title: The effects of dehydration on rehabilitation outcomes of elderly orthopedic patients.
abstract: OBJECTIVE
  To study the effects of dehydration, by using the indices of prerenal azotemia and orthostasis, on the rehabilitation outcomes of elderly orthopedic patients.
  
  
  METHODS
  Prospective, pilot study.
  
  
  METHODS
  Regional inpatient rehabilitation center.
  
  
  METHODS
  A consecutive sample of 39 patients (29 women, 10 men), ranging in age from 58 to 94 years (mean, 78y), of whom 13 had total hip replacements, 12 had total knee replacements, and 14 had hip fractures.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Length of stay (LOS), change in the FIM trade mark instrument score, and discharge to home.
  
  
  RESULTS
  The mean LOS was significantly longer in the group with prerenal azotemia (n=21, 12.9+/-3.0d, t=2.49, P<.01) than in the nonazotemic group (n=18, 9.4+/-4.6d). LOS was also significantly longer in the orthostatic group (n=18, 13.7+/-3.4d, t=2.94, P<.01) than in the nonorthostatic group (n=21, 9.8+/-3.9d). Two-way analysis of variance showed a statistically significant effect on LOS for both azotemia (F=8.4, P=.006) and orthostasis (F=10.5, P=.003). A statistical interaction existed (F=4.7, P=.038), but it was more pronounced in the absence of both conditions, as opposed to the presence of both. LOS for the group with both azotemia and orthostasis was 13.6+/-2.7 days (n=10, F=4.7, P=.038), in contrast to 7.2+/-2.8 days in the group without either condition (n=10). Of the patients who had neither azotemia nor orthostasis, 100% (n=10) went home; 80% (n=8) of patients who had both conditions went home. Logistic regression analysis, however, did not show a statistically significant correlation between discharge to home and the presence of azotemia, orthostasis, or both.
  
  
  CONCLUSIONS
  Prerenal azotemia and orthostasis are present in a significant number of elderly orthopedic patients and have a major effect on rehabilitation outcomes.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Boston University, MA, USA. JMUKAND@saintjosephri.com
authors.forename: Jon A
authors.initials: JA
authors.lastname: Mukand
authors.forename: Chunbo
authors.initials: C
authors.lastname: Cai
authors.forename: Anita
authors.initials: A
authors.lastname: Zielinski
authors.forename: Michele
authors.initials: M
authors.lastname: Danish
authors.forename: Judith
authors.initials: J
authors.lastname: Berman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000534:rehabilitation; D019645:Arthroplasty, Replacement, Knee / Q000534:rehabilitation; D003681:Dehydration / Q000150:complications*; D005260:Female; D006305:Health Status Indicators; D006620:Hip Fractures / Q000534:rehabilitation / Q000601:surgery; D006801:Humans; D007024:Hypotension, Orthostatic / Q000150:complications; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000534:rehabilitation*; D010865:Pilot Projects; D011446:Prospective Studies; D016896:Treatment Outcome; D014511:Uremia / Q000150:complications