title: The impact of membership in a health maintenance organization on hospital admission rates for acute chest pain.
abstract: OBJECTIVE
  We evaluate the impact of membership in a staff-model health maintenance organization (HMO) on hospital admission rates for patients presenting to an emergency department with acute chest pain.
  
  
  METHODS
  Primary prospective data were gathered from all 3,006 patients presenting with a chief complaint of chest pain to the emergency department (ED) of a university teaching hospital from October 1987 to November 1989.
  
  
  METHODS
  Prospective cohort analysis used clinical data to stratify patients into groups at high (> or = 25%), medium (8-24%), and low risk (< or = 7%) of acute myocardial infarction (AMI). Insurance status was determined as either HMO, Medicare, commercial, Medicaid, or self-pay. Triage decisions were recorded, and patient outcomes of AMI and other final diagnoses were determined for all patients.
  
  
  METHODS
  Clinical data were recorded by the physicians in the ED as part of a detailed protocol. Insurance data were recorded separately by the ED staff as part of the hospital administrative database. Patient outcomes were recorded daily by research nurses for hospitalized patients; for patients who were discharged from the ED, telephone or physician follow-up was accomplished within seven days after discharge.
  
  
  RESULTS
  HMO patients were more likely to be admitted to the hospital than patients in other insurance groups in both the medium- and low-risk patient categories. Within the low-risk category, after controlling for clinical differences in a multiple logistic model, HMO membership retained an independent positive association with hospital admission compared to all other insurance groups except Medicaid.
  
  
  CONCLUSIONS
  For patients with acute chest pain who were at medium and low risk of acute myocardial infarction, HMO membership was associated with higher rates of hospital admission. These findings suggest that organizational factors beyond financial incentives may exercise an important influence on hospitalization rates for HMO patients.
authors.affiliation: Department of Ambulatory Care and Prevention, Harvard Community Health Plan, Boston, MA.
authors.forename: S D
authors.initials: SD
authors.lastname: Pearson
authors.forename: T H
authors.initials: TH
authors.lastname: Lee
authors.forename: E
authors.initials: E
authors.lastname: Lindsey
authors.forename: T
authors.initials: T
authors.lastname: Hawkins
authors.forename: E F
authors.initials: EF
authors.lastname: Cook
authors.forename: L
authors.initials: L
authors.lastname: Goldman
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001900:Boston; D002637:Chest Pain / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy*; D016001:Confidence Intervals; D003657:Decision Making; D004636:Emergency Service, Hospital; D005260:Female; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data*; D006302:Health Services Research; D006746:Hospital Bed Capacity, 500 and over; D006784:Hospitals, Teaching / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D007348:Insurance, Health / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000145:classification / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D010343:Patient Admission / Q000191:economics / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014218:Triage