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• Serum osmolality may fluctuate with changes in fluid volume status associated with neurohormonal dysregulation that occurs in heart failure. • Heart failure related fatigue is associated with lower serum osmolality. • Women have higher odds of experiencing heart failure related fatigue compared to men. Fatigue is a prominent symptom of heart failure (HF). However, underlying mechanisms remain poorly understood. Fluid volume status has been suggested as a physiologic mechanism of HF-related fatigue. Serum osmolality may fluctuate with changes in volume status associated with neurohormonal dysregulation. The relationship of fatigue to serum osmolality has not been assessed in adults with HF. Describe the relationship between serum osmolality and fatigue in adults with HF. We analyzed two waves of cross-sectional data from the National Health and Nutrition Examination Survey (2015–2016 and 2017–2018). Adults who self-reported having HF without select co-morbid conditions known to contribute to fatigue were included. Data were weighted to provide US national estimates, and complex sample design used for analyses. Sequential logistic regression was used to isolate the effect of serum osmolality on the odds of having fatigue. Data from the sample represented 1.4 million Americans with HF (58.5 % male; median age 68 years), of whom 1,001,589 (67.9 %) reported fatigue. Participants with fatigue had lower serum osmolality compared to those without fatigue (t = -3.04, p =.009). Higher serum osmolality was associated with 8.8 % lower odds of experiencing fatigue when controlling for sex and body mass index (OR = 0.912, p =.007, CI 0.857 - 0.972). HF-related fatigue is associated with lower serum osmolality. Low serum osmolality may indicate excess volume and the presence of a heightened neurohormonal response, both of which may influence fatigue. Alternatively, serum osmolality may directly affect other physiologic changes that may contribute to fatigue. [ABSTRACT FROM AUTHOR]

Background: To investigate the association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction (AMI). Methods: Three thousand eight hundred eighty-five AMI patients from the Medical Information Mart for Intensive Care IV were enrolled for this study. The primary outcome was deteriorating renal function. Secondary outcomes included the new-onset of acute kidney injury (AKI) and progress of AKI. < 293.2725 mmol/L was defined as low serum osmolality, and ≥ 293.2725 mmol/L as high serum osmolality based on upper quartile. Univariate and multivariate logistic regression models were used to explore the associations between serum osmolality and the development of deteriorating renal function, the new-onset of AKI and progress of AKI among AMI patients. Subgroup analysis was also conducted. Results: One thousand three hundred ninety-three AMI patients developed deteriorating renal function. After adjusting all confounding factors, high serum osmolality was associated with increased risk of deteriorating renal function [odds ratio (OR) = 1.47, 95% confidence interval (CI): 1.22–1.78], new-onset of AKI (OR = 1.31, 95% CI: 1.01–1.69), and progress of AKI risk (OR = 1.26, 95% CI: 1.01–1.59) among AMI patients. In addition, when the stratified analysis was performed for age, AMI type, cardiogenic shock, and estimated glomerular filtration rate (eGFR), high serum osmolality was risk factor for the risk of deteriorating renal function among patients aged 65 years or older, without cardiogenic shock, and with an eGFR ≥ 60 mL/min/1.73m2. Conclusion: Higher serum osmolality increased the risk of deteriorating renal function among AMI patients. [ABSTRACT FROM AUTHOR]

Abstract Background To investigate the association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction (AMI). Methods Three thousand eight hundred eighty-five AMI patients from the Medical Information Mart for Intensive Care IV were enrolled for this study. The primary outcome was deteriorating renal function. Secondary outcomes included the new-onset of acute kidney injury (AKI) and progress of AKI.

Aim: This study aimed to analyze the association between serum osmolality and the risk of in-hospital mortality in intracerebral hemorrhage (ICH) patients. Methods: In this retrospective cohort study, data of a total of 1,837 ICH patients aged =18 years were extracted from the Medical Information Mart for Intensive Care-IV (MIMIC-IV). Serum osmolality and blood urea nitrogen (BUN)-to-creatinine (Cr) ratio (BCR) were used as the main variables to assess their association with the risk of in-hospital mortality in ICH patients after first intensive care unit (ICU) admission using a univariable Cox model. Univariable and multivariable Cox regression analyses were applied to explore the associations between serum osmolality, BCR, and in-hospital mortality of ICH patients. Hazard ratio (HR) and 95% confidence intervals (CIs) were calculated. Results: The median survival duration of all participants was 8.29 (4.61-15.24) days. Serum osmolality of =295 mmol/L was correlated with an increased risk of in-hospital mortality in patients with ICH (HR = 1.43, 95%CI: 1.14-1.78). BCR of >20 was not significantly associated with the risk of in-hospital mortality in ICH patients. A subgroup analysis indicated an increased risk of in-hospital mortality among ICH patients who were women, belonged to white or Black race, or had complications with acute kidney injury (AKI). Conclusion: High serum osmolality was associated with an increased risk of inhospital mortality among ICH patients. [ABSTRACT FROM AUTHOR]

Background: Previous studies have not thoroughly explored the impact of serum osmolality levels on early mortality in heart failure and reduced ejection fraction (HFrEF) patients. The purpose of this study was to investigate the relationship between serum osmolality levels and early all-cause mortality in patients with HFrEF. Methods: The open access MIMIC-IV database was the source of data for our study. We collected demographic data, vital signs, laboratory parameters, and comorbidities of the included patients and divided them into 3 groups based on their initial serum osmolality on admission, with the primary outcome being allcause mortality within 28 days of admission. Smoothing Spline Fitting Curve, the Kaplan-Meier survival curve, and Threshold effect analysis were used to assess the relationship between serum osmolality and early mortality in HFrEF patients. Results: A total of 6228 patients (55.31% male) were included. All-cause mortality within 28 days on admission was 18.88% in all patients. After adjusting for confounders, higher serum osmolality levels were independently associated with an increased risk of 28-days all-cause mortality compared with the reference group (Reference group Q2: 290--309 mmol/L, Q4: HR, 1.82 [95% CI 1.19--2.78] P<0.05, Q5: HR, 1.99 [95% CI 1.02--3.91] P<0.05). Smooth spline fitting revealed a U-shaped association between serum osmolality and 28-days all-cause mortality. Further threshold effect analysis results suggested that each unit increase in serum osmolality level was associated with a 2% increase in 28- days all-cause mortality when serum osmolality levels were ≥ 298.8 mmol/L (HR, 1.019 [95% CI 1.012--1.025] P<0.05). Conclusion: A U-shaped correlation between initial serum osmolality and 28- days all-cause mortality in HFrEF patients was identified, revealing higher osmolality levels significantly increase mortality risk. These results underscore serum osmolality's critical role in early mortality among HFrEF patients, highlighting the need for further, larger-scale studies for validation. [ABSTRACT FROM AUTHOR]

Background: Progressive ischemic brain injury after cardiac arrest can cause damage to the hypothalamic-pituitary axis, particularly the pituitary gland. This may impact serum osmolality (SOsm) and urine osmolality (UOsm) in patients who have experienced out-ofhospital cardiac arrest (OHCA). We assumed that a low ratio of UOsm to SOsm (USR) is related to poor outcomes among OHCA patients. Therefore, the present study was designed to evaluate the association between the USR within 72 h after the restoration of spontaneous circulation (ROSC) and 6-month neurological outcomes in OHCA patients. Methods: This prospective, observational study included OHCA patients with targeted temperature management at Chonnam National University Hospital in Gwangju, Korea, between January 2016 and December 2022. We collected SOsm and UOsm data at admission (T0) and 24 (T1), 48 (T2), and 72 h (T3) after ROSC. The primary outcome was a poor neurological outcome at 6 months defined by cerebral performance categories 3, 4, or 5. Results: This study included 319 patients. The mean UOsm and USRs at T0, T1, T2, and T3 of patients with poor outcomes were lower than those of patients with good outcomes. Multivariable analysis indicated that the USRs at T1 (odds ratio [OR], 0.363; 95% confidence interval [CI], 0.221-0.594), T2 (OR, 0.451; 95% CI, 0.268-0.761), and T3 (OR, 0.559; 95% CI, 0.357-0.875) were associated with a poor outcome. The areas under the receiver operating characteristic curves of USRs at T0, T1, T2, and T3 for predicting poor outcomes were 0.615 (95% CI, 0.559-0.669), 0.711 (95% CI, 0.658-0.760), 0.724 (95% CI, 0.671-0.772), and 0.751 (95% CI, 0.699-0.797), respectively. Conclusions: The USRs within 72 h of ROSC were associated with poor neurological outcomes at 6 months in OHCA patients. [ABSTRACT FROM AUTHOR]

BackgroundPrevious studies have not thoroughly explored the impact of serum osmolality levels on early mortality in heart failure and reduced ejection fraction (HFrEF) patients. The purpose of this study was to investigate the relationship between serum osmolality levels and early all-cause mortality in patients with HFrEF.MethodsThe open access MIMIC-IV database was the source of data for our study. We collected demographic data, vital signs, laboratory parameters, and comorbidities of the included patients and divided them into 3 groups based on their initial serum osmolality on admission, with the primary outcome being all-cause mortality within 28 days of admission. Smoothing Spline Fitting Curve, the Kaplan-Meier survival curve, and Threshold effect analysis were used to assess the relationship between serum osmolality and early mortality in HFrEF patients.ResultsA total of 6228 patients (55.31% male) were included. All-cause mortality within 28 days on admission was 18.88% in all patients. After adjusting for confounders, higher serum osmolality levels were independently associated with an increased risk of 28-days all-cause mortality compared with the reference group (Reference group Q2: 290–309 mmol/L, Q4: HR, 1.82 [95% CI 1.19–2.78] P

Summary: Background: In 2019 ESPEN released a guideline on clinical nutrition and hydration in geriatrics. Several knowledge gaps were also identified. Among these were a question about whether there is an overlap of low-intake dehydration with malnutrition in older adults. The aim of this article is to take a closer look at this potential overlap between low-intake dehydration and malnutrition and whether it is of relevance to clinical practice. Methods: A non-systematic review of the literature. Results: The literature review identified an overlap between, respectively, malnutrition and low-intake dehydration, regarding the definitions, the risk factors and the consequences. However, although both conditions have serious consequences for older adults, very limited research has been performed on the aspect of low-intake dehydration compared to the aspect of malnutrition. Conclusion: Further research is needed to see if there is an overlap between the two conditions in clinical practice.

Abstract Background Water intake and hydration status have been suggested to impact cognition; however, longitudinal evidence is limited and often inconsistent. This study aimed to longitudinally assess the association between hydration status and water intake based on current recommendations, with changes in cognition in an older Spanish population at high cardiovascular disease risk. Methods A prospective analysis was conducted of a cohort of 1957 adults (aged 55–75) with overweight/obesity (BMI between ≥ 27 and < 40 kg/m2) and metabolic syndrome from the PREDIMED-Plus study. Participants had completed bloodwork and validated, semiquantitative beverage and food frequency questionnaires at baseline, as well as an extensive neuropsychological battery of 8 validated tests at baseline and 2 years of follow-up. Hydration status was determined by serum osmolarity calculation and categorized as < 295 mmol/L (hydrated), 295–299.9 mmol/L (impending dehydration), and ≥ 300 mmol/L (dehydrated). Water intake was assessed as total drinking water intake and total water intake from food and beverages and according to EFSA recommendations. Global cognitive function was determined as a composite z-score summarizing individual participant results from all neuropsychological tests. Multivariable linear regression models were fitted to assess the associations between baseline hydration status and fluid intake, continuously and categorically, with 2-year changes in cognitive performance. Results The mean baseline daily total water intake was 2871 ± 676 mL/day (2889 ± 677 mL/day in men; 2854 ± 674 mL/day in women), and 80.2% of participants met the ESFA reference values for an adequate intake. Serum osmolarity (mean 298 ± 24 mmol/L, range 263 to 347 mmol/L) indicated that 56% of participants were physiologically dehydrated. Lower physiological hydration status (i.e., greater serum osmolarity) was associated with a greater decline in global cognitive function z-score over a 2-year period (β: − 0.010; 95% CI − 0.017 to − 0.004, p-value = 0.002). No significant associations were observed between water intake from beverages and/or foods with 2-year changes in global cognitive function. Conclusions Reduced physiological hydration status was associated with greater reductions in global cognitive function over a 2-year period in older adults with metabolic syndrome and overweight or obesity. Future research assessing the impact of hydration on cognitive performance over a longer duration is needed. Trial registration International Standard Randomized Controlled Trial Registry, ISRCTN89898870. Retrospectively registered on 24 July 2014

BackgroundChronic dehydration is associated with complications and mortality in acute ischemic stroke patients. Prior literature indicates that farmers and fishery workers are commonly affected by cardiometabolic diseases and there is a need for early prevention of stroke. This study explores the prevalence of dehydration and the association of cardiometabolic risk profiles in agricultural and aquaculture workers.MethodsWe conducted a community-based, cross-sectional study of agriculture and aquaculture workers in Yunlin County of Taiwan between August 1 and December 31, 2021. Data on demographic characteristics and health-related lifestyles were collected through one-on-one interviews using a questionnaire. The threshold for dehydration is defined as serum osmolality ≥295 mOsm/kg, and physiological biomarkers were collected from a collaborating hospital. Multivariable logistic regression analyses adjusted for demographic characteristics were performed to investigate the association between dehydration levels, cardiometabolic risks, and health-related behaviors.ResultsA total of 962 Taiwanese agriculture and aquaculture workers who were predominantly women (65%) with a mean age of 64 years (SD = 13.8) were enrolled. The findings showed a high prevalence of dehydration (36%), metabolic syndrome (44.5%), abnormal waist circumference (64.4%), and abnormal blood pressure (68.5%). Multivariate logistic regression demonstrated that dehydration was significantly associated with metabolic syndrome (p

Background: Patient undergoing percutaneous coronary intervention (PCI) are at high risk of Contrast induced nephropathy (CIN). Calculated pre procedure serum osmolality has been demonstrated to be clinically useful for prediction of CIN after PCI. Objective: The aim of this study was to find the association of calculated pre-procedure serum osmolality with the development of CIN among patients undergoing PCI. Methods: This cross-sectional observational study was carried out in the Department of Cardiology, National Heart Foundation Hospital and Research Institute, Mirpur, Dhaka. Total 280 consecutive patients with coronary artery disease undergone PCI within the study period were included in this study. Serum osmolality was calculated from laboratory results obtained before PCI using the following equation: [Osmolality=2Na +1.15(glucose in mg/18+urea/6]. Based on development of CIN, patients were divided into two groups. A Total of 36 Patient with CIN were included in group I and those 244 patients who did not develop CIN were included in group II. Results: In our study over all Incidence of CIN was 12.9%. mean serum osmolality of the patient with CIN was 304.65±6.71 and 295.64±8.48 in a patient without CIN which is a statistically significant difference with a P-value <0.001. On multivariate logistic regression to clarify the independent association of CIN shows that after the effect of other variables serum osmolality is independently associated with CIN, OR 1.162 (95% CI; 1.087-1.243, P-value <0.001). ROC curve for calculated pre-procedure serum osmolality of the study population showed the area under the curve (AUC) is 0.794 (95% CI;0.710-0.879, P-value <0.001). The cutoff value of serum osmolarity for CIN prediction was >302.75 with a sensitivity of 72.2% and a specificity of 82.8%. Conclusion: High calculated pre procedure serum osmolality is significantly associated with development CIN after percutaneous coronary intervention. [ABSTRACT FROM AUTHOR]

Purpose: Suboptimal hydration has been linked to a variety of adverse health outcomes. Few studies have examined the impact of hydration status on immune function, a plausible physiological mechanism underlying these associations. Therefore, we tested how variation in hydration status was associated with circulating pro-inflammatory cytokine levels and ex vivo lipopolysaccharide (LPS)-stimulated pro-inflammatory cytokine production. Methods: Blood samples were obtained from a community sample of healthy middle-to-older-aged adults (N = 72). These samples were used to assess serum osmolality, a biomarker of hydration status, and markers of immune function including circulating pro-inflammatory cytokines and stimulated pro-inflammatory cytokine production after 4 and 24 h of incubation with LPS. Multiple linear regressions were used to test the association between serum osmolality (as a continuous variable) and markers of immune function at baseline and after 4 and 24 h adjusting for age, sex, and BMI. These models were re-estimated with serum osmolality dichotomized at the cut-off for dehydration (> 300 mOsm/kg). Results: While not significantly associated with circulating cytokines (B = − 0.03, p = 0.09), serum osmolality was negatively associated with both 4 h (B = − 0.05, p = 0.048) and 24 h (B = − 0.05, p = 0.03) stimulated cytokine production when controlling for age, sex, and BMI. Similarly, dehydration was associated with significantly lower cytokine production at both 4 h (B = − 0.54, p = 0.02) and 24 h (B = − 0.51, p = 0.02) compared to adequate hydration. Conclusion: These findings suggest that dehydration may be associated with suppressed immune function in generally healthy middle-to-older aged community-dwelling adults. Further longitudinal research is needed to more clearly define the role of hydration in immune function. [ABSTRACT FROM AUTHOR]

Serum osmolality is the sum of the osmolalities of every single dissolved particle in the blood such as sodium and associated anions, potassium, glucose, and urea. Under normal conditions, serum sodium concentration is the major determinant of serum osmolality. Effective blood osmolality, so-called blood tonicity, is created by the endogenous (e.g., sodium and glucose) and exogenous (e.g., mannitol) solutes that are capable of creating an osmotic gradient across the membranes. In case of change in effective blood osmolality, water shifts from the compartment with low osmolality into the compartment with high osmolarity in order to restore serum osmolality. The difference between measured osmolality and calculated osmolarity forms the osmolal gap. An increase in serum osmolal gap can stem from the presence of solutes that are not included in the osmolarity calculation, such as hypertonic treatments or toxic alcoholic ingestions. In clinical practice, determination of serum osmolality and osmolal gap is important in the diagnosis of disorders related to sodium, glucose and water balance, kidney diseases, and small molecule poisonings. As blood hypertonicity exerts its main effects on the brain cells, neurologic symptoms varying from mild neurologic signs and symptoms to life-threatening outcomes such as convulsions or even death may occur. Therefore, hypertonic states should be promptly diagnosed and cautiously managed. In this review, the causes and treatment strategies of hyperosmolar conditions including hypernatremia, diabetic ketoacidosis, hyperglycemic hyperosmolar syndrome, hypertonic treatments, or intoxications are discussed in detail to increase awareness of this important topic with significant clinical consequences. [ABSTRACT FROM AUTHOR]

The association between serum osmolality, an effective indicator of body hydration status, and long-term mortality in the general population remains undetermined. The present study aimed to investigate the association of serum osmolality with long-term all-cause and cardiovascular mortality among adults in the United States. This cohort study used data from the National Health and Nutrition Examination Survey (NHANES) 2007–2014. Participants were linked to National Death Index mortality data from the survey date through December 31, 2019. Cox proportional hazards regression model was used to calculate hazard ratios (HRs) and 95% CIs, and restricted cubic spline (RCS) regression was conducted. A total of 18312 US adults were included. During a median follow-up of 8.7 years, 1353 total deaths occurred, including 379 cardiovascular deaths. After multivariable adjustments, compared with the 3rd quartile (Q3) of serum osmolality, participants in the 1st (Q1) and 4th (Q4) quartiles were at a significantly higher risk of all-cause mortality (HR 1.41 [95% CI, 1.14–1.75] and 1.29 [95% CI, 1.04–1.61], respectively). RCS revealed a nonlinear relationship of serum osmolality to all-cause and cardiovascular mortality, with an inflection point of 278 mmol/kg. In the nationally representative cohort of US adults, serum osmolality was nonlinearly associated with all-cause and cardiovascular mortality. The risk of mortality was lowest around an osmolality of 278 mmol/kg. These findings suggest the importance of serum osmolality management for long-term health outcomes. • Serum osmolality was associated with long-term mortality. • The relationship between serum osmolality and all-cause mortality was nonlinear. • The risk of mortality was lowest around an osmolality of 278 mmol/kg. [ABSTRACT FROM AUTHOR]

Background: Water intake and hydration status have been suggested to impact cognition; however, longitudinal evidence is limited and often inconsistent. This study aimed to longitudinally assess the association between hydration status and water intake based on current recommendations, with changes in cognition in an older Spanish population at high cardiovascular disease risk. Methods: A prospective analysis was conducted of a cohort of 1957 adults (aged 55–75) with overweight/obesity (BMI between ≥ 27 and < 40 kg/m2) and metabolic syndrome from the PREDIMED-Plus study. Participants had completed bloodwork and validated, semiquantitative beverage and food frequency questionnaires at baseline, as well as an extensive neuropsychological battery of 8 validated tests at baseline and 2 years of follow-up. Hydration status was determined by serum osmolarity calculation and categorized as < 295 mmol/L (hydrated), 295–299.9 mmol/L (impending dehydration), and ≥ 300 mmol/L (dehydrated). Water intake was assessed as total drinking water intake and total water intake from food and beverages and according to EFSA recommendations. Global cognitive function was determined as a composite z-score summarizing individual participant results from all neuropsychological tests. Multivariable linear regression models were fitted to assess the associations between baseline hydration status and fluid intake, continuously and categorically, with 2-year changes in cognitive performance. Results: The mean baseline daily total water intake was 2871 ± 676 mL/day (2889 ± 677 mL/day in men; 2854 ± 674 mL/day in women), and 80.2% of participants met the ESFA reference values for an adequate intake. Serum osmolarity (mean 298 ± 24 mmol/L, range 263 to 347 mmol/L) indicated that 56% of participants were physiologically dehydrated. Lower physiological hydration status (i.e., greater serum osmolarity) was associated with a greater decline in global cognitive function z-score over a 2-year period (β: − 0.010; 95% CI − 0.017 to − 0.004, p-value = 0.002). No significant associations were observed between water intake from beverages and/or foods with 2-year changes in global cognitive function. Conclusions: Reduced physiological hydration status was associated with greater reductions in global cognitive function over a 2-year period in older adults with metabolic syndrome and overweight or obesity. Future research assessing the impact of hydration on cognitive performance over a longer duration is needed. Trial registration: International Standard Randomized Controlled Trial Registry, ISRCTN89898870. Retrospectively registered on 24 July 2014 [ABSTRACT FROM AUTHOR]

Objective: To observe the changes of osmolarity levels due to fasting in Ramadan among type 2 diabetic patients. Method: The observational study was conducted from May 16 to June 3, 2019, at the Istanbul Medeniyet University, Istanbul, Turkey, and comprised adult type 2 diabetic patients of either gender visiting the diabetes outpatient clinics during the holy month of Ramadan. Those fasting were placed in Group A, while those not fasting formed Group B. Anthropometric measurements and medications in use were recorded. Blood samples were taken in the morning and before the evening meal. Serum osmolality was calculated using serum levels of sodium, glucose and blood urea nitrogen. Data was analysed using SPSS 16. Results: Of the 52 patients, 27(52%) were in Group A and 25(48%) were in Group B. Overall, there were 22(42%) females and 30(58%) males. The mean morning serum osmolalities of the two groups were not different (p>0.05). The mean evening serum osmolality was not significantly different than the mean morning osmolality in Group A (p=0.22). In Group B, the mean evening serum osmolality was significantly lower than the mean morning osmolality (p=0.004). No significant difference was found between mean morning and evening serum osmolalities of those taking sodium-glucose cotransporter 2 (p>0.05). Conclusion: There was no biochemical sign of dehydration with Ramadan fasting in type 2 diabetes mellitus patients. Clinical Trial Number: [NCT04392570] Link: https://clinicaltrials.gov/ Key Words: Fasting, Serum osmolality, Ramadan, Type 2 diabetes mellitus, SGLT-2 inhibitors.

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The review presents data on the effect of program hemodialysis on the state of intraocular pressure in patients with terminal chronic renal failure. Treatment with hemodialysis is accompanied by various effects: from intraocular pressure drop to the development of ophthalmic hypertension with pain syndrome. The state of the iris-corneal angle, neovascularization of the structures of the eye drainage system and the presence of glaucoma are significant, but not indisputable, risk factors for pain-related dialysis ophthalmic hypertension. Their combination with the effect on the osmolar balance of dialysis therapy increases the possibility of the formation of ocular hypertension syndrome formation. The need to eliminate dialysis eye pains and the chance of glaucoma progression due to dialysis-affected fluctuations of intraocular pressure remains relevant.

OBJECTIVE: The aim of the study was to find the significance of several factors with parameters of urine tests and blood tests. Finally, we aimed at evaluating the percentage of athletes from the study sample regarding their hydration level. SUBJECTS AND METHODS: The current study is the prospective type and was conducted on Chinese athletes between June 2021 to April 2022. The study was done in 2 parts for obtaining measurements in the summer season and the winter season and then they were correlated between them. Urine and blood samples were evaluated for determining the required parameters. The parameters of the physical environment like temperature, relative humidity, precipitation, etc. were obtained from the concerned weather station for each day. RESULTS: It was observed that 14.5%, 59% and 26.5% of the female participants were found to have hyper-hydrated, euhydrated and dehydrated, respectively. While 17.57%, 69.69% and 12.74% of the males were classified as hyper-hydrated, euhydrated and dehydrated, respectively. The participants with hyper-hydrated were found to have increased urine volume (p<0.001), reduced specific gravity (p<0.001) and reduced-sodium level (p<0.001). CONCLUSIONS: The study found that there is a significant difference in sodium levels between gender and seasons. The level of serum osmolality is also significantly different between the whole study populations concerning combined seasons. In this way, many other parameters are evaluated by correlation with seasons and gender. Hence, this study has brought forward various important findings and gives an overall evaluation of hydration status. [ABSTRACT FROM AUTHOR]

Hyponatremia is defined as serum sodium less than 135 mEq/L and is principally a result of water excess relative to total body sodium content. The evaluation of hyponatremia is incomplete without a careful assessment of the patient's volume status, history, and acquisition of both serum and urine osmolality and sodium studies. Many of these studies can be affected by various clinical factors, and these nuances should be considered while interpreting the results. This is because these results guide the etiologic diagnosis of hyponatremia and consequently its management. In this report, we describe a 50-year-old male being evaluated for hyponatremia found to have unusual serum/urine osmolality studies but ultimately found to have an unmeasured serum osmole (ethanol) interfering with the interpretation of these results. Clinical scenarios that interfere with serum and urine studies commonly obtained in a hyponatremia evaluation are reviewed and an equation to correct for ethanol's osmotic contribution is described., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Mathias et al.)

Aim: This study aimed to analyze the association between serum osmolality and the risk of in-hospital mortality in intracerebral hemorrhage (ICH) patients., Methods: In this retrospective cohort study, data of a total of 1,837 ICH patients aged ≥18 years were extracted from the Medical Information Mart for Intensive Care-IV (MIMIC-IV). Serum osmolality and blood urea nitrogen (BUN)-to-creatinine (Cr) ratio (BCR) were used as the main variables to assess their association with the risk of in-hospital mortality in ICH patients after first intensive care unit (ICU) admission using a univariable Cox model. Univariable and multivariable Cox regression analyses were applied to explore the associations between serum osmolality, BCR, and in-hospital mortality of ICH patients. Hazard ratio (HR) and 95% confidence intervals (CIs) were calculated., Results: The median survival duration of all participants was 8.29 (4.61-15.24) days. Serum osmolality of ≥295 mmol/L was correlated with an increased risk of in-hospital mortality in patients with ICH (HR = 1.43, 95%CI: 1.14-1.78). BCR of >20 was not significantly associated with the risk of in-hospital mortality in ICH patients. A subgroup analysis indicated an increased risk of in-hospital mortality among ICH patients who were women, belonged to white or Black race, or had complications with acute kidney injury (AKI)., Conclusion: High serum osmolality was associated with an increased risk of in-hospital mortality among ICH patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hu and Sha.)

Background: Previous studies have not thoroughly explored the impact of serum osmolality levels on early mortality in heart failure and reduced ejection fraction (HFrEF) patients. The purpose of this study was to investigate the relationship between serum osmolality levels and early all-cause mortality in patients with HFrEF., Methods: The open access MIMIC-IV database was the source of data for our study. We collected demographic data, vital signs, laboratory parameters, and comorbidities of the included patients and divided them into 3 groups based on their initial serum osmolality on admission, with the primary outcome being all-cause mortality within 28 days of admission. Smoothing Spline Fitting Curve, the Kaplan-Meier survival curve, and Threshold effect analysis were used to assess the relationship between serum osmolality and early mortality in HFrEF patients., Results: A total of 6228 patients (55.31% male) were included. All-cause mortality within 28 days on admission was 18.88% in all patients. After adjusting for confounders, higher serum osmolality levels were independently associated with an increased risk of 28-days all-cause mortality compared with the reference group (Reference group Q2: 290-309 mmol/L, Q4: HR, 1.82 [95% CI 1.19-2.78] P<0.05, Q5: HR, 1.99 [95% CI 1.02-3.91] P<0.05). Smooth spline fitting revealed a U-shaped association between serum osmolality and 28-days all-cause mortality. Further threshold effect analysis results suggested that each unit increase in serum osmolality level was associated with a 2% increase in 28-days all-cause mortality when serum osmolality levels were ≥ 298.8 mmol/L (HR, 1.019 [95% CI 1.012-1.025] P<0.05)., Conclusion: A U-shaped correlation between initial serum osmolality and 28-days all-cause mortality in HFrEF patients was identified, revealing higher osmolality levels significantly increase mortality risk. These results underscore serum osmolality's critical role in early mortality among HFrEF patients, highlighting the need for further, larger-scale studies for validation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zou, Li, Lin, Ma, Wei, Tao, Han and Sun.)

Background: The persistence of high serum osmolality in the early postnatal period is a risk for developing patent ductus arteriosus (PDA). Early aggressive nutrition (EAN), involving total parenteral nutrition (TPN), by which enough concentrations of glucose and amino acids are administered intravenously, is recommended postnatally to improve the neurological prognosis in preterm infants. However, the effects of EAN involving TPN on serum osmolality and the development of a PDA have not been adequately studied., Objectives: Thus, in this study, we aimed to investigate the impact of TPN on serum osmolality and determine whether increased serum osmolality could be associated with a higher incidence of PDA in preterm infants., Methods: In this single-center retrospective observational study, preterm infants born at <28 weeks of gestation who had been admitted to our neonatal intensive care unit (NICU) before (pre-TPN period) and after the introduction of TPN (post-TPN) were included. We reviewed the medical records of these patients, compared the changes in serum osmolality from birth to five days after birth, the clinical background, and the incidence of PDA between these two periods, and analyzed the risk factors. Additionally, the factors affecting the serum osmolality in very preterm infants were examined. The patients who met the intervention criteria of our NICU and received a cyclooxygenase (COX) inhibitor, Indacin ® (Nobelpharma, Tokyo, Japan), within seven days after birth were classified as PDA+; those who could not be identified to have PDA flow by echo and did not receive a COX inhibitor were classified as PDA-., Results: The postnatal day and serum sodium (Na + ) were statistically significantly correlated with a higher serum osmolality. Serum osmolality remained statistically significantly higher in the PDA+ cohort compared with the PDA- cohort after the first day of life. However, no statistically significant differences were observed in serum osmolality after 24 hours of age, weeks of gestational age, birth weight, or incidence of PDA between the pre- and post-TPN periods. The results of the multiple logistic regression analyses revealed that the increased serum osmolality correlated with PDA development., Conclusions: In this study, the serum Na + statistically significantly correlated with a higher serum osmolality. Moreover, the increased serum osmolality correlated with PDA development. Thus, the prevention of hypernatremia might reduce the incidence of PDA. Nonetheless, the findings in this study revealed that no statistically significant differences in serum osmolality were observed between the pre-and post-TPN periods, indicating that TPN had little effect on serum osmolality., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. The ethics committee (EC) of Iwate Medical University issued approval (EC approval number: H28-198). Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Toya et al.)

Purposes: Acute kidney injury (AKI) is a common complication in critically ill patients and is usually associated with poor outcomes. Serum osmolality has been validated in predicting critically ill patient mortality. However, data about the association between serum osmolality and AKI is still lacking in ICU. Therefore, the purpose of the present study was to investigate the association between early serum osmolality and the development of AKI in critically ill patients.Methods: The present study was a retrospective cohort analysis based on the medical information mart for intensive care III (MIMIC-III) database. 20,160 patients were involved in this study and divided into six subgroups according to causes for ICU admission. The primary outcome was the incidence of AKI after ICU admission. The association between early serum osmolality and AKI was explored using univariate and multivariate logistic regression analyses.Results: The normal range of serum osmolality was 285–300 mmol/L. High serum osmolality was defined as serum osmolality >300 mmol/L and low serum osmolality was defined as serum osmolality

Abstract Background Blood urea nitrogen (BUN) is one of the substances that affects the calculated serum osmolality (cSosm). A previous study demonstrated that BUN and cSosm were independently associated with the development of chronic kidney disease (CKD) in patients with preserved kidney function. In advanced CKD stages, there is a concomitant increase in cSosm and BUN levels. However, it remains unclear whether BUN or cSosm levels are related to renal outcomes in patients with moderate to severe kidney dysfunction. The aim of this study was to clarify whether the BUN or cSosm level is associated with kidney disease progression in patients with advanced CKD. Methods In this prospective study, we enrolled 459 patients with CKD (stages 3–5). The composite renal endpoint was end-stage renal disease (ESRD) or death, and ESRD alone was added as an alternative outcome. A Cox proportional hazards model was utilized to determine the risk factors for a poor renal outcome. We adjusted for covariates including estimated glomerular filtration rate (eGFR). The cSosm (mOsm/kg) was calculated using the following formula: (2 × sodium) + (BUN/2.8) + (glucose/18). Results During a median follow-up of 25.8 months, the renal endpoint was observed in 210 patients. Multivariable Cox analysis determined the hazard ratio (HR) [95% confidence interval (CI)] for the composite renal outcome in the second, third, and fourth BUN quartiles were 1.36 (0.72–2.58), 1.87 (0.95–3.66), and 2.66 (1.23–5.76) (P for trend

Background: Progressive ischemic brain injury after cardiac arrest can cause damage to the hypothalamic-pituitary axis, particularly the pituitary gland. This may impact serum osmolality (SOsm) and urine osmolality (UOsm) in patients who have experienced out-of-hospital cardiac arrest (OHCA). We assumed that a low ratio of UOsm to SOsm (USR) is related to poor outcomes among OHCA patients. Therefore, the present study was designed to evaluate the association between the USR within 72 h after the restoration of spontaneous circulation (ROSC) and 6-month neurological outcomes in OHCA patients., Methods: This prospective, observational study included OHCA patients with targeted temperature management at Chonnam National University Hospital in Gwangju, Korea, between January 2016 and December 2022. We collected SOsm and UOsm data at admission (T0) and 24 (T1), 48 (T2), and 72 h (T3) after ROSC. The primary outcome was a poor neurological outcome at 6 months defined by cerebral performance categories 3, 4, or 5., Results: This study included 319 patients. The mean UOsm and USRs at T0, T1, T2, and T3 of patients with poor outcomes were lower than those of patients with good outcomes. Multivariable analysis indicated that the USRs at T1 (odds ratio [OR], 0.363; 95% confidence interval [CI], 0.221-0.594), T2 (OR, 0.451; 95% CI, 0.268-0.761), and T3 (OR, 0.559; 95% CI, 0.357-0.875) were associated with a poor outcome. The areas under the receiver operating characteristic curves of USRs at T0, T1, T2, and T3 for predicting poor outcomes were 0.615 (95% CI, 0.559-0.669), 0.711 (95% CI, 0.658-0.760), 0.724 (95% CI, 0.671-0.772), and 0.751 (95% CI, 0.699-0.797), respectively., Conclusions: The USRs within 72 h of ROSC were associated with poor neurological outcomes at 6 months in OHCA patients., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 The Author(s). Published by IMR Press.)

• Usable osmolality equations were identified by Passing-Bablok regression. • Adjustment for bias produced a higher number of usable candidate equations. • Use equations yielding OG ranges <20 mOsm/kg for a ±10 mOsm/kg limit. Many studies have assessed the predictive accuracy of serum osmolality equations. Different approaches for selecting a usable equation were compared using thirty published equations and patient data from a regional hospital laboratory. Laboratory records were extracted with same-sample results for measured serum osmolality, sodium, potassium, urea and glucose analysed in a regional hospital laboratory between 1/1/2017–31/12/2018. Differences were analysed using Passing-Bablok and difference (Bland-Altman) analysis. Three approaches were compared: the shotgun approach, adjusting for bias, and deriving a novel equation using multivariate analysis. The criteria for success included bias ≤0.7%, a 230 – 400 mOsm/kg range, and osmolal gap (OG) 95% reference limits within ±10 mOsm/kg. The majority of equations produced proportionally negative-biased results. The shotgun approach identified two equations (EQ19, EQ6) with bias ≤0.7% but unworkable OG reference limits. The bias adjustment approach produced several equations with bias ≤ 0.7% and OG reference limits within or equivalent to ±10 mOsm/kg. A novel equation generated by us (1.89Na+ + 1.71 K+ + 1.08 Urea + 1.08 Glucose + 13.7) improved with the adjustment of bias and was not superior to the adjusted published equations. Few published equations are immediately usable. Adjustment of bias derives several usable equations of which the best had OG ranges <20 mOsm/kg. We conclude that adjustment of bias can generate equations of equal or superior performance to that of novel equations. [ABSTRACT FROM AUTHOR]

Context: Copeptin is a surrogate marker for arginine vasopressin (AVP) release in response to hyperosmolal stimuli such as diabetic ketoacidosis (DKA).Objective: The objective of this work is to characterize kinetics of copeptin and osmolality, and their dynamic relationship during rehydration and insulin therapy in children with type 1 diabetes (T1D) and DKA.Design and Setting: A prospective, observational, multicenter study was conducted.Patients and Intervention: Children with T1D admitted for DKA underwent serial serum copeptin and osmolality measurements from start of rehydration at 14 time points during 72 hours.Main Outcome Measures: Measurements included temporal course of copeptin and osmolality (kinetics), relationship between both (dynamics), and association between-subject variability (BSV) (coefficient of variation, CV%).Results: Twenty-eight children (20 newly diagnosed T1D) aged 1 to 16 years were included. Copeptin decreased from 95 pmol/L (95% CI, 55-136 pmol/L) (CV%, 158%) to 9.7 pmol/L (95% CI, 8.1-11.4 pmol/L) (CV%, 31%) with a 50% recovery time (t1/2) of 7.1 hours (range, 5.1-11.5 hours) (114%). Serum osmolality decreased from 321 mOsm/kg (range, 315-327 mOsm/kg) (4%) to 294 mOsm/kg (range, 292-296 mOsm/kg) (1%) with a t1/2 of 4.3 hours (range, 3.0-5.6 hours) (64%). Copeptin levels doubled with each osmolality increase by 15 mOsm/kg (range, 10-21 mOsm/kg) (59%), from 9.8 pmol/L (range, 7.3-12.3 pmol/L) (48%) to 280 mOsm/kg. Copeptin kinetics differed between newly diagnosed and known T1D patients (P = .001), and less between mild vs moderate-severe DKA (P = .04).Conclusions: First, this study characterized for the first time copeptin kinetics and dynamics in the high hyperosmolar range in children with DKA. Second, it revealed significant differences in copeptin kinetics between newly diagnosed and known T1D patients that may be explained by changes at the osmoreceptor and renal AVP receptor level due to longstanding osmotic diuresis and DKA. [ABSTRACT FROM AUTHOR]

Purpose: Risks of dehydration and cognitive decline increase with advancing age, yet the relation between dehydration, water intake, and cognitive performance among older adults remains understudied. Methods: Using data from the 2011–2014 cycles of the Nutrition and Health Examination Survey (NHANES), we tested if calculated serum osmolarity (Sosm) and adequate intake (AI) of water among women (n = 1271) and men (n = 1235) ≥ 60 years old were associated with scores of immediate and delayed recall, verbal fluency, and attention/processing speed. Sosm was categorized as < 285 (hyperhydrated), 285–289, 290–294, 295–300, or > 300 (dehydrated) mmol/L. AI of water was defined as ≥ 2 L/day for women and ≥ 2.5 L/day for men. Results: Women with Sosm between 285 and 289 mmol/L scored 3.2–5.1 points higher on the Digit Symbol Substitution test (DSST) of attention/processing speed than women in other Sosm categories (P values < 0.05). There was evidence of a curvilinear relationship between DSST scores and Sosm among women and men (P values for quadratic terms < 0.02). Meeting an alternative AI on water intake of ≥ 1 mL/kcal and ≥ 1500 mL, but not the sex-specific AI, was associated with scoring one point higher on a verbal fluency test (P = 0.02) and two points higher on the DSST (P = 0.03) among women. Significant negative associations between dehydration or inadequate water intake and test scores were not observed among men. Conclusion: Hydration status and water intake were moderately associated with attention/processing speed among females. Future work should consider the effects of both dehydration and overhydration on cognitive function and investigate potential sex differences in cognitive responses to hydration status. [ABSTRACT FROM AUTHOR]

Background: Serum osmolality levels are measured to determine acid–base and electrolyte imbalance in serum. In cases where measurement is not possible, the serum osmolality value can be calculated by various calculation methods. In this study, we compared the Worthley osmolality calculation method which is used most frequently mentioned in literature and the measurements made with vapor pressure osmometer used in our laboratory. We compared whether there was a difference between the results obtained by measurement and calculation method in different age groups. Methods: 221 serum samples of patients who were admitted to the Eskişehir Osmangazi University Hospital Biochemistry Laboratory between December 2016 and May 2018 were included in this study. Glucose, blood urea nitrogen and sodium values were recorded to determine the calculated osmolality values of the patients. Results: There was a statistically significant difference between the measured osmolality values and the calculated osmolality values of the patients (p < 0.001). When compared according to age groups, there was a significant difference between calculated osmolality values (p = 0.006), but there was no difference in measured osmolality values (p = 0.787) in different age groups. It has been observed that this difference in the calculated osmolality values between the age groups is derived from the adult group (18–65, p < 0.001). Conclusion: Our results showed that it is not reliable to calculate serum osmolality values, especially in the adult age group. According to our results the calculated osmolality values are higher than our measured osmolality values. [ABSTRACT FROM AUTHOR]

Copyright of Online Turkish Journal of Health Sciences (OTJHS) / Online Türk Sağlık Bilimleri Dergisi is the property of Oguz KARABAY and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Antony, J.; Sandeep, K.P.; Aravind, R.; Panigrahi, A., and Balasubramanian, C.P., 2019. Growth, survival, and osmoregulation of Indian white shrimp Penaeus indicus juveniles reared in low salinity amended inland saline groundwater and seawater. In: Jithendran, K.P.; Saraswathy, R.; Balasubramanian, C.P.; Kumaraguru Vasagam, K.P.; Jayasankar, V.; Raghavan, R.; Alavandi, S.V., and Vijayan, K.K. (eds.), BRAQCON 2019: World Brackishwater Aquaculture Conference. Journal of Coastal Research, Special Issue No. 86, pp. 21–31. Coconut Creek (Florida), ISSN 0749-0208. Growth, survival and osmoregulation of Indian white shrimp, Penaeus indicus juveniles were assessed in two water types' namely inland saline groundwater (ISGW) and seawater (SW). Raw ISGW is deficient in potassium (K+) and causes poor survival of shrimp. Amended ISGW (Na+/K+ ratio – 44:1; Mg2+/Ca2+ ratio – 1.8:1) of salinities 5, 10, and 15 ppt were artificially prepared by mixing of different salts in freshwater. The SW of salinities 5, 10, 15, and 27 ppt were prepared from oceanic water. Juvenile shrimp (∼0.069 g) were stocked to triplicate 120 L tanks (30 shrimp per tank) filled with amended ISGW and SW of different salinities and reared for 45 days (average water temperature, 26.7±0.1°C). All shrimp survived the experimental duration in SW of 10 ppt and amended ISGW of 10 and 15 ppt. Survival was significantly lower in SW of 5, 15 and 27 ppt (75.5–81.1%), and that in amended ISGW of 5 ppt (91.1%) was similar to other treatments. Final mean body weight of shrimp (1–1.2 g) and other growth parameters was not affected by water types and salinities. Serum osmolality was significantly lower for juveniles in amended ISGW of 5 and 10 ppt over those reared in SW of similar salinity. However, the osmoregulatory capacity of juveniles did not vary between amended ISGW and SW of identical salinities. Iso-osmotic point of shrimp in amended ISGW and SW were 793.8 (26.5 ppt) and 779.2 mOsmol Kg-1 (25.9 ppt) respectively. Tail muscle moisture content was significantly lower for shrimp in amended ISGW of 5 and 10 ppt, though hepatopancreas moisture contents did not vary between treatments. Penaeus indicus juveniles are efficient osmoregulators and exhibit typical euryhaline behaviour with identical growth parameters over a wide range of salinity. Data suggests that amended ISGW of Na+/K+ ratio ∼45:1 is suitable for P. indicus culture and commercial farming of the species is feasible at low and intermediate salinities. [ABSTRACT FROM AUTHOR]

Objective  Patent ductus arteriosus (PDA) is an important clinical problem associated with mortality and serious morbidities. It is thought that serum osmolality may affect ductal patency. We aimed to investigate the importance of serum osmolality related to ductal patency in preterm infants. Study Design  Our study was conducted between January 2013 and December 2017. Premature infants with birth weight <1,500 g and gestational age <32 weeks were included in the study. Serum osmolality was compared between infants with hemodynamically significant PDA (hsPDA) and non-hsPDA. Results  During the study period, 799 patients were evaluated. Mean serum osmolality levels were higher in the "hsPDA" group (297 ± 10.9 vs. 292 ± 8.3 mOsm/L) (p  = 0.001). The area under the curve for osmolality was 0.582 (p  = 0.0006, 95% confidence interval: 0.541–0.622) at the time of diagnosis for predicting hsPDA, with a cutoff value for osmolality of 300 mOsm/L. Conclusion  Serum osmolality may be recognized as an important contributing factor for ductal patency especially among extremely preterm infants who are most likely to have hsPDA in the early days of life. [ABSTRACT FROM AUTHOR]

Copyright of Wiener Klinische Wochenschrift is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cerebral edema and elevated intracranial pressure (ICP) are common complications of acute brain injury. Hypertonic solutions are routinely used in acute brain injury as effective osmotic agents to lower ICP by increasing the extracellular fluid tonicity. Acute kidney injury in a patient with traumatic brain injury and elevated ICP requiring renal replacement therapy represents a significant therapeutic challenge due to an increased risk of cerebral edema associated with intermittent conventional hemodialysis. Therefore, continuous renal replacement therapy (CRRT) has emerged as the preferred modality of therapy in this patient population. We present our current treatment approach, with demonstrative case vignette illustrations, utilizing hypertonic saline protocols (3% sodium-chloride or, with coexisting severe combined metabolic and respiratory acidosis, with 4.2% sodium-bicarbonate) in conjunction with the CRRT platform, to induce controlled hypernatremia of approximately 155 mEq/L in hemodynamically unstable patients with acute kidney injury and elevated ICP due to acute brain injury. Rationale, mechanism of activation, benefits and potential pitfalls of the therapy are reviewed. The impact of hypertonic citrate solution during regional citrate anticoagulation is specifically discussed. Maintaining plasma hypertonicity in the setting of increased ICP and acute kidney injury could prevent the worsening of ICP during renal replacement therapy by minimizing the osmotic gradient across the blood-brain barrier and maximizing cardiovascular stability. [ABSTRACT FROM AUTHOR]

Chronic dehydration mainly occurs due to insufficient fluid intake over a lengthy period of time, and nursing home residents are thought to be at high risk for chronic dehydration. However, few studies have investigated chronic dehydration, and new diagnostic methods are needed. Therefore, in this study, we aimed to identify risk factors for chronic dehydration by measuring serum osmolality in nursing home residents and also to evaluate whether examining the inferior vena cava (IVC) and determining the IVC collapsibility index (IVC-CI) by ultrasound can be helpful in the diagnosis of chronic dehydration. A total of 108 Japanese nursing home residents aged ≥65 years were recruited. IVC measurement was performed using a portable handheld ultrasound device. Fifteen residents (16.9%) were classified as having chronic dehydration (serum osmolality ≥295 mOsm/kg). Multivariate logistic regression analysis showed that chronic dehydration was associated with dementia (odds ratio (OR), 6.290; 95% confidential interval (CI), 1.270–31.154) and higher BMI (OR, 1.471; 95% CI, 1.105–1.958) but not with IVC or IVC-CI. Cognitive function and body weight of residents should be considered when establishing a strategy for preventing chronic dehydration in nursing homes.

Confusion has persisted for decades in the United States (U.S.) over how much plain water to drink, despite national water intake recommendations which are based on high quality scientific evidence. This editorial summarizes the definition, alignment and coordination of evidence that informs the current U.S. adequate intake (AI) recommendations for water. It highlights gaps in the evidence that perpetuate confusion and opportunity to address the gaps through strategic planning.