Impaired hydration status in acutely admitted older patients: prevalence and impact on mortality

Abstract

Background impaired hydration is common in the older people, however studies of its effects on outcome in the acute setting are limited. Objectives to assess (i) the prevalence of impaired hydration, (ii) its relationship with laboratory markers of altered hydration and with (iii) short- and long-term mortality. Design retrospective cohort study. Setting University Hospital-Internal Medicine Department. Subjects a total of 5,113 older patients consecutively acutely admitted from October 2015 to July 2016. Methods according to calculated serum osmolarity at admission hydration status was stratified in: low osmolarity (<275 mmol/L), euhydration (275–295 mmol/L), impending (296–300 mmol/L) and current dehydration (>300 mmol/L). Relationships with serum sodium, potassium, glucose, urea, estimated glomerular filtration rate (eGFR), haematocrit, urea/creatinine ratio (Urea/Cr) and urine specific gravity (USG) were determined. Charlson Comorbidity Index, Modified Early Warning Score, Glasgow Prognostic Score, Norton score and Nutritional Risk Screening-2002 were calculated. Results current and impending dehydration, euhydration and low-osmolarity were detected in 51.7, 17.1, 28.5 and 2.7% of the patients, respectively. Osmolarity correlated with urea (r = 0.846). Associations with serum sodium, creatinine, eGFR and urea/Cr were low but significant, being negligible that with USG and haematocrit. Serum sodium and urea increased in the transition from low- to high-osmolarity (P < 0.001 in all pairwise comparisons). In multivariate modelling current dehydration, functional dependence, clinical instability and high nutritional risk were associated (P < 0.001) with reduced short- and long-term survival. Conclusions impaired hydration is common in older people acutely admitted to medical care and is associated with poor outcome. Early assessment of calculated serum osmolarity is mandatory to target dehydration and hypoosmolar disorders.

Predictors of short- and long-term mortality among acutely admitted older patients: role of inflammation and frailty

“…Impaired hydration is easily diagnosed by serum osmolality or alternatively by calculated serum osmolarity by validated formulas [24,25]. Dehydration may develop quickly in those at increased risk with life-threatening consequences both in hospital after discharge [22,[26][27][28]. Rapid identification of this condition allows to establish a prompt treatment, which results in complete reversibility in mild and impending forms.…”

“…Another useful assessment is that of hydration status, since dehydration is common in hospitalized older adults ranging from over one third to 50% of geriatric adults admitted to the hospital as emergencies [ 22 , 23 ]. Impaired hydration is easily diagnosed by serum osmolality or alternatively by calculated serum osmolarity by validated formulas [ 24 , 25 ].…”

Literature Review Hydration Assessment Methods in the Elderly Population: Advantages and Disadvantages

“…The result obtained using this formula is in mmol/L and is classified based on the calculated serum osmolarity levels: (i) normal hydration range Hydration Assessment Methods in… (275-295 mmol/L), (ii) potential dehydration (296-300 mmol/L), (iii) established dehydration (>300 mmol/L), and (iv) low osmolarity (<275 mmol/L) (Sanson et al, 2021).…”

“…Blood sampling methods may not be the most suitable parameter for field research as blood sampling is considered an invasive procedure for subjects (Baron et al, 2015). Although serum osmolality is a good marker for assessing acute changes in hydration status in the elderly, it should be noted that this assessment does not represent chronic hydration as the values are constantly changing (Sanson et al, 2021). Additionally, this method also incurs high laboratory costs and time, requires a long processing time, and may be impractical for the elderly population due to their vulnerable health status (Barley, Chapman and Abbiss, 2020).…”

Hydration Status in Older Adults: Current Knowledge and Future Challenges

“…Dehydration has been shown to affect cognitive performance, and increase risk of metabolic and renal diseases. It represents an independent factor of hospital length of stay, readmission, intensive care, in-hospital mortality, and poor prognosis [12,[15][16][17][18].…”