title: Hospital-acquired anemia: prevalence, outcomes, and healthcare implications.
abstract: BACKGROUND
  Evidence suggests that patients with normal hemoglobin (Hgb) levels on hospital admission who subsequently develop hospital-acquired anemia (HAA) may be at risk for adverse outcomes. Our objectives were to (1) determine the prevalence of HAA and (2) examine whether HAA is associated with increased mortality, length of stay (LOS), and total hospital charges.
  
  
  METHODS
  The population consisted of 417,301 adult hospitalizations from January 1, 2009 to August 31, 2011, in an academic medical center and 9 community hospitals. Patients with anemia on admission, and hospitals in the health system without available laboratory data were excluded; 188,447 hospitalizations were included in the analysis. Demographics, comorbidities, and outcomes were retrieved from administrative data; Hgb values were taken from the electronic medical record. Regression modeling was used to examine the association between demographics, comorbidity, hospitalization type, and HAA variables (mild: Hgb >11 and <12 g/dL for women, and >11 and <13 g/dL for men; moderate: Hgb 9.1 to ≤ 11.0 g/dL; severe: Hgb ≤ 9.0 g/dL) on mortality, LOS, and hospital charges.
  
  
  RESULTS
  Among 188,447 hospitalizations, 139,807 patients (74%) developed HAA: mild, 40,828 (29%); moderate, 57,184 (41%); and severe, 41,795 (30%). Risk-adjusted odds ratios and 95% confidence intervals for in-hospital mortality with HAA were: mild, 1.0 (0.88-1.17; P = 0.8); moderate, 1.51 (1.33-1.71, P < 0.001); and severe, 3.28 (2.90-3.72, P < 0.001). Risk-adjusted relative mean LOS and hospital charges relative to no HAA were higher with HAA: LOS: mild, 1.08 (1.08-1.10, P < 0.001); moderate, 1.28 (1.26-1.29, P < 0.001); severe, 1.88 (1.86-1.89, P < 0.001). Hospital charges: mild, 1.06 (1.06-1.07, P < 0.001); moderate, 1.18 (1.17-1.19, P < 0.001); severe, 1.80 (1.79-1.82, P < 0.001).
  
  
  CONCLUSIONS
  HAA is common and associated with increased mortality and resource utilization. Factors related to its development necessitate further study.
authors.affiliation: Department, of Cardiothoracic Anesthesia, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio; Quality and Patient Safety Institute, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Colleen G
authors.initials: CG
authors.lastname: Koch
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Sun
authors.forename: Eric D
authors.initials: ED
authors.lastname: Hixson
authors.forename: Anne
authors.initials: A
authors.lastname: Tang
authors.forename: Shannon C
authors.initials: SC
authors.lastname: Phillips
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Blackstone
authors.forename: J Michael
authors.initials: JM
authors.lastname: Henderson
mesh_terms: D000328:Adult; D000368:Aged; D000740:Anemia / Q000175:diagnosis* / Q000401:mortality*; D005260:Female; D017722:Hospital Charges / Q000639:trends*; D017052:Hospital Mortality / Q000639:trends*; D006760:Hospitalization / Q000639:trends; D006801:Humans; D007902:Length of Stay / Q000639:trends; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011787:Quality of Health Care / Q000639:trends*; D016896:Treatment Outcome