title: Evaluation of quality improvement interventions for reducing adverse outcomes of carotid endarterectomy.
abstract: BACKGROUND
  Clinical and health services interventions should be evaluated for their effectiveness.
  
  
  OBJECTIVE
  The objectives of this study were to evaluate the effectiveness of quality improvement interventions for reducing the adverse outcome of the carotid endarterectomy (CEA) procedure, and to study the relationship between pre- and postintervention 30-day mortality and stroke rates. These interventions were implemented in 1997-1998 by the Peer Review Organizations (PRO) for 7 states.
  
  
  METHODS
  In a quasiexperimental study, a control state was matched with each of the 7 intervention states. Pretest-posttest analyses compared the preintervention outcome rates in each intervention and control state with the corresponding postintervention rates. In a time (1991-2001) series analysis, the trends in the preintervention 30-day, 7-state mortality in intervention and control states were compared with the trends in the corresponding postintervention rates.
  
  
  METHODS
  We studied Medicare beneficiaries aged 65 years and older who had a CEA procedure in 14 states during 1991-2001.
  
  
  RESULTS
  There was no correlation between the state-specific, preintervention 30-day mortality and the corresponding postintervention mortality. After interventions, there was no significant decline in 30-day mortality in any intervention or control state, or in all 7 intervention states combined or all control states combined. Similarly, the 30-day stroke rate did not decrease after interventions in any state. The trend in the 7-state, 30-day mortality also did not show further decline after interventions.
  
  
  CONCLUSIONS
  After PRO interventions, the post-CEA 30-day mortality and stroke rates did not decrease in any individual intervention state or in all states combined.
authors.affiliation: U S Department of Health and Human Services, Centers for Medicare & Medicaid Services, Kansas City, Missouri 64106, USA. ksheikh@cms.hhs.gov
authors.forename: Kazim
authors.initials: K
authors.lastname: Sheikh
authors.forename: Claudia
authors.initials: C
authors.lastname: Bullock
authors.forename: Steven D
authors.initials: SD
authors.lastname: Preston
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016894:Endarterectomy, Carotid / Q000009:adverse effects / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D006278:Medicare; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D011366:Professional Review Organizations; D015397:Program Evaluation; D011785:Quality Assurance, Health Care; D012044:Regression Analysis; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control*; D014481:United States / Q000453:epidemiology