title: Multimorbidity and healthcare utilisation among high-cost patients in the US Veterans Affairs Health Care System.
abstract: OBJECTIVE
  To investigate the relationship between multimorbidity and healthcare utilisation patterns among the highest cost patients in a large, integrated healthcare system.
  
  
  METHODS
  In this retrospective cross-sectional study of all patients in the U.S. Veterans Affairs (VA) Health Care System, we aggregated costs of individuals' outpatient and inpatient care, pharmacy services and VA-sponsored contract care received in 2010. We assessed chronic condition prevalence, multimorbidity as measured by comorbidity count, and multisystem multimorbidity (number of body systems affected by chronic conditions) among the 5% highest cost patients. Using multivariate regression, we examined the association between multimorbidity and healthcare utilisation and costs, adjusting for age, sex, race/ethnicity, marital status, homelessness and health insurance status.
  
  
  METHODS
  USA VA Health Care System.
  
  
  METHODS
  5.2 million VA patients.
  
  
  METHODS
  Annual total costs; absolute and share of costs generated through outpatient, inpatient, pharmacy and VA-sponsored contract care; number of visits to primary, specialty and mental healthcare; number of emergency department visits and hospitalisations.
  
  
  RESULTS
  The 5% highest cost patients (n=261,699) accounted for 47% of total VA costs. Approximately two-thirds of these patients had chronic conditions affecting ≥3 body systems. Patients with cancer and schizophrenia were less likely to have documented comorbid conditions than other high-cost patients. Multimorbidity was generally associated with greater outpatient and inpatient utilisation. However, increased multisystem multimorbidity was associated with a higher outpatient share of total costs (1.6 percentage points per affected body system, p<0.01) but a lower inpatient share of total costs (-0.6 percentage points per affected body system, p<0.01).
  
  
  CONCLUSIONS
  Multisystem multimorbidity is common among high-cost VA patients. While some patients might benefit from disease-specific programmes, for most patients with multimorbidity there is a need for interventions that coordinate and maximise efficiency of outpatient services across multiple conditions.
authors.affiliation: Center for Innovation to Implementation, VA Palo Alto Health Care System, Menlo Park, California, USA Division of General Medical Disciplines, Stanford University, Stanford, California, USA.
authors.forename: Donna M
authors.initials: DM
authors.lastname: Zulman
authors.affiliation: Center for Innovation to Implementation, VA Palo Alto Health Care System, Menlo Park, California, USA Health Economics Resource Center, VA Palo Alto Health Care System, Menlo Park, California, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Pal Chee
authors.affiliation: Center for Innovation to Implementation, VA Palo Alto Health Care System, Menlo Park, California, USA Health Economics Resource Center, VA Palo Alto Health Care System, Menlo Park, California, USA Health Research and Policy, Stanford University, Stanford, California, USA.
authors.forename: Todd H
authors.initials: TH
authors.lastname: Wagner
authors.affiliation: Center for Innovation to Implementation, VA Palo Alto Health Care System, Menlo Park, California, USA Health Economics Resource Center, VA Palo Alto Health Care System, Menlo Park, California, USA.
authors.forename: Jean
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Division of General Medical Disciplines, Stanford University, Stanford, California, USA.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Cohen
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California, USA.
authors.forename: Tyson H
authors.initials: TH
authors.lastname: Holmes
authors.affiliation: Division of Geriatrics, University of California, San Francisco, California, USA San Francisco VA Medical Center, San Francisco, California, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Ritchie
authors.affiliation: Center for Innovation to Implementation, VA Palo Alto Health Care System, Menlo Park, California, USA Division of General Medical Disciplines, Stanford University, Stanford, California, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Asch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease / Q000191:economics* / Q000453:epidemiology / Q000628:therapy; D015897:Comorbidity; D003430:Cross-Sectional Studies; D019033:Delivery of Health Care, Integrated / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006787:Hospitals, Veterans / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D015995:Prevalence; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D014493:United States Department of Veterans Affairs / Q000191:economics; D058014:Veterans Health / Q000191:economics* / Q000706:statistics & numerical data
keywords: GERIATRIC MEDICINE; HEALTH SERVICES ADMINISTRATION & MANAGEMENT; PRIMARY CARE