title: The significance of atrial fibrillation in patients aged ≥ 55 years undergoing abdominal surgery.
abstract: BACKGROUND
  The Institute of Medicine has identified atrial fibrillation (AF) among national priorities for research. We examine the incidence of AF and its association with outcomes of patients undergoing abdominal surgery.
  
  
  METHODS
  Patients ≥ 55 years who underwent abdominal surgery captured in a State Inpatient Database, 2008-2010. Three patient groups were created: (1) No diagnosis of AF (No-AF), (2) Pre-existing AF (Hx-AF), and (3) New-onset AF (New-AF). Outcomes were analysed using bivariate and multivariate methods.
  
  
  RESULTS
  AF incidence among 116,477 patients was 8.6 %; approximately one in four patients aged ≥ 85 years had AF. 26.6 % of patients with AF experienced New-AF; the latter was more likely after pancreas resection (43.0 %) and least common after cholecystectomy (20.2 %). Complications (71.1, 47.3 vs. 26.5 %), mortality (8.0, 5.7 vs. 2.0 %), longer hospital stays (8.8, 5.6 vs. 3.8 days), and higher hospitalization cost ($41,427, $26,312 vs. $18,310) were more likely in patients with AF (New-AF, Hx-AF vs. No-AF respectively) (all p < 0.001). After adjustment, New-AF was among factors independently associated with mortality (OR 2.0, 95 % CI 1.7-2.4, p < 0.001); each case of New-AF increased cost of care by $4,482. Factors independently associated with New-AF included ≥ 1 complication, electrolyte imbalance, and procedure-type. Whereas 2.0 % of patients who developed New-AF were admitted from a long-term care facility, 23.8 % of patients with New-AF were discharged to a long-term care facility.
  
  
  CONCLUSIONS
  AF is common among abdominal surgery patients, particularly the elderly; New-AF is a serious, potentially avoidable adverse event that could serve as an important quality of care indicator for abdominal surgery patients.
authors.affiliation: Department of General Surgery, Stanford University, Palo Alto, CA, USA.
authors.forename: Hadiza S
authors.initials: HS
authors.lastname: Kazaure
authors.forename: Sanziana A
authors.initials: SA
authors.lastname: Roman
authors.forename: Douglas
authors.initials: D
authors.lastname: Tyler
authors.forename: Julie A
authors.initials: JA
authors.lastname: Sosa
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology*; D015897:Comorbidity; D004066:Digestive System Diseases / Q000453:epidemiology* / Q000601:surgery*; D005260:Female; D006801:Humans; D015994:Incidence; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D014481:United States