title: Medicare HMO penetration and mortality outcomes of ischemic stroke.
abstract: OBJECTIVE
  To examine associations between Medicare health maintenance organization (HMO) penetration and stroke mortality outcomes among older persons.
  
  
  METHODS
  Panel analysis of nationally representative secondary data from 1993 to 1998.
  
  
  METHODS
  The first analysis sample included ischemic stroke hospitalizations among older persons in the Nationwide Inpatient Sample; the second included county-level ischemic stroke deaths in the National Vital Statistics System. The 2 samples were merged with the HMO enrollment data and the 2001 Area Resource File. The 2 outcomes were in hospital death status and county-level population ischemic stroke death rates among older persons; the 2 utilization variables were length of hospital stay for ischemic stroke and proportion of ischemic stroke deaths occurring in hospitals. The 3 key explanatory variables were county-level Medicare total, independent practice association, and nonindependent practice association HMO penetration. Ordinary least squares analysis with hospital or county fixed effects was used in estimation.
  
  
  RESULTS
  Medicare HMO penetration was not associated with the 2 ischemic stroke mortality outcomes (P > .05). Increases in Medicare total and independent practice association HMO penetration were associated with a significant shift in a higher proportion of stroke deaths from hospitals to nursing homes or residences (P < .05). Medicare HMO penetration was negatively associated with length of stay, although this was not statistically significant (P > .05).
  
  
  CONCLUSIONS
  Increased Medicare HMO penetration was associated with a shift in ischemic stroke deaths from hospitals to nonhospital settings. The effect of Medicare HMO penetration on quality of stroke care needs further research.
authors.affiliation: Division of Preventive Medicine, University of Alabama at Birmingham, Deep South Center on Effectiveness at Birmingham VA Medical Center, 35295-4410, USA. jbian@uab.edu
authors.forename: John
authors.initials: J
authors.lastname: Bian
authors.forename: William H
authors.initials: WH
authors.lastname: Dow
authors.forename: David B
authors.initials: DB
authors.lastname: Matchar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications*; D005260:Female; D006279:Health Maintenance Organizations / Q000458:organization & administration*; D006302:Health Services Research; D017052:Hospital Mortality / Q000639:trends*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007193:Independent Practice Associations / Q000706:statistics & numerical data; D038801:International Classification of Diseases; D016018:Least-Squares Analysis; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D006278:Medicare / Q000458:organization & administration*; D015999:Multivariate Analysis; D009462:Neurology; D009735:Nursing Homes / Q000706:statistics & numerical data; D017063:Outcome Assessment, Health Care; D011159:Population Surveillance; D020379:Risk Adjustment; D020521:Stroke / Q000209:etiology / Q000401:mortality; D014481:United States / Q000453:epidemiology; D000078329:Workforce