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Which frail older people are dehydrated?
The UK DRIE study
Lee Hooper, Norwich Medical School
Diane K Bunn, Norwich Medical School
Alice Downing, University of Canberra
Florence O Jimoh, Norwich Medical School
Joyce Groves, Public and Patient Involvement in Research (PPIRes)
Carol Free, PPIRes
Vicky Cowap, NorseCare
John F Potter, Norwich Medical School
Paul R Hunter, Norwich Medical School
Lee Shepstone, Norwich Medical School
Corresponding author: Lee Hooper, Reader in Research Synthesis, Nutrition &
Hydration, Norwich Medical School, University of East Anglia, Norwich Research Park,
Norwich, Norfolk NR4 7TJ, UK. [email protected], +44 1603 591268 (fax +44 1603
593752).
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Running headline: dehydration in frail older people
Dehydration in frail older people, DRIE, page 1
ABSTRACT
Background: Water-loss dehydration in older people is associated with increased mortality
and disability. We aimed to assess the prevalence of dehydration in older people living in
UK long-term care, and associated cognitive, functional and health characteristics.
Methods: The Dehydration Recognition In our Elders (DRIE) cohort study included people
≥65 years living in long-term care without heart or renal failure. In a cross-sectional
baseline analysis we assessed serum osmolality, previously suggested dehydration risk
factors, general health, markers of continence, cognitive and functional health, nutrition
status and medications. Univariate linear regression was used to assess relationships
between participant characteristics and serum osmolality, then associated characteristics
entered into stepwise backwards multivariate linear regression.
Results: DRIE included 188 residents (mean age 86 years, 66% women) of whom 20%
were dehydrated (serum osmolality >300mOsm/kg). Linear and logistic regression
suggested that renal, cognitive and diabetic status were consistently associated with serum
osmolality and odds of dehydration, while potassium-sparing diuretics, sex, number of
recent health contacts, and bladder incontinence were sometimes associated. Thirst was
not associated with hydration status.
Conclusions: DRIE found high prevalence of dehydration in older people living in UK longterm care, reinforcing the proposed association between cognitive and renal function and
hydration. Dehydration is associated with increased mortality and disability in older people,
but trials to assess effects of interventions to support healthy fluid intakes in older people
living in residential care are needed to enable us to formally assess causal direction and
any health benefits of increasing fluid intakes.
Dehydration in frail older people, DRIE, page 2
Background
Water-loss dehydration results from insufficient fluid intake, is indicated by elevation of
directly measured serum osmolality, and undermines the health of older people. Consistent
evidence from appropriately adjusted prospective studies suggests dehydration is
associated with increased mortality in stroke patients and older people with and without
diabetes, and doubled 4-year disability risk (1-4).
Water is crucial to every bodily action, and maintenance of hydration is essential to life.
Membrane osmoreceptors monitor water-balance (5;6). In healthy young humans restricted
fluid intake leads to raised serum osmolality, triggering thirst leading to increased fluid
intake, and releasing vasopressin (anti-diuretic hormone) which reduces fluid loss via the
kidneys, increasing urine concentration. This restores water balance. Older people are
thought to be at greater risk of dehydration as thirst sensation and urinary concentrating
ability frequently decline with age (7-9). Many older people use diuretics or laxatives which
encourage fluid loss, and reduced muscle volume leads to a smaller fluid reserve (10;11).
Oral fluid intake may fall in older people for a variety of reasons (12;13), including reduced
enjoyment of drinks, physical limitations, unmet activities of daily living needs and decisions
aimed at controlling continence (6;14;15). Additionally, those with dementia may forget to
drink as daily routines are lost and social contact diminishes. This suggests that cognitive
impairment, poor thirst and poor renal function are likely to increase dehydration risk, but
there is little direct evidence of this.
Hydration status needs to be assessed in older people using serum or plasma osmolality,
the core physiological indicator of dehydration, as other measures become less useful and
specific with increasing age (16-18). Creatinine-based measures are unhelpful in people
Dehydration in frail older people, DRIE, page 3
with limited renal function and are non-specific (also responding to cardiac failure,
sarcopenia etc.) (17;19). Weight change (a crucial measure of dehydration in children,
infants, and athletes) can be misleading as dehydration may occur slowly in older people,
not triggering rapid weight change thresholds (20), while weight can fluctuate in wellhydrated older adults (21). Signs and tests for dehydration, such as skin turgor, dry mouth,
capillary refill time and urinary measures appear to be poor indicators of dehydration or at
best lack any evidence-base in older adults (22). Although clinicians and researchers rarely
routinely measure serum osmolality directly (using freezing point depression) they indirectly
recognise its import by estimating it using a variety of osmolarity equations (23;24).
To protect older people living in long-term (residential) care from dehydration and its
consequences, and to trial interventions to prevent dehydration, we need to understand its
prevalence and which individuals are most at risk. There is limited and contradictory
evidence of factors associated with dehydration in frail older adults (25). Studies that
assessed associations with dehydration or low fluid intake using more reliable indicators
(serum osmolality, tonicity, ICD codes or fluid intake over ≥24hours) in older people
identified greater age, female sex, and non-Caucasian ethnicity as associated with greater
risk in community-dwelling and hospitalised older people (26-30), though sex and age were
not related to hydration status in a large case-control study of hospital admissions (31). In
18 hospital-based patients dementia was associated with dehydration (32), and poor
cognition with low fluid intake in 57 long-term geriatric ward residents (33). Functional
limitations were associated with increased dehydration risk and low fluid intake in
community-dwelling older adults (26), and residents of geriatric units (33), but functional
limitations, needing help with drinking, speech impairment and drooling were associated
with improved fluid intake in 99 care-home residents (29). Health factors, including diuretic
Dehydration in frail older people, DRIE, page 4
use (31), obesity, diabetes, hypertension, and chronic disease have been associated with
dehydration (26), while urinary incontinence, reduced nutrient intake and fewer drinking
sessions have been associated with low fluid intake (29). As limited sets of factors
potentially associated with dehydration have been assessed in individual studies, often with
very few participants and without appropriate adjustment for confounding, we aimed to
assess a wide range of cognitive, functional and health-based potential risk factors for
dehydration (assessed by serum osmolality) in older people living in long-term care.
Dehydration in frail older people, DRIE, page 5
Methods
Dehydration Recognition In our Elders (DRIE) study methods are fully described in
Supplemental File A and summarised here, the protocol and published study paperwork
(23). DRIE was approved by the UK National Research Ethics Service Committee London–
East Research Ethics committee (11/LO/1997; 25 January 2012), and all study procedures
were in accordance with the ethical standards of the Helsinki Declaration.
DRIE included people aged ≥65 years living in long-term care (residential, nursing and
specialist-dementia homes) with written informed consent or written consultee agreement in
England. Where residents were unable to demonstrate capacity to provide informed
consent, but expressed desire to participate, we asked their consultee (people who knew
the potential participant well, usually a spouse, son, daughter or long-term friend) to tell us
whether the resident would have participated in our study if they still had capacity, and if so
to give their written agreement. The consultee completed an opinion form on behalf of the
resident, and we only included participants who had signed their own written informed
consent, or where we obtained signed consultee agreement. Residents could withdraw
consent, without providing reasons, at any point – verbally or through their behaviour (by
appearing not to want to converse or to take part in the interview).
We aimed for a representative sample of care-home residents, while recognising we were
likely to include higher proportions of those more physically and cognitively able. If residents
were eligible (not receiving palliative care and the care-home had no record of any
diagnosis of renal or cardiac failure ), had not told care staff they did not want to participate,
and carers felt the resident was well enough, we asked whether they might like to take part.
Dehydration in frail older people, DRIE, page 6
Where interested we discussed the participant information sheet, assessed capacity and
took consent or requested consultee advice.
Data were collected from care notes, staff and resident interviews. Non-fasting venous
blood was collected using needle and syringe, transferred to collection tubes and delivered
to the Department of Laboratory Medicine, Norfolk and Norwich University Hospitals Trust
within 4 hours. Serum osmolality (freezing point depression; Advance Instruments Model
2020, repeatability ±3 [SD ±1] mmol/kg in the 0–400mmol region, CV0.56), serum urea,
creatinine, sodium, potassium, glucose (Abbott Architect), and haemoglobin (Instrument
Sysmex XN) were measured in all available samples. Estimated glomerular filtration rate
(eGFR) was calculated (34). Hydration status was classified by serum osmolality: normally
hydrated (275 to <295mOsm/kg), impending dehydration (295–300mOsm/kg), current
dehydration (>300mOsm/kg) (17;19).
Interview questions included EuroQoL-5D-3L (www.euroqol.org/), Mini-Mental State
Examination (MMSE (35)), short questions on feelings, drinks, sleep, continence, and
exercise. Participants were asked whether they currently felt thirsty, just before
venepuncture. We physically assessed participant’s mouths, body temperature, hands,
feet, axilla and eyes. Weight, vision (Snellen test), blood pressure and pulse after sitting for
≥10 minutes (Omron M3), and after one and three minutes of standing were measured.
Care staff provided information on recent, current and chronic illnesses, health care
contacts, medications, weight history, functional status (Barthel Index), risk factors for poor
food and fluid intake or increased fluid requirements.
Dehydration in frail older people, DRIE, page 7
Data analysis: The DRIE population was described by hydration status. We assessed
participants’ representativeness compared to all care-home residents (living in homes
included in DRIE) by age, gender and body mass index (BMI). Univariate linear regression
(STATA 11) was used to assess relationships between participant characteristics (age, sex,
suggested dehydration risks, general health, markers of continence, cognitive and
functional health, nutrition status and medications used), 67 factors in all, and serum
osmolality. As a sensitivity analysis, to assess the stability of findings to different statistical
methods, we also used univariate logistic regression (STATA 11) to assess relationships
between these characteristics and odds of impending and current dehydration. Where
several characteristics within a category (categories shown in Supplemental Table 1) were
statistically significant to p<0.10 all were entered into multivariate linear regression and the
characteristic with the largest p-value removed stepwise until all remaining factors were
p<0.10 (this p-value was chosen to ensure that in this limited dataset we did not lose
potentially important factors too soon from the analyses). All remaining characteristics,
from all categories, were entered into the full backwards multifactorial regression model,
and the characteristic with the largest p-value removed each time until all remaining factors
were p<0.05. The same process was followed for multivariate logistic regression for both
impending and current dehydration.
There are two groups of people with raised serum osmolality, those with or without raised
serum glucose. For those without raised glucose fluid intake is increased to correct raised
osmolality, but for those with raised glucose (>7.8mmol/L or >140mg/dl) treatment is
primarily through diabetic control. We assessed whether risk factors for raised serum
osmolality and dehydration altered when we omitted participants with raised serum glucose.
Dehydration in frail older people, DRIE, page 8
The strong correlation between poorer cognitive function and osmolality encouraged us to
consider (post-hoc) whether lack of thirst may be a mediator. We hypothesised that in the
absence of thirst it is easier to forget to drink, so explored the relationship between feeling
thirsty (participants were asked whether they currently felt thirsty, just before venepuncture)
and osmolality, assessed using univariate linear regression.
Dehydration in frail older people, DRIE, page 9
Results
Interviews took place in 56 care-homes from April 2012 to August 2013. Homes included
1816 residents of whom 1077 were deemed ineligible by care-home managers (Figure 1).
Of the 739 potentially eligible residents approached by researchers, 374 were not
interested and 365 wanted to take part, of whom 256 provided informed consent or
consultee agreement. We initiated research interviews with 232 individuals, and obtained
serum osmolality for 201. Laboratory errors led to rejection of three serum osmolality
readings, seven participants had low osmolality and three cardiac failure (unknown before
interview), leaving 188 included participants.
Participant characteristics
The mean age of DRIE participants was 86 years (range 65 to 105), and 66% were women
(Table 1, where characteristics are also displayed by hydration status). Mean serum
osmolality was 293mOsm/kg and 52% were well hydrated, 28% had impending dehydration
and 20% current dehydration (Figure 2). Mean MMSE score was 22 (of 30, range 0 to 30)
and 22% had normal cognition (MMSE >26), 45% mild cognitive impairment (MMSE 20-26),
26% moderate cognitive impairment (MMSE 10-<19), and 3% severe cognitive impairment
(MMSE<10). Mean functional status was 67 (Barthel Index, range 0 to 100), 19% had
diabetes, and 16% were underweight (BMI <20kg/m2). Renal function was limited in many
participants, with mean eGFR of 63ml/min/1.73 m2 (SD 18.6, range 18 to 90ml/min/1.73m2)
Representativeness of participants
We obtained anonymous data on all residents for 45 (80.4%) of the 56 homes, including
1425 (78.6%) of 1812 residents. 101 were aged <65 years or had missing age data so
were omitted. DRIE participants were similar in sex ratio but slightly younger than the
Dehydration in frail older people, DRIE, page 10
overall care-home population, with higher BMI and lower likelihood of being undernourished
(BMI <20kg/m2), see Supplemental Table 1.
Characteristics associated with serum osmolality and dehydration
Characteristics associated (to p<0.10) with serum osmolality in univariate linear regression
and/or current or impending dehydration in univariate logistic regression (Supplemental
Table 2) were very similar to those in the group excluding those with raised/uncertain serum
glucose (Supplemental Table 3). These factors associated with osmolality and dehydration
included sex, general health factors (eGFR, number of health contacts in past 2 months,
number of emergency admissions in past 2 months, diabetic status, from notes (checked
with medications list and serum glucose), swollen ankles (current), chronic obstructive
pulmonary disease and arthritis, any type), continence issues (including Barthel Index
scores for bowel and bladder continence), cognitive and mental health factors (including
MMSE score and MMSE2 or MMSE squared, MMSE drawing score, type of consent
provided and staff assessment of dementia level), and use of medications (including those
for diabetes, laxatives, loop diuretics and potassium-sparing diuretics).
Multivariate analyses
Factors associated with a significantly higher serum osmolality by multivariate linear
regression were lower eGFR (signifying worse renal function), lower MMSE (lower cognitive
status), diabetic medication use and not taking potassium-sparing diuretics (Table 2) giving
this regression equation:
Serum osmolality = 306.0 – (0.086*eGFR) – (0.37 *MMSE) + 6.72 if uses diabetic
medication – 4.93 if uses potassium-sparing diuretic.
Dehydration in frail older people, DRIE, page 11
The regression was also run using MMSE2 (as MMSE2 was more normally distributed than
MMSE), and the equation was similar (Serum osmolality = 302.8 – (0.085*eGFR) – (0.01
*MMSE2) + 6.60 if uses diabetic medication – 4.96 if uses potassium-sparing diuretics).
The pattern of poorer renal function, diabetic status, and poorer cognitive status being
associated with higher serum osmolality was largely mirrored in the multivariate logistic
regression where MMSE score or sub-score, eGFR, diabetic status or use of diabetic
medications, male sex and greater number of recent healthcare contacts were associated
with the odds of dehydration (Table 2).
Each ten point reduction in eGFR was associated with 20% higher odds of current and
impending dehydration, and each ten point MMSE fall with 70% higher odds of impending
dehydration. Not being able to draw two intersecting pentagons (part of the MMSE test),
was associated with 74% greater odds of current dehydration. Being diabetic was
associated with almost quadrupled odds of impending dehydration and use of diabetic
medication with seven-fold increase in odds of current dehydration. Men had doubled odds
of impending dehydration (compared to women) and every healthcare contact over the past
2 months was associated with 7% increase in odds of current dehydration.
For analyses omitting participants with raised glucose we removed 34 with serum glucose
>7.8mmol/L (>140mg/dl) and 26 without glucose data, leaving 128 people, of whom 22
(17%) had current dehydration and 33 (26%) impending dehydration (retaining nine
participants with diabetes and normal glucose). Univariate analyses are shown in
Supplemental Table 3. Multivariate regression (Supplemental Table 4) suggested factors
associated with serum osmolality were renal and cognitive function, use of diabetic
Dehydration in frail older people, DRIE, page 12
medication and potassium-sparing diuretics, and the regression equation was again similar
(Supplemental Table 4 footnote). The reduced analytic power in this smaller dataset was
clear in the dichotomised logistic regressions, where we struggled to retain statistically
significant associations, though eGFR and urinary incontinence were still associated with
impending dehydration, cognitive status and renal function current dehydration.
Fifty participants stated they felt thirsty before venepuncture. There was no relationship
between thirst and serum osmolality (p=0.998), see Figure 3, and a receiver operating
characteristic (ROC) plot of thirst and being dehydrated or not, gave and area under the
curve of 0.47, confirming thirst is not a good guide to the need to drink in older people.
Dehydration in frail older people, DRIE, page 13
Discussion
DRIE’s consistent findings (using various statistical models) suggest that cognitive status,
renal function and diabetic status are associated with dehydration in older people. For
older people in DRIE, thirst was a poor indicator of need to drink so that drinking must be
regulated instead by habit and routine, which are easily disrupted in those with dementia.
As renal function declines (45% of DRIE participants had eGFR <60ml/min/1.73 m2 and
18% eGFR <45ml/min/1.73m2) the ability of older people to conserve fluid declines. Those
with diabetes are more likely to experience raised serum glucose, raising serum osmolality,
but it is surprising that diabetic medication use is associated with dehydration risk when
participants with raised glucose are omitted.
While DRIE data support the theory of the causation of water-loss dehydration this was a
cross-sectional study. It is quite possible that water-loss dehydration causes poor renal
function and poor cognition, and the relationships could work in either or both directions.
The relationship between cognitive function and hydration status is potentially highly
complex as there is some (but mixed) evidence from children and young adults that
dehydration leads to reductions in cognitive performance and mood (42;43). If this is true
for older people then deficits in drinking due to cognitive frailty could lead to dehydration
which depresses cognition and thus drinking even further, a vicious circle. We all need to
preserve our cognitive function as we age - good hydration may support continued cognitive
agility, but more evidence is needed.
A weakness of DRIE was that participants were not totally representative of all care-home
residents. DRIE participants were similar in sex ratio but slightly younger than the overall
care-home population, and better nourished. Additionally, of residents who wanted to
participate, but lacked capacity give their own consent, we obtained signed consultee
Dehydration in frail older people, DRIE, page 14
agreement for <50%, compared to all who gave their own consent (Figure 1), so those with
cognitive impairment were relatively under-represented. As cognitive impairment is strongly
associated with dehydration, the true proportion of dehydrated care-home residents is
probably >20%.
Although the group of 188 DRIE participants is still a small sample, this is the first report to
our knowledge with a sample of older long-term care residents large enough to examine
associations between a good range of health and functional characteristics and serum
osmolality or hydration status, and to adjust well for confounding.
Serum osmolality, the reference standard for water-loss dehydration in older people, has
previously been measured in few, small groups of older people, so assessment of serum
osmolality in 188 UK care-home residents is a valuable addition to our understanding, and
a strength of DRIE as serum osmolality is the best measure of water-loss dehydration. We
found only two other care-home studies with serum osmolality measures, both from the US,
and with differing estimates of dehydration prevalence. Gaspar found that 8% of 36 longterm care residents had impending dehydration (0% current dehydration), while Stotts found
that 19% of 48 nursing home residents at risk for pressure ulcers had current dehydration
and a further 44% impending dehydration (36;37). There are also contradictory findings in
hospital settings. In older adults admitted to UK hospitals levels of dehydration varied from
4% to 58% (38-41) (Supplemental Table 5).
DRIE findings support those of previous small studies that dementia and diabetes are
associated with, and potentially risk factors for, dehydration (26;32;33). No previous studies
suggest associations with renal function or potassium-sparing diuretics. Our data do not
Dehydration in frail older people, DRIE, page 15
support that age, functional impairments, or nutritional status are associated with hydration
status in long-term care residents after adjustment for confounding, but recent healthcare
contacts and incontinence may be important associations, to be assessed in larger studies.
The limited size of this dataset mean that strong but rare predictors of dehydration (such as
requiring thickened drinks, a factor for only 8 of DRIE’s participants, see Supplemental
Table 2) did not retain high enough p-values to be seen in final models. In larger studies
we are likely to find additional strong indicators of dehydration.
Dehydration is associated with increased mortality and disability in older people, but high
quality trials to assess effects of interventions to support fluid intake in older people are
needed to enable us to formally assess the direction of causation, and the health effects of
increasing fluid intakes (44;45). Knowing which frail older people are most likely to be, or
become, dehydrated will enable future trials to be targeted to promising participants.
Dehydration in frail older people, DRIE, page 16
Conflict of interest: The authors declare no conflicts of interest, except that the European
Hydration Institute (EHI) supplied plane tickets and paid for 2 night’s hotel accommodation
for LH to give a talk on dehydration in older people at the EHI’s symposium at the
International Congress of Nutrition, Granada, Spain 16th-18th September 2013.
Funding: This paper summarises independent research funded by the National Institute of
Health Research Fellowship programme (grant number NIHR-CDF-2011-04-025, Career
Development Fellowship to LH). The views expressed are those of the authors and not
necessarily those of the NHS, the NIHR, the Department of Health or any other body. The
funders played no part in study design after funding was agreed, and no part in data
collection, analysis, interpretation, writing or deciding to submit for publication.
Acknowledgements: We would like to thank and acknowledge the participants of the DRIE
study, and DRIE advisory group members, for their help, time, enthusiasm, support, ideas
and participation with this work. We are also grateful to Sue Steel (UEA contracts manager
and DRIE study sponsor), Maddie Copley, Linda Gill and Hilary MacDonald (of AGE UK
Norfolk), and Fiona Poland (Professor of Social Research Methodology at UEA), for their
support and advice as part of the DRIE Steering Group.
Dehydration in frail older people, DRIE, page 17
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Dehydration in frail older people, DRIE, page 21
Table 1. Characteristics of DRIE study participants
Hydration status
Characteristic
All 188 DRIE
Current
Impending
Hydrated
participants
Dehydration
Dehydration
Mean (SD), n
Mean (SD), n
Mean (SD), n
Mean (SD), n
293.4 (8.1), 188
304.2 (3.5), 38
296.9 (1.6), 52
287.3 (5.5), 98
Sex, % Female
66% (124 of 188)
58% (22 of 38)
58% (30 of 52)
73% (72 of 98)
Age, years
85.7 (7.8), 188
84.6 (8.1), 38
85.3 (8.2), 52
86.2 (7.6), 98
MMSE Score (of 30)
21.8 (5.7), 180
19.3 (6.2), 34
21.6 (5.2), 48
22.6 (5.7), 96
Barthel Index (of 100)
67.4 (26.1), 188
61.4 (25.7), 38
69.0 (25.2), 52
68.8 (26.5), 98
Diabetes, %
19% (36 of 188))
37% (14 of 38)
23% (12 of 52)
10% (10 of 98)
Serum Glucose, mmol/L
7.0 (3.2), 164
9.3 (4.9), 33
6.9 (2.6), 44
6.2 (2.2), 87
eGFR, ml/min/1.73 m2
63.0 (18.6), 178
55.7 (19.6), 35
61.4 (18.9), 50
66.5 (17.3), 93
Medications, no. of
8.8 (4.5), 188
9.5 (3.5), 38
8.8 (5.1), 52
8.5 (4.5), 98
Diuretics, % prescribed
39% (73 of 188)
45% (17 of 38)
38% (20 of 52)
37% (36 of 98)
Drinks, self-reported
8.0 (2.7), 168
7.3 (3.0), 31
7.7 (2.8), 48
8.3 (2.3), 90
BMI, kg/m2
25.8 (5.6), 188
26.6 (5.9), 38
26.3 (6.3), 52
25.2 (5.1), 98
BMI <20, %
16% (30 of 188)
11% (4 of 38)
15% (8 of 52)
18% (18 of 98)
Weight, kg
69.0 (17.2), 188
76.0 (20.0), 38
69.2 (17.5), 52
66.1 (15.0), 98
Haemoglobin, g/dL
12.4 (1.5), 170
12.2 (1.0), 34
12.4 (1.8), 47
12.5 (1.4), 89
Serum Osmolality,
mOsm/kg
prescriptions
drinks/day
Dehydration in frail older people, DRIE, page 22
Table 2. Results of multivariate regressions for the full DRIE dataset (in 188 participants).
Type of
Linear regression on serum
Logistic regression on
Logistic regression on current
indicator
osmolality*
impending dehydration (90
dehydration (38 people have current
people have impending or
dehydration)
current dehydration)
Measure
Coefficient (95% CI),
Measure
p-value
Renal
eGFR
function
Cognitive
-0.09 (-0.15 to -0.03)
function
Measure
CI), p-value
eGFR
p=0.005
MMSE score
Odds ratio (95%
0.98 (0.96 to 0.99)
Odds ratio (95% CI),
p-value
eGFR
p=0.007
0.98 (0.95 to 1.00)
p=0.045
-0.37 (-0.56 to -0.18)
MMSE
0.93 (0.88 to 0.98)
MMSE drawing
0.26 (0.11 to 0.65)
p<0.001
score
p=0.010
sub-score
p=0.004
Diabetic
Uses diabetic
6.72 (3.39 to 10.04)
Diabetic
3.77 (1.59 to 8.93)
Use of any
6.77 (2.18 to 21.04)
status
medication
p<0.001
status
p=0.003
diabetic
p=0.001
medication
Other factors Potassiumsparing
diuretic
-4.93 (-9.09 to -0.77)
p=0.021
sex
2.00 (1.01 to 3.97)
Healthcare
1.07 (1.01 to 1.13)
p=0.047
contacts in past
p=0.027
2 months
*Serum osmolality = 306.0 – (0.086*eGFR) – (0.37 *MMSE) + 6.72 if uses diabetic medication – 4.93 if uses potassium-sparing
diuretics
Dehydration in frail older people, DRIE, page 23
Figure captions
Figure 1. Flow diagram for the Dehydration Recognition In our Elders (DRIE) study
Dehydration in frail older people, DRIE, page 24
Figure 2. Percentages of older people living in residential care with current dehydration
(20%, serum osmolality >300mOsm/kg), impending dehydration (28%, 295-300mOsm/kg),
and who were well hydrated (52%, 275-<295mOsm/kg) in the Dehydration Recognition In
our Elders (DRIE) study
Dehydration in frail older people, DRIE, page 25
Figure 3. Box plot of serum osmolality for those who expressed thirst, and those who said
they were not thirsty, just before venepuncture.
Dehydration in frail older people, DRIE, page 26
Online supplementary material:
Supplementary File A. DRIE Methodology
Ethics approval: DRIE was approved by the UK National Research Ethics Service
Committee London–East Research Ethics committee (11/LO/1997). Study procedures were
in accordance with the ethical standards of the Helsinki Declaration. DRIE included
participants who gave their own informed consent, and also some who were unable to give
informed consent (the process of inclusion of these participants was approved by our ethics
committee and is explained within this manuscript).
Contributions: the DRIE study was conceived by LH, and developed by LH, DKB, FJ, JG,
CF, VC, JP, PRH and LS. This analysis was conceived by LH, carried out by LH and AD
and developed by all authors. Data collection was carried out by LH, DKB and FJ. LH
wrote the first draft of the manuscript, all authors revised it critically for important intellectual
content and agreed the final draft. All authors declare themselves to be accountable for all
aspects of the work in ensuring that questions related to the accuracy or integrity of any part
of the work are appropriately investigated and resolved.
Study registration: DRIE was registered with the Research Register for Social Care,
www.researchregister.org.uk, 122273.
Indexing terms (MeSH headings): dehydration, aged, osmolar concentration, dementia,
diabetes mellitus, glomerular filtration rate, residential facilities, risk factors, long-term care
Dehydration in frail older people, DRIE, page 27