Low-Intake Dehydration in Older Adults: Prevalence, Outcomes and Interventions
Meta-analyses report low-intake dehydration in 24% of non-hospitalised older adults and 34% of long-term-care residents (Parkinson 2023) and, as a suggested pooled estimate, 23% of hospitalised older adults at or near admission (Hooper 2026, where 5039 of 14,398 participants, 35%, were dehydrated across the included studies); a systematic review reports dehydration associated with higher mortality and longer hospital stays (Edmonds 2021); intervention groups consumed 300.93 mL more fluid a day than usual care in a meta-analysis of 2 studies, which reports limited evidence overall and concludes that behavioural interventions “appear promising for improving hydration” (Bruno 2021); and serum osmolality is described as the gold standard for assessment (Lambert 2022).
What the evidence says
The sources on this entry are meta-analyses of the prevalence of low-intake dehydration in older adults, a systematic review of its outcomes, meta-analyses of interventions to raise fluid intake, and reviews of assessment. Parkinson 2023 (meta-analysis of 61 studies, 22,398 participants) reports that 24% of older people were dehydrated by serum osmolality above 300 mOsm/kg, 34% of long-term-care residents, 19% of those living in the community and 37% of those with more pre-existing illnesses, and concludes that low-intake dehydration is common in non-hospitalised older adults. Hooper 2026 (meta-analysis of 19 studies, 14,398 hospitalised participants) reports 35% dehydrated at or near admission, with a pooled prevalence of 23%, and concludes that it is highly prevalent among hospitalised older adults at admission. Edmonds 2021 (systematic review of 18 papers, 33,707 participants) reports dehydration associated with higher mortality, worsened frailty, longer hospital stays, worse surgical recovery and a possible neurocognitive impact; Li 2023 (narrative review) reports dehydration as an independent factor for hospital length of stay, readmission, ICU admission and in-hospital mortality; Lambert 2022 (narrative review) reports that geriatric dehydration is not benign. On interventions, Bruno 2021 (meta-analysis of 2 studies, 165 participants, from 19 reviewed) reports that intervention groups consumed 300.93 mL more fluid per day than usual care with no heterogeneity, and concludes that the evidence is limited and that behavioural interventions appear promising; Atasoy 2025 (meta-analysis of 5 studies) reports a significant increase in total daily fluid intake and urine volume with nurse-led self-hydration interventions. On assessment, Lambert 2022 reports that skin turgor, dry mouth and urine colour or specific gravity are “not recommended for assessment” and that serum osmolality is the gold standard; Hooper 2015 is a systematic review of the diagnostic accuracy of clinical signs and tests for water-loss dehydration whose results are not recorded in this library. The 300.93 mL figure is an effect size Bruno 2021 reports, not a dose this entry recommends.
- Myth: Dry mouth or dark urine is a reliable check for dehydration in an older person. Actually: the review reports that skin turgor, dry mouth and urine colour perform poorly in the elderly; serum or plasma osmolality is the reference standard.
- Does not diagnose, treat, or cure any disease or injury
- Not a substitute for individualized medical or physical-therapy advice
- Results vary between individuals; no guaranteed outcome
- Agreement
- Direction recorded for 0 of 8 sources; not yet recorded for the rest.
- The claim's outcome
- Outcome not yet recorded
- Certainty
- No source states a certainty rating.
- Authors
- Sources share authors: L. Hooper (first author of 2 sources); Diane Bunn (senior author of 2 sources).
What each source measured and concluded (8)
- What it measured
- Prevalence of low-intake dehydration in older adults
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review and meta-analysis (quality-effects)
- Studies and participants, as stated
- 61 studies; 22,398 participants (44 studies in meta-analysis)
- What it measured
- Hydration and hydration-linked events (constipation, falls, UTIs) and patient satisfaction
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review and meta-analysis
- Studies and participants, as stated
- 19 studies (978 participants); 2 studies (165 participants) meta-analysed
- Heterogeneity, as stated
- I2=0%, p<0.00001)
- What it measured
- Effects of dehydration on health outcomes, healthcare costs, and cognitive performance
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review (narrative synthesis)
- Studies and participants, as stated
- 18 papers; N=33,707
- What it measured
- Prevalence of low-intake dehydration (serum osmolality/osmolarity >300)
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review and meta-analysis
- Studies and participants, as stated
- 19 studies; 14,398 hospitalised participants
- What it measured
- Effectiveness of self-hydration management interventions (fluid intake, urine volume)
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review and meta-analysis
- Studies and participants, as stated
- 5 studies (from 20 eligible; 1,065 reviewed)
- What it measured
- Diagnostic accuracy of clinical symptoms, signs and tests for water-loss dehydration
- How it was read
- screened only, not extracted
- What it measured
- Consequences of geriatric dehydration and practical guidelines
- How it was read
- screened only, not extracted
- What it measured
- Current knowledge on hydration status and dehydration in older adults
- How it was read
- screened only, not extracted
Each source below is shown with its study design and a link to the original study, or, where it is not a completed research paper, with what kind of record it is; those are not counted. This is the audit trail.
Why do some records show a record type instead of a study design?
A study design is shown for a completed, peer-reviewed paper. A registered protocol, a preprint, a conference abstract, a referee report or a book chapter has not been through peer review as a finished paper, so it is labelled for what it is, and it is counted in no source count. Where a record could not be confirmed as a completed paper at all, it says so rather than guessing. They all stay in the list, and their DOI still resolves, because the count of what was screened is part of the audit trail.
- Protocol / registration A registered plan for a review or trial, not its results.
- Preprint Posted by its authors before peer review.
- Conference abstract A conference summary rather than a peer-reviewed paper.
- Peer-review report A referee's report on a paper, not the paper itself.
- Guideline / position stand A recommendation derived from evidence, which is a step further from the data than the evidence itself.
- Book chapter A chapter in a scholarly book rather than a journal paper.
- Type not recorded Our record does not say what kind of publication this is, so it is counted in no source count. That is a gap in our data, not a judgement about the research.