ueaeprints.uea.ac.uk · web viewthis paper summarises independent research funded by the national...

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).

Running headline: dehydration in frail older people

Dehydration in frail older people, DRIE, page 1

mailto:[email protected]

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 long-

term 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.


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


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 well-

hydrated 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


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.


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. 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.


http://www.euroqol.org/

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.


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.


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


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.


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


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.


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


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 long-

term 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 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.


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.


References

(1) Bhalla A, Sankaralingam S, Dundas R, Swaminathan R, Wolfe CD, Rudd AG, et al. Influence of raised plasma osmolality on clinical outcome after acute stroke. Stroke 2000 Sep;31(9):2043-8.

(2) Wachtel TJ, Tetu-Mouradjian LM, Goldman DL, Ellis SE, O'Sullivan PS. Hyperosmolarity and acidosis in diabetes mellitus: a three-year experience in Rhode Island. J Gen Intern Med 1991 Nov;6(6):495-502.

(3) Stookey JD, Purser JL, Pieper CF, Cohen HJ. Plasma hypertonicity: Another marker of frailty? J Am Geriatr Soc 2004;52(8):1313-20.

(4) Porock D, Oliver DP, Zweig S, Rantz M, Mehr D, Madsen R, et al. Predicting death in the nursing home: development and validation of the 6-month Minimum Data Set mortality risk index. J Gerontol A Biol Sci Med Sci 2005 Apr;60(4):491-8.

(5) Naitoh M, Burrell LM. Thirst in elderly subjects. In: Vellas B, Albarede JL, Garry PJ, editors. Hydration and aging.Paris: Serdi; 1998. p. 33-46.

(6) Hooper L, Bunn D, Jimoh FO, Fairweather-Tait SJ. Water-loss dehydration and aging. Mech Ageing Dev 2014;136-137:50-8.

(7) Davies I, O'Neill PA, McLean KA, Catania J, Bennett D. Age-associated Alterations in Thirst and Arginine Vasopressin in Response to a Water or Sodium Load. Age Ageing 1995;24(2):151-9.

(8) Lindeman RD, Tobin JN, Shock NW. Longitudinal studies on the rate of decline in renal function with age. J Am Geriatr Soc 1985;33(4):278-85.

(9) Morley JE. Water, water everywhere and not a drop to drink. J Gerontol A Biol Sci Med Sci 2000;55A(7):M359-M360.

(10) Olde Rikkert MGM, Deurenberg P, Jansen RWMM, van't Hof MA, Hoefnagels WHL. Validation of multi-frequency bioelectrical impedance analysis in detecting changes in fluid balance of geriatric patients. J Am Geriatr Soc 1997;45(11):1345-51.

(11) Martin AD, Daniel MZ, Drinkwater DT, Clarys JP. Adipose tissue density, estimated adipose lipid fraction and whole body adiposity in male cadavers. Int J Obes Relat Metab Disord 1994;18:79-83.

(12) Lindeman RD, Romero LJ, Liang HC, Baumgartner RN, Koehler KM, Garry PJ. Do elderly persons need to be encouraged to drink more fluids? J Gerontol A Biol Sci Med Sci 2000 Jul;55A(7):M361-M365.

(13) Zizza CA, Ellison KJ, Wernette CM, R. Total water intakes of community-living middle-old and oldest-old adults. J Gerontol A Biol Sci Med Sci 2009;64A(4):481-6.

(14) Appleton KM, Smith E. A role for identification in the gradual decline in the pleasantness of flavors with age. Journals of Gerontology Series B: Psychological Sciences and Social Sciences 2015;pii: gbv031. [Epub ahead of print]:1-7.


(15) He S, Craig BA, Xu H, Covinsky KE, Stallard E, Thomas J, et al. Unmet need for ADL asistance is associated with mortality among older adults with mild disability. J Gerontol A Biol Sci Med Sci 2015;70(9):1128-32.

(16) Cheuvront SN, Kenefick RW, Charkoudian N, Sawka MN. Physiologic basis for understanding quantitative dehydration assessment. Am J Clin Nutr 2013;97:455-62.

(17) Thomas DR, Cote TR, Lawhorne L, Levenson SA, Rubenstein LZ, Smith DA, et al. Understanding clinical dehydration and its treatment. JAMDA 2008;9(5):292-301.

(18) Institute of Medicine. Panel on Dietary Reference Intakes for Electrolytes and Water. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington DC, USA: National Academies Press; 2004.

(19) American Medical Directors Association (AMDA). Dehydration and fluid maintenance in the long-term care setting. Columbia (MD), USA: American Medical Directors Association (AMDA); 2009.

(20) Cheuvront SN, Ely BR, Kenefick RW, Sawka MN. Biological variation and diagnostic accuracy of dehydration assessment markers. Am J Clin Nutr 2010;92(3):565-73.

(21) Vivanti A, Yu L, Palmer M, Dakin L, Sun J, Campbell K. Short-term body weight fluctuations in older well-hydrated hospitalised patients. J Hum Nutr Diet 2013;26(5):429-35.

(22) Hooper L, Abdelhamid A, Atreed NJ, Campbell WW, Chassagne P, Channell AM, et al. Clinical symptoms, signs and tests for identification of impending and current water-loss dehydration in older people. Cochrane Database Syst Rev 2015;2015(4):CD009647.

(23) Siervo M, Bunn D, Prado C, Hooper L. Accuracy of prediction equations for serum osmolarity in frail older people with and without diabetes. Am J Clin Nutr 2014;100(3):867-76.

(24) Hooper L, Abdelhamid A, Ali A, Bunn D, Jennings A, John G, et al. Diagnostic accuracy of calculated serum osmolarity to predict dehydration in older people. submitted, June 2015.(25) Hooper L, Bunn DK. Detecting dehydration in older people: useful tests. Nurs Times 2015;111(32/33); 12-16.

(26) Stookey JD, Pieper CF, Cohen HJ. Is the prevalence of dehydration among community-dwelling older adults really low? Informing current debate over the fluid recommendation for adults aged 70+years. Public Health Nutr 2005;8(8):1275-85.

(27) Stookey JD. High prevalence of plasma hypertonicity among community-dwelling older adults: results from NHANES III. J Am Diet Assoc 2005 Aug;105(8):1231-9.

(28) Warren JL, Bacon WE, Harris T, McBean AM, Foley DJ, Phillips C, et al. The burden and outcomes associated with dehydration among US elderly, 1991. Am J Public Health 1994 Aug;84(8):1265-9.

(29) Gaspar P. Water intake of nursing home residents. J Gerontol Nurs 1999;25:22-9.


(30) Gaspar PM. What determines how much patients drink? Geriatr Nurs 1988;July/Aug:221-4.

(31) Lancaster KJ, Smiciklas-Wright H, Heller DA, Ahern FM, Jensen G. Dehydration in black and white older adults using diuretics. Ann Epidemiol 2003 Aug;13(7):525-9.

(32) Albert SG, Nakra BR, Grossberg GT, Caminal ER. Vasopressin response to dehydration in Alzheimer's disease. J Am Geriatr Soc 1989;37(9):843-7.

(33) Armstrong-Esther CA, Browne KD, Armstrong-Esther DC. The institutionalized elderly: dry to the bone! Int J Nurs Stud 1996;33(6):619-28.

(34) Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 1999;130(6):461-70.

(35) Folstein MF, Folstein SE, McHugh PR. "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research 1975;12(3):189-98.

(36) Gaspar PM. Comparison of four standards for determining adequate water intake of nursing home residents. Research and Theory for Nursing Practice 2011;25(1):11-22.

(37) Stotts NA, Hopf HW, Kayser-Jones J, Chertow GM, Cooper BA, Wu H-S. Increased fluid intake does not augment capacity to lay down new collagen in nursing home residents at risk for pressure ulcers: A randomized, controlled clinical trial. Wound Repair and Regeneration 2009;17(6):780-8.

(38) Walsh NP, Fortes MB, Raymond-Barker P, Bishop C, Owen J, Tye E, et al. Is whole-body hydration an important consideration in dry eye? Investigative Ophthalmology and Visual Science 2014;53(10):6622-7.

(39) Fletcher SJ, Slaymaker AE, Bodenham AR, Vucevic M, Fletcher SJ, Slaymaker AE, et al. Urine colour as an index of hydration in critically ill patients. Anaesthesia 1999 Feb;54(2):189-92.

(40) Kafri MW, Myint PK, Doherty D, Wilson AH, Potter JF, Hooper L. The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke. Med Sci Monit 2013;19:548-70.

(41) El-Sharkawy AM, Sahota O, Maughan RJ, Lobo DN. Hydration in the older hospital patient - is it a problem? Age Ageing 2014;43:i33-i35.

(42) Masento NA, Golightly M, Field DT, Butler LT, van Reekum CM. Effects of hydration status on cognitive performance and mood. Br J Nutr 2014;111:1841-52.

(43) Watson P, Whale A, Mears SA, Reyner LA, Maughan RJ. Mild hypohydration increases the frequency of driver errors during a prolonged, monotonous driving task. Physiology & Behavior 2015;147:313-8.


(44) Bunn D, Jimoh FO, Howard Wilsher S, Hooper L. Increasing fluid intake and reducing dehydration risk in older people living in long-term care: a systematic review. J Am Med Dir Assoc 2015;16(2):101-13.

(45) Abdelhamid A, Bunn D, Dickinson A, Killett A, Poland F, Potter J, et al. Effectiveness of interventions to improve, maintain or faciltate oral food and/or drink intake in people with dementia. PROSPERO 2014;CRD42014007611 :http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014007611 .


http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014007611

Table 1. Characteristics of DRIE study participants

Characteristic All 188 DRIE

participants

Mean (SD), n

Hydration status

Current

Dehydration

Mean (SD), n

Impending

Dehydration

Mean (SD), n

Hydrated

Mean (SD), n

Serum Osmolality,

mOsm/kg

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

prescriptions

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

drinks/day

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


Table 2. Results of multivariate regressions for the full DRIE dataset (in 188 participants).

Type of indicator

Linear regression on serum osmolality*

Logistic regression on impending dehydration (90 people have impending or current dehydration)

Logistic regression on current dehydration (38 people have current dehydration)

Measure Coefficient (95% CI),

p-value

Measure Odds ratio (95%

CI), p-value

Measure Odds ratio (95% CI),

p-value

Renal function

eGFR -0.09 (-0.15 to -0.03)

p=0.005

eGFR 0.98 (0.96 to 0.99)

p=0.007

eGFR 0.98 (0.95 to 1.00)

p=0.045

Cognitive function

MMSE score -0.37 (-0.56 to -0.18)

p<0.001

MMSE

score

0.93 (0.88 to 0.98)

p=0.010

MMSE drawing

sub-score

0.26 (0.11 to 0.65)

p=0.004

Diabetic status

Uses diabetic

medication

6.72 (3.39 to 10.04)

p<0.001

Diabetic

status

3.77 (1.59 to 8.93)

p=0.003

Use of any

diabetic

medication

6.77 (2.18 to 21.04)

p=0.001

Other factors Potassium-

sparing

diuretic

-4.93 (-9.09 to -0.77)

p=0.021

sex 2.00 (1.01 to 3.97)

p=0.047

Healthcare

contacts in past

2 months

1.07 (1.01 to 1.13)

p=0.027

*Serum osmolality = 306.0 – (0.086*eGFR) – (0.37 *MMSE) + 6.72 if uses diabetic medication – 4.93 if uses potassium-sparing diuretics


Figure captions

Figure 1. Flow diagram for the Dehydration Recognition In our Elders (DRIE) study


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


Figure 3. Box plot of serum osmolality for those who expressed thirst, and those who said

they were not thirsty, just before venepuncture.


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


http://www.researchregister.org.uk/

ueaeprints.uea.ac.uk · web viewthis paper summarises independent research funded by the national...

Documents