title: Nurse staffing and mortality for Medicare patients with acute myocardial infarction.
abstract: BACKGROUND
  Recent hospital reductions in registered nurses (RNs) for hospital care raise concerns about patient outcomes.
  
  
  OBJECTIVE
  Assess the association of nurse staffing with in-hospital mortality for patients with acute myocardial infarction (AMI).
  
  
  METHODS
  Medical record review data from the 1994-1995 Cooperative Cardiovascular Project were linked with American Hospital Association data for 118,940 fee-for-service Medicare patients hospitalized with AMI. Staffing levels were represented as nurse to patient ratios categorized into quartiles for RNs and for licensed practical nurses (LPNs).
  
  
  METHODS
  In-hospital mortality.
  
  
  RESULTS
  From highest to lowest quartile of RN staffing, in-hospital mortality was 17.8%, 17.4%, 18.5%, and 20.1%, respectively (P < 0.001 for trend). However, from highest to lowest quartile of LPN staffing, mortality was 20.1%, 18.7%, 17.9%, and 17.2%, respectively P < 0.001). After adjustment for patient demographic and clinical characteristics, treatment, and for hospital volume, technology index, and teaching and urban status, patients treated in environments with higher RN staffing were less likely to die in-hospital; odds ratios (95% confidence intervals) of quartiles 4, 3, and 2 versus quartile 1 were 0.91 (0.86-0.97), 0.94 (0.88-1.00), and 0.96 (0.90-1.02), respectively. Conversely, after adjustment, patients treated in environments with higher LPN staffing were more likely to die in-hospital; odds ratios (95% confidence intervals) of quartiles 4, 3, and 2 versus quartile 1 were 1.07 (1.00-1.15), 1.02 (0.96-1.09), and 1.00 (0.94-1.07), respectively.
  
  
  CONCLUSIONS
  Even after extensive adjustment, higher RN staffing levels were associated with lower mortality. Our findings suggest an important effect of nurse staffing on in-hospital mortality.
authors.affiliation: Division of Preventive Medicine, Center for Outcomes and Effectiveness Research and Education, Birmingham, Alabama, USA. sperson@uab.edu
authors.forename: Sharina D
authors.initials: SD
authors.lastname: Person
authors.forename: Jeroan J
authors.initials: JJ
authors.lastname: Allison
authors.forename: Catarina I
authors.initials: CI
authors.lastname: Kiefe
authors.forename: Michael T
authors.initials: MT
authors.lastname: Weaver
authors.forename: O Dale
authors.initials: OD
authors.lastname: Williams
authors.forename: Robert M
authors.initials: RM
authors.lastname: Centor
authors.forename: Norman W
authors.initials: NW
authors.lastname: Weissman
mesh_terms: D000368:Aged; D004506:Education, Nursing / Q000706:statistics & numerical data; D018588:Fee-for-Service Plans; D005260:Female; D006302:Health Services Research; D017052:Hospital Mortality; D006784:Hospitals, Teaching / Q000592:standards / Q000706:statistics & numerical data; D006786:Hospitals, Urban / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D006278:Medicare / Q000706:statistics & numerical data*; D009203:Myocardial Infarction / Q000401:mortality* / Q000451:nursing*; D009741:Nursing Staff, Hospital / Q000592:standards / Q000600:supply & distribution*; D009743:Nursing, Practical / Q000592:standards; D017063:Outcome Assessment, Health Care; D010561:Personnel Staffing and Scheduling / Q000145:classification / Q000592:standards*; D014481:United States / Q000453:epidemiology; D000078329:Workforce