title: The healthcare utilization and cost of treating patients experiencing inappropriate implantable cardioverter defibrillator shocks: a propensity score study.
abstract: BACKGROUND
  Inappropriate shocks (IASs) from implantable cardioverter defibrillators (ICDs) are associated with decreased quality of life, but whether they increase healthcare utilization and treatment costs is unknown. We sought to determine the impact of IASs on subsequent healthcare utilization and treatment costs.
  
  
  METHODS
  We conducted a case-control analysis of ICD patients at a single institution from 1997 to 2010 and who had ≥12 months of post-ICD implant follow-up. Cases included all patients experiencing an IAS during the first 12 months after implantation. Eligible control patients did not receive a shock of any kind during the 12 months after implantation. Propensity scores based on 36 covariates (area under curve = 0.78) were used to match cases to controls. We compared the rate (occurrences/person year [PY]) of healthcare utilization immediately following IAS to the end of the 12-month follow-up period to the rate in the no-shock group over 12 months of follow-up. We also compared 12-month postimplant treatment (outpatient clinic, emergency room, and hospitalization) costs in both groups.
  
  
  RESULTS
  A total of 76 patients experiencing ≥1 IAS during the first 12 months after implant (contributing 48 PYs) were matched to 76 no-shock patients (contributing 76 PYs). Cardiovascular (CV)-related clinic visit and hospitalization rates were increased following an IAS compared to those not receiving a shock (4.0 vs 3.3 and 0.7 vs 0.5, respectively, P = 0.02 for both). CV-related emergency room visitation (0.15 vs 0.08) rates were also numerically higher following an IAS, but did not reach statistical significance (P = 0.26). Patients experiencing an IAS accrued greater treatment costs during the 12 months postimplant compared to no-shock patients ($13,973 ± $46,345 vs $6,790 ± $19,091, P = 0.001).
  
  
  CONCLUSIONS
  Recipients of IAS utilize the healthcare system more frequently following an IAS than patients not experiencing a shock. This increased utilization results in higher costs of treating IAS patients during the 12 months postimplant.
authors.affiliation: Division of Cardiology, Section of Arrhythmia Services, Hartford Hospital, Hartford, Connecticut; Scripps Health, Scripps Translational Sciences Institute, La Jolla, California.
authors.forename: Sanjeev P
authors.initials: SP
authors.lastname: Bhavnani
authors.forename: Dalia
authors.initials: D
authors.lastname: Giedrimiene
authors.forename: Craig I
authors.initials: CI
authors.lastname: Coleman
authors.forename: Danette
authors.initials: D
authors.lastname: Guertin
authors.forename: Meena
authors.initials: M
authors.lastname: Azeem
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kluger
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D017147:Defibrillators, Implantable; D004868:Equipment Failure / Q000191:economics*; D005260:Female; D017048:Health Care Costs; D006801:Humans; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D057216:Propensity Score; D012189:Retrospective Studies
keywords: cost; healthcare resources; implantable cardioverter defibrillator; inappropriate shocks; outcomes; quality