Background

Chronic obstructive pulmonary disease (COPD) has been found to be independently associated with atrial fibrillation (AF). We aim to assess the impact of COPD on patients with AF, as data is limited on the effects of co-existence of these two conditions on inpatient mortality, length of stay (LOS) and hospital costs.

Methods

This is a retrospective cohort study using the 2004-2014 National Inpatient Sample (NIS) of adult patients hospitalized with AF as the admitting diagnosis, and COPD as the secondary diagnosis based on ICD-9 codes. Inclusion criteria was age> 18 years. Our primary outcome was inpatient mortality and our secondary outcomes were mean total hospital costs and mean length of stay (LOS). Multivariate logistic regression was used to adjust for potential confounders including age, gender, race, socioeconomic status, Charlson Comorbidity Index, hospital location, hospital region, teaching status, and hospital size. STATA 13.0 was used for data analysis.

Results

1,012,346 admissions of patients with AF were identified, of which 521,896 patients had a concomitant diagnosis of COPD (48% were females). The mean age was 69.4 years in patients with AF alone and 72.9 years in patients with AF and COPD (p< 0.01). After adjustment for the above factors, patients with AF and COPD had higher inpatient mortality compared to patients with AF alone (OR: 1.90; p< 0.01). Patients with AF stayed in the hospital fewer days than patients with AF and COPD (3.3 days vs. 4.4 days; p< 0.01). Hospitalizations for patients with AF alone cost 7963 USD compared to 9311 USD for patients with AF and COPD.

Conclusion

The two disease processes of AF and COPD are vastly different, yet when combined seem to have a compounded negative effect on patients in inpatient mortality, LOS and total hospital costs. Mechanisms and pathophysiology behind decreased oxygenation, hypercapnia, pulmonary hypertension, diastolic dysfunction and inflammation in COPD patients may be associated with these more severe outcomes in patients who also have AF. Further studies need to be conducted that delineate the association between COPD and AF.