title: Co-morbidity adjustment for functional outcomes in community-dwelling older adults.
abstract: OBJECTIVE
  To characterize relationships between self-reported co-morbidity and functional outcomes in community-dwelling older adults, and to assess whether the impact of co-morbidity persists even after adjustment for baseline functional status.
  
  
  METHODS
  Prospective observational study. We examined associations between self-reported co-morbidity at baseline and functional outcomes at one year, with and without adjustment for baseline functional status.
  
  
  METHODS
  Outpatient clinics at a managed care and a Veterans Affairs site.
  
  
  METHODS
  Four hundred and fifty-seven community-dwelling older adults representing a broad spectrum of overall health status.
  
  
  METHODS
  (a) New basic ADL (activities of daily living) problem during follow-up; (b) 10-point decline in the physical function index of the MOS-36 (MOS-PFI).
  
  
  RESULTS
  Co-morbidity was associated with adverse functional outcomes in bivariable analyses. After adjustment for age and baseline functional status, an accumulated co-morbidity score provided additional explanatory power for predicting new ADL problems; odds ratios were 2.30 (1.09, 5.09) and 2.96 (1.48, 6.25) for 2 and > or = 3 affected co-morbidity domains, respectively. The impact of baseline status was also important; odds ratios for new ADL problems were 4.77 (2.68, 8.81) when at least one instrumental activity of daily living (IADL) problem was present at baseline, and 15.6 (8.05, 31.3) when at least one basic ADL problem was present at baseline.
  
  
  CONCLUSIONS
  Accumulated self-reported co-morbidity has significant negative effects on function at one year; these effects are attenuated but not eliminated by adjustment for baseline status. Co-morbidity adjustment is probably an important design element in clinical research focused on functional outcomes in older adults.
authors.affiliation: Department of Internal Medicine and Center on Aging, University of Kansas School of Medicine, Kansas City 66160-7376, USA. srigler@kumc.edu
authors.forename: Sally K
authors.initials: SK
authors.lastname: Rigler
authors.forename: Stephanie
authors.initials: S
authors.lastname: Studenski
authors.forename: Dennis
authors.initials: D
authors.lastname: Wallace
authors.forename: Dean M
authors.initials: DM
authors.lastname: Reker
authors.forename: Pamela W
authors.initials: PW
authors.lastname: Duncan
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012111:Residence Characteristics