title: Complex comorbidity clusters in OEF/OIF veterans: the polytrauma clinical triad and beyond.
abstract: BACKGROUND
  A growing body of research on US Veterans from Afghanistan and Iraq [Operations Enduring and Iraqi Freedom, and Operation New Dawn (OEF/OIF)] has described the polytrauma clinical triad (PCT): traumatic brain injury (TBI), posttraumatic stress disorder (PTSD), and pain. Extant research has not explored comorbidity clusters in this population more broadly, particularly co-occurring chronic diseases.
  
  
  OBJECTIVE
  The aim of the study was to identify comorbidity clusters among diagnoses of deployment-specific (TBI, PTSD, pain) and chronic (eg, hypertension, diabetes) conditions, and to examine the association of these clusters with health care utilization and adverse outcomes.
  
  
  METHODS
  This was a retrospective cohort study.
  
  
  METHODS
  The cohort comprised OEF/OIF Veterans who received care in the Veterans Health Administration in fiscal years (FY) 2008-2010.
  
  
  METHODS
  We identified comorbidity using validated ICD-9-CM code-based algorithms and FY08-09 data, followed by which we applied latent class analysis to identify the most statistically distinct and clinically meaningful patterns of comorbidity. We examined the association of these clusters with process measures/outcomes using logistic regression to correlate medication use, acute health care utilization, and adverse outcomes in FY10.
  
  
  RESULTS
  In this cohort (N=191,797), we found 6 comorbidity clusters. Cluster 1: PCT+Chronic Disease (5%); Cluster 2: PCT (9%); Cluster 3: Mental Health+Substance Abuse (24%); Cluster 4: Sleep, Amputation, Chronic Disease (4%); Cluster 5: Pain, Moderate PTSD (6%); and Cluster 6: Relatively Healthy (53%). Subsequent health care utilization patterns and adverse events were consistent with disease patterns.
  
  
  CONCLUSIONS
  These comorbidity clusters extend beyond the PCT and may be used as a foundation to examine coordination/quality of care and outcomes for OEF/OIF Veterans with different patterns of comorbidity.
authors.affiliation: *South Texas Veterans Health Care System †Department of Epidemiology and Biostatistics, University of Texas Health Science Center San Antonio, San Antonio ‡Texas A&M Health Science Center, Bryan §Department of Medicine, Division of Clinical Epidemiology, University of Texas Health Science Center San Antonio, San Antonio ∥Center for Applied Health Research, jointly sponsored by Central Texas Veterans Health Care System, and Scott and White Healthcare System, Temple, TX ¶Center for Health Quality, Outcomes and Economic Research, Edith Nourse Rogers Memorial VA Hospital, Bedford, MA #Department of Medicine, Division of Hospital Medicine, University of Texas Health Science Center San Antonio, San Antonio, TX.
authors.forename: Mary Jo V
authors.initials: MJ
authors.lastname: Pugh
authors.forename: Erin P
authors.initials: EP
authors.lastname: Finley
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Copeland
authors.forename: Chen-Pin
authors.initials: CP
authors.lastname: Wang
authors.forename: Polly H
authors.initials: PH
authors.lastname: Noel
authors.forename: Megan E
authors.initials: ME
authors.lastname: Amuan
authors.forename: Helen M
authors.initials: HM
authors.lastname: Parsons
authors.forename: Margaret
authors.initials: M
authors.lastname: Wells
authors.forename: Barbara
authors.initials: B
authors.lastname: Elizondo
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Pugh
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D000465:Algorithms; D015897:Comorbidity; D005260:Female; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D009104:Multiple Trauma / Q000453:epidemiology*; D012189:Retrospective Studies; D014481:United States; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data