariate logistic regression model was used to adjust for potential confounders including age, gender, race, hospital location, socioeconomic status, hospital region, hospital bed size, hospital teaching status, primary insurance and the Charlson Comorbidity index. STATA 13.0 was used for data analysis.
Results: 73,729 admissions were identified with the primary diagnosis of AF undergoing ablation procedures, out of which 9,735 (13.2%) had a diagnosis of OSA as well. Females numbered 26,314 (35.7%) of the total population, 2,472 (25.4%) of patients with OSA, and 23,482 (37.3%) of patients without OSA. The mean age for patients with and without OSA was 62 and 65.8 years, respectively. Adjusted odds ratio for all-cause inpatient mortality was 0.55 in patients with OSA compared to those without (p=0.017). LOS in patients with OSA and without OSA was 3.25 and 3.18 days (p <0.001), respectively. Total hospital cost for patients with OSA was $2,771 higher compared to those without OSA ($24,337 vs $21,566; p <0.001).
Conclusion: Patients who undergo AF ablation with OSA have lower inpatient mortality compared to those with only AF. This might point toward a different pathophysiology for AF in patients who suffer from OSA, which portends a better prognosis compared to patients with primary atrial fibrillation not associated with OSA.