Water-loss (intracellular) dehydration assessed using urinary tests, how well do they work? Diagnostic accuracy in older people

Hooper, Lee, Bunn, Diane K, Abdelhamid, Asmaa, Gillings, Rachel, Jennings, Amy, Maas, Katie, Millar, Sophie, Twomlow, Elizabeth, Hunter, Paul R, Shepstone, Lee, Potter, John F and Fairweather-Tait, Susan J (2016) Water-loss (intracellular) dehydration assessed using urinary tests, how well do they work? Diagnostic accuracy in older people. American Journal of Clinical Nutrition, 104 (1). pp. 121-131. ISSN 0002-9165

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Abstract

Background: Water-loss dehydration (hypertonic, hyperosmotic or intra-cellular dehydration) is due to insufficient fluid intake and distinct from hypovolemia due to excess fluid losses. It is associated with poor health outcomes such as disability and mortality in older people. Urine specific gravity (USG), color and urine osmolality have been widely advocated for screening for dehydration in older adults. Objective: To assess the diagnostic accuracy of urinary measures to screen for water-loss dehydration in older people.Design: This was a diagnostic accuracy study of people aged ≥65years taking part in the Dehydration Recognition In our Elders (DRIE, living in long-term care) or Dietary Strategies for Healthy Ageing in Europe (NU-AGE, living in the community) studies. The reference standard was serum osmolality, index tests included USG, urine color, osmolality, cloudiness, additional dipstick measures, ability to provide a urine sample, and volume of a random urine sample. Minimum useful diagnostic accuracy was set at sensitivity and specificity ≥70% or receiver operating characteristics plot area under the curve ≥0.70. Results: DRIE participants (67% women, mean age 86 years, n=162) had more limited cognitive and functional abilities than NU-AGE participants (64% women, mean age 70 years, n=151). 19% of DRIE and 22% of NU-AGE participants were dehydrated (serum osmolality >300mOsm/kg). Neither USG nor any other potential urinary tests were usefully diagnostic for water-loss dehydration. Conclusions: Although USG, urine color and urinary osmolality have been widely advocated for screening for dehydration in older adults, we show in the largest study to date that their diagnostic accuracy is too low to be useful and these measures should not be used to indicate hydration status in older people (either alone or as part of a wider tranche of tests). There is a need to develop simple, inexpensive and non-invasive tools for the assessment of dehydration in older people.

Item Type: Article
Additional Information: This is a free access article, distributed under terms (http://www.nutrition.org/publications/guidelines-and-policies/license/) that permit unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Uncontrolled Keywords: sensitivity and specificity,dehydration,aged,osmolar concentration,specific gravity,urinalysis
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Pure Connector
Date Deposited: 13 Apr 2016 08:40
Last Modified: 14 Sep 2020 23:38
URI: https://ueaeprints.uea.ac.uk/id/eprint/58182
DOI: 10.3945/ajcn.115.119925

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