title: When comorbidity, aging, and complexity of primary care meet: development and validation of the Geriatric CompleXity of Care Index.
abstract: OBJECTIVE
  To develop and validate the Geriatric CompleXity of Care Index (GXI), a comorbidity index of medical, geriatric, and psychosocial conditions that addresses disease severity and intensity of ambulatory care for older adults with chronic conditions.
  
  
  METHODS
  DEVELOPMENT phase: variable selection and rating by clinician panel. VALIDATION phase: medical record review and secondary data analysis.
  
  
  METHODS
  Assessing the Care of Vulnerable Elders-2 study.
  
  
  METHODS
  Six hundred forty-four older (≥75) individuals receiving ambulatory care.
  
  
  METHODS
  
  
  
  METHODS
  32 conditions categorized according to severity, resulting in 117 GXI variables. A panel of clinicians rated each GXI variable with respect to the added difficulty of providing primary care for an individual with that condition.
  
  
  RESULTS
  Modified versions of previously validated comorbidity measures (simple count, Charlson, Medicare Hierarchical Condition Category), longitudinal clinical outcomes (functional decline, survival), intensity of ambulatory care (primary, specialty care visits, polypharmacy, number of eligible quality indicators (NQI)) over 1 year of care.
  
  
  RESULTS
  The most-morbid individuals (according to quintiles of GXI) had more visits (7.0 vs 3.7 primary care, 6.2 vs 2.4 specialist), polypharmacy (14.3% vs 0% had ≥14 medications), and greater NQI (33 vs 25) than the least-morbid individuals. Of the four comorbidity measures, the GXI was the strongest predictor of primary care visits, polypharmacy, and NQI (P < .001, controlling for age, sex, function-based vulnerability).
  
  
  CONCLUSIONS
  Older adults with complex care needs, as measured by the GXI, have healthcare needs above what previously employed comorbidity measures captured. Healthcare systems could use the GXI to identify the most complex elderly adults and appropriately reimburse primary providers caring for older adults with the most complex care needs for providing additional visits and coordination of care.
authors.affiliation: Division of Geriatrics, Department of Medicine, School of Medicine, University of Michigan, Ann Arbor, MI 48109, USA. lmin@med.umich.edu
authors.forename: Lillian
authors.initials: L
authors.lastname: Min
authors.forename: Neil
authors.initials: N
authors.lastname: Wenger
authors.forename: Anne M
authors.initials: AM
authors.lastname: Walling
authors.forename: Caroline
authors.initials: C
authors.lastname: Blaum
authors.forename: Christine
authors.initials: C
authors.lastname: Cigolle
authors.forename: David A
authors.initials: DA
authors.lastname: Ganz
authors.forename: David
authors.initials: D
authors.lastname: Reuben
authors.forename: Paul
authors.initials: P
authors.lastname: Shekelle
authors.forename: Carol
authors.initials: C
authors.lastname: Roth
authors.forename: Eve A
authors.initials: EA
authors.lastname: Kerr
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002908:Chronic Disease / Q000453:epidemiology / Q000628:therapy*; D015897:Comorbidity; D005260:Female; D015577:Geriatric Assessment / Q000706:statistics & numerical data*; D006302:Health Services Research; D006299:Health Services for the Aged / Q000458:organization & administration; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D011320:Primary Health Care / Q000458:organization & administration*; D011785:Quality Assurance, Health Care / Q000592:standards*; D012720:Severity of Illness Index