title: Risk of new-onset atrial fibrillation in elderly patients with the overlap syndrome: a retrospective cohort study.
abstract: OBJECTIVE
  Co-existence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) is referred to as overlap syndrome. Overlap patients have greater degree of hypoxia and pulmonary hypertension than patients with OSA or COPD alone. Studies showed that elderly patients with OSA alone do not have increased risk of atrial fibrillation (AF) but it is not known if overlap patients have higher risk of AF. To determine whether elderly patients with overlap syndrome have an increased risk of AF.
  
  
  METHODS
  In this single center, community-based retrospective cohort analysis, data were collected on 2,873 patients > 65 years of age without AF, presenting in the year 2006. Patients were divided into OSA group (n = 60), COPD group (n = 416), overlap syndrome group (n = 28) and group with no OSA or COPD (n = 2369). The primary endpoint was incidence of new-onset AF over the following two years. Logistic regression was performed to adjust for heart failure (HF), coronary artery disease, hypertension (HTN), cerebrovascular disease, cardiac valve disorders, diabetes mellitus, hyperlipidemia, chronic kidney disease (CKD) and obesity.
  
  
  RESULTS
  The incidence of AF was 10% in COPD group, 6% in OSA group and 21% in overlap syndrome group (P < 0.05). After adjusting for age, sex, HF, CKD, and HTN, patients with overlap syndrome demonstrated a significant association with new-onset AF (OR = 3.66, P = 0.007). HF, CKD and HTN were also significantly associated with new-onset AF (P < 0.05).
  
  
  CONCLUSIONS
  Among elderly patients, the presence of overlap syndrome is associated with a marked increase in risk of new-onset AF as compared to the presence of OSA or COPD alone.
authors.affiliation: The Henry Low Heart Center, Hartford Hospital, B-1010, 80 Seymour Street, Hartford, CT 06102, USA.
authors.forename: Harsha V
authors.initials: HV
authors.lastname: Ganga
authors.forename: Sanjeev U
authors.initials: SU
authors.lastname: Nair
authors.forename: Venkata K
authors.initials: VK
authors.lastname: Puppala
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Miller
keywords: Atrial arrhythmias; Elderly patients; Obstructive lung disease; Sleep apnea