title: Annual all-cause healthcare costs among influenza patients with and without influenza-related complications: analysis of a United States managed care database.
abstract: BACKGROUND
  Several studies have reported that patients with influenza have a high risk of developing complications such as secondary infections, exacerbation of cardiovascular conditions and asthma. However, limited data exists on the healthcare cost burden for influenza patients with and without influenza-related complications.
  
  
  OBJECTIVE
  We compared healthcare utilization and costs among influenza patients with related complications versus patients without complications.
  
  
  METHODS
  In this retrospective database analysis (LifeLink database: 1998-2009) of a US managed care database, we selected patients diagnosed with influenza during influenza seasons and categorized them as complicated or uncomplicated based on the presence or absence of a diagnosis for a related complication in the year following their influenza diagnosis. Multivariable regression analyses were conducted to compare all-cause utilization and costs (adjusted to 2009 US dollars) between the two groups.
  
  
  RESULTS
  We identified 54,469 patients of which ~65 % had evidence for at least one complication. Patients with complicated influenza had a 1.5-fold higher rate of inpatient utilization compared with uncomplicated cases (p < 0.001). Significantly higher covariate-adjusted predicted mean annual costs were also observed among complicated influenza patients across all care (p-values <0.001 for all comparisons).
  
  
  CONCLUSIONS
  Healthcare costs were twice as high among influenza patients with complications versus those without, with inpatient and outpatient services being the primary cost drivers. Now with the universal recommendation for seasonal influenza vaccination for all individuals ≥6 months of age, improvement in coverage rates may help reduce the healthcare utilization and costs associated with influenza and associated complications.
authors.affiliation: RTI Health Solutions, 200 Park Offices Drive, Post Office Box 12194, Research Triangle Park, NC 27709, USA. sjkarve@rti.org
authors.forename: Sudeep
authors.initials: S
authors.lastname: Karve
authors.forename: Derek
authors.initials: D
authors.lastname: Misurski
authors.forename: Guillermo
authors.initials: G
authors.lastname: Herrera-Taracena
authors.forename: Keith L
authors.initials: KL
authors.lastname: Davis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000191:economics / Q000706:statistics & numerical data; D015331:Cohort Studies; D019992:Databases as Topic; D005260:Female; D017048:Health Care Costs; D006801:Humans; D007251:Influenza, Human / Q000191:economics* / Q000628:therapy*; D007297:Inpatients / Q000706:statistics & numerical data; D008137:Longitudinal Studies; D008297:Male; D008329:Managed Care Programs / Q000191:economics*; D008875:Middle Aged; D012189:Retrospective Studies; D014481:United States; D014600:Utilization Review; D055815:Young Adult