Clinical signs of dehydration
in older people: a diagnostic
systematic review
Lee Hooper, Rowan A Needham,
John F Potter, Paul Hunter
(School of Medicine, University of East
Anglia & Gateshead NHS Trust)
[email protected]
Dehydration in older people…
Common – in UK Care homes 20-30%
dehydrated1
Associated with major causes of
mortality and morbidity in older
people2-4
Falls & fractures
Confusion & delirium
Heat stress, infections
Stroke, myocardial infarction
Poor wound healing, pressure ulcers
Drug toxicity (and more)
Dehydration in older people…
Associated
with risk of adverse
outcomes5
17% 30-day mortality in those admitted
with main diagnosis of dehydration
Expense
High levels of unplanned hospital
admissions (John Reid, Sec. State for
Health, 2004)6
1999 US hospital costs for 1° dehydration
~$1.1-1.4 billion/yr and rising fast7
To summarise:
Early
identification, prevention and
treatment of dehydration in the
community would be good for older
people and reduce NHS costs
Problem… identifying dehydration:
How
do GPs do it?
Clinical skills textbooks for
doctors:
Assess
skin turgor (Crawford,
Handbook of Signs and Symptoms8)
BUT “Unreliable in older people”
(need careful evaluation of dry oral
mucosa, dry axillae and reduced urine
output)
Problem… identifying dehydration:
How
do GPs do it?
Ask a junior doctor!
“In hospital blood tests are often relied
upon …
whilst these are still used in general
practice their usefulness is limited by the
time taken to get the results –
if someone is unwell enough to have
deranged blood results then they probably
need acute intervention and we shouldn’t
be delaying this waiting for results”
Problem… identifying dehydration:
How
do GPs do it in the community?
“we assess dehydration in the elderly most
often when there is an acute cause for
dehydration, such as diarrhoea or sepsis”.
Outside …hospital “we rely heavily on our
history and examination findings…. fluid
intake, quantity and colour of urine
passed…. dry mucus membranes…. rapid
pulse or prolonged capillary refill time”
Problem… identifying dehydration:
How
do GPs do it?
Signs
of advanced dehydration, when
action needs to be taken fast, include
“headache, dizziness and vasovagal
collapse ….
dropping blood pressure or postural
drop is a late and therefore worrying
sign”
Problem… identifying dehydration:
Every clinician and every book seem to give a
different set of clinical signs, including:
skin turgor, dry axillae
tongue dryness or furrows, dry oral mucosa
urine specific gravity,
urine volume and/or colour, fluid intake
sunken eyes,
upper-body weakness,
bio-electrical impedance,
checklists of risk factors,
rapid pulse, prolonged capillary refill time….
BUT - which are accurate? In the elderly?
Problem… identifying dehydration:
1. How to identify dehydration in community
& care homes early (blood tests rare)?
We need to clarify which clinical signs truly do
indicate early dehydration and late
dehydration older people
We also need to clarify what we mean by
dehydration – signs in people with blood loss
may be different from signs in people not
drinking enough, or losing fluid due to
diuretics, diarrhoea or fever
Problem… identifying dehydration:
We are systematically reviewing the
diagnostic accuracy of clinical and physical
signs vs. reference standards for
dehydration
The protocol is being registered with the
Cochrane Renal Group
Systematic review methods
How
do we define dehydration?
(Reference Standard)
experimentally induced dehydration
change in total body water, estimated
using deuterium oxide dilution
raised serum osmolality
a ≥3% drop in body weight over a week
or less, or the same increase in body
weight after rehydration
Systematic review methods
Included
studies will
compare an index test (clinical or
physical sign) with a reference standard
for impending and/or existing
dehydration, and
Be in people aged at least 65 years who
are hospitalised, living in the community,
or living in institutions, in a developed
country
Without diagnosed renal failure
Systematic review search
We have searched on Medline and EMBASE:
[older people] AND [hydration/osmolality
terms] AND [clinical and physical signs]
2040 possible titles and abstracts checked
Additional searches: 2913 Medline
142 papers collected as full text so far
We are just about to complete inclusion/
exclusion
Initial impressions: 10-15 relevant studies
Next steps
Working with a group of 7 medical students
(research project)
Complete inclusion/ exclusion of studies
Data extraction and assessment of validity
Analysis
Write up
Likely not to completely answer the
question BUT will provide a set of likely
biomarkers for a future cross-sectional
study
Earlier Systematic review
included studies published up to late 1997
few relevant studies (4)
limited evidence that in older people
dry axilla supported diagnosis of hypo-volaemia
(pos. likelihood ratio 2.8, 95% CI 1.4 to 5.4)
moist mucous membranes or tongue without
furrows supported lack of hypo-volaemia (neg
LR 0.3, 95% CI 0.1 to 0.6).
Capillary refill time and poor skin turgor were
not diagnostic9 (McGee 1999)
Earlier Systematic review
A
recent Australian cohort study in
older people found that
systolic blood pressure drop on standing,
sternal skin turgor,
tongue dryness and
body mass index
were
good indicators of early
dehydration on hospital admission10
BUT the standard was “subjective
clinically assessed dehydration”
References
1.
2.
3.
4.
5.
Kenkmann A et al. Health, wellbeing and nutritional
status of older people living in UK care homes. BMC
Geriatrics 2010, 10:28.
Thomas DR et al. Understanding clinical dehydration
& its treatment. J Am Med Dir Assoc 2008;9:292-301
Wakefield BJ et al. Risk factors & outcomes
associated with hospital admission for dehydration.
Rehab Nurs 2008;33:233-41.
Chan J et al. Water, other fluids, & fatal coronary
heart disease: Adventist Health Study. Am J Epi
2002;155:827-33.
Waikar SS et al. Mortality after hospitalization with
mild, moderate & severe hyponatremia. Am J Med
2009;122:857-65.
References
6. John Reid MP, Secretary of State for Health, 11th
March 2004: Managing new realities -integrating the
care landscape.
www.dh.gov.uk/en/News/Speeches/Speecheslist/DH
_4076406
7. Xiao H et al. Economic burden of dehydration among
hospitalized elderly patients. Am J Health Syst
Pharm 2004;61:2534-40.
8. Crawford MH. Handbook of Signs & Symptoms, 2nd
ed. Springhouse, London 2007
9. McGee S, Abernethy WB3, Simel DL. Is this patient
hypovolemic? JAMA 1999;281:1022-9
10. Vivanti A, Harvey K, Ash S, Battistutta D. Clinical
assessment of dehydration in older people admitted
to hospital: what are the strongest indicators?
Archives of Gerontology & Geriatrics
2008;47(3):340-55.