title: Intensive Care Unit Admission and Survival among Older Patients with Chronic Obstructive Pulmonary Disease, Heart Failure, or Myocardial Infarction.
abstract: BACKGROUND
  Admission to an intensive care unit (ICU) may be beneficial to patients with pneumonia with uncertain ICU needs; however, evidence regarding the association between ICU admission and mortality for other common conditions is largely unknown.
  
  
  OBJECTIVE
  To estimate the relationship between ICU admission and outcomes for hospitalized patients with exacerbation of chronic obstructive pulmonary disease (COPD), exacerbation of heart failure (HF), or acute myocardial infarction (AMI).
  
  
  METHODS
  We performed a retrospective cohort study of all acute care hospitalizations from 2010 to 2012 for U.S. fee-for-service Medicare beneficiaries aged 65 years and older admitted with COPD exacerbation, HF exacerbation, or AMI. We used multivariable adjustment and instrumental variable analysis to assess each condition separately. The instrumental variable analysis used differential distance to a high ICU use hospital (defined separately for each condition) as an instrument for ICU admission to examine marginal patients whose likelihood of ICU admission depended on the hospital to which they were admitted. The primary outcome was 30-day mortality. Secondary outcomes included hospital costs.
  
  
  RESULTS
  Among 1,555,798 Medicare beneficiaries with COPD exacerbation, HF exacerbation, or AMI, 486,272 (31%) were admitted to an ICU. The instrumental variable analysis found that ICU admission was not associated with significant differences in 30-day mortality for any condition. ICU admission was associated with significantly greater hospital costs for HF ($11,793 vs. $9,185, P < 0.001; absolute increase, $2,608 [95% confidence interval, $1,377-$3,840]) and AMI ($19,513 vs. $14,590, P < 0.001; absolute increase, $4,922 [95% confidence interval, $2,665-$7,180]), but not for COPD.
  
  
  CONCLUSIONS
  ICU admission did not confer a survival benefit for patients with uncertain ICU needs hospitalized with COPD exacerbation, HF exacerbation, or AMI. These findings suggest that the ICU may be overused for some patients with these conditions. Identifying patients most likely to benefit from ICU admission may improve health care efficiency while reducing costs.
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine.|2 Institute for Healthcare Policy and Innovation.|3 Michigan Center for Integrative Research in Critical Care, and.
authors.forename: Thomas S
authors.identifier: http://orcid.org/0000-0002-5766-4970
authors.initials: TS
authors.lastname: Valley
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine.|3 Michigan Center for Integrative Research in Critical Care, and.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Sjoding
authors.affiliation: 2 Institute for Healthcare Policy and Innovation.|4 Center for Health Outcomes and Policy, University of Michigan; and.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Ryan
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine.|2 Institute for Healthcare Policy and Innovation.|5 Veterans Affairs Center for Clinical Management Research, Ann Arbor, Michigan.
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Iwashyna
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine.|2 Institute for Healthcare Policy and Innovation.|3 Michigan Center for Integrative Research in Critical Care, and.|4 Center for Health Outcomes and Policy, University of Michigan; and.
authors.forename: Colin R
authors.initials: CR
authors.lastname: Cooke
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D006333:Heart Failure / Q000401:mortality*; D017721:Hospital Costs / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D006278:Medicare / Q000191:economics; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000401:mortality*; D029424:Pulmonary Disease, Chronic Obstructive / Q000401:mortality*; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D014481:United States / Q000453:epidemiology
keywords: chronic obstructive pulmonary disease; heart failure; instrumental variable; intensive care; myocardial infarction