Association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction: analysis of the MIMIC- IV database.

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.

Unmeasured Osmoles: The Hidden Solutes Obscuring a Hyponatremia Evaluation.

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.

Heart failure related fatigue: An exploratory analysis of serum osmolality from the national health and nutrition examination survey.

BACKGROUND: 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. OBJECTIVES: Describe the relationship between serum osmolality and fatigue in adults with HF. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Effects of Total Parenteral Nutrition on Serum Osmolality and Patent Ductus Arteriosus.

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.

Association between serum osmolality and risk of in-hospital mortality in patients with intracerebral hemorrhage.

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.

The Relationship between the Ratio of Urine Osmolality to Serum Osmolality and Neurological Outcomes in Out-of-hospital Cardiac Arrest Patients.

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.

Association between serum osmolality and 28-day all-cause mortality in patients with heart failure and reduced ejection fraction: a retrospective cohort study from the MIMIC-IV database.

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.

The prevalence of chronic dehydration and associated with cardiometabolic risks among agriculture and aquaculture workers.

Background: Chronic 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. Methods: We 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. Results: A 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 < 0.001), 10-year stroke risk prediction (p < 0.001), and an unhealthy lifestyle (p < 0.001). Conclusion: The prevalence of chronic dehydration was higher in Taiwanese agriculture and aquaculture workers, which was significantly associated with cardiometabolic risks and unhealthy lifestyles.

Acute Ethanol Intoxication: Αn Overlooked Cause of High Anion Gap Metabolic Acidosis With a Marked Increase in Serum Osmolal Gap.

Measurement of serum osmolal gap is a useful tool in suspected toxic alcohol ingestion. Normal levels of osmolal gap are typically <10 mOsm/kg). Osmolal gap >20 mOsm/kg is usually caused by ingestion of methanol, ethylene glycol, isopropanol, propylene glycol, diethylene glycol, or organic solvents such as acetone but rarely of ethanol alone. Herein, we describe the case of a severe ethanol intoxication presenting with a marked increase in the osmolal gap. An 18-year-old male was referred to the emergency department of our hospital, in a comatose state, following binge drinking. blood gas analysis revealed a high anion gap metabolic acidosis. In addition, it was found an extremely elevated osmolal gap of 91 mOsm/kg. The increment of the osmolal gap and the high anion gap acidosis could not be attributed to methanol/ethylene glycol intoxication, alcoholic ketoacidosis, or other cause of acidosis. The calculated osmolal concentration of ethanol was 91 mOsm/kg (osmolal concentration of ethanol is equal to the serum ethanol levels (mg/dL) divided by 3.7). Thus, the increase in the osmolal gap was a result of ethanol intoxication solely. Acute, isolated, ethanol intoxication may be a rare cause of a marked increase of osmolal gap with high anion gap metabolic acidosis. Clinicians should be alerted to the possibility of acute ethanol intoxication in a patient presenting with high anion gap metabolic acidosis and an extremely elevated osmolal gap. Toxicologic screen tests should be performed to identify the aetiology of the gap rise and proper therapy should be administered.

The effect of Ramadan fasting on serum osmolality in diabetic patients.

OBJECTIVE: To observe the changes of osmolarity levels due to fasting in Ramadan among type 2 diabetic patients. METHODS: 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). CONCLUSIONS: There was no biochemical sign of dehydration with Ramadan fasting in type 2 diabetes mellitus patients. Clinical Trial Number: [NCT04392570] Link: https://clinicaltrials.gov/.

[Treatment of acute diabetic metabolic crises in adults (Update 2023) : Hyperglycemic hyperosmolar state and ketoacidotic metabolic disorder]. / Therapie der akuten diabetischen Stoffwechselentgleisungen bei Erwachsenen (Update 2023) : Hyperglykämisch-hyperosmolare und ketoazidotische Stoffwechselentgleisung.

Diabetic ketoacidosis (DKA) and the hyperglycemic hyperosmolar state (HHS) represent potentially life-threatening situations in adults. Therefore, rapid comprehensive diagnostic and therapeutic measures with close monitoring of vital and laboratory parameters are required. The treatment of DKA and HHS is essentially the same and replacement of the mostly substantial fluid deficit with several liters of a physiological crystalloid solution is the first and most important step. Serum potassium concentrations need to be carefully monitored to guide its substitution. Regular insulin or rapid acting insulin analogues can be initially administered as an i.v. bolus followed by continuous infusion. Insulin should be switched to subcutaneous injections only after correction of the acidosis and stable glucose concentrations within an acceptable range.

Water intake, hydration status and 2-year changes in cognitive performance: a prospective cohort study.

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 (ß: - 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.

Ex vivo LPS-stimulated cytokine production is associated with hydration status in community-dwelling middle-to-older-aged adults.

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.

Association of serum osmolality with all-cause and cardiovascular mortality in US adults: A prospective cohort study.

BACKGROUND AND AIMS: 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. METHODS AND RESULTS: 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. CONCLUSION: 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 and hyperosmolar states.

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.

Serum and Urine Osmolality as Predictors of Adequate Diuresis in Acute Decompensated Heart Failure: A Prospective Cohort Study.

BACKGROUND: Determination of adequacy of decongestion remains a significant challenge in the management of acute heart failure (AHF). METHODS: This is a prospective single center cohort study of patients (>18 years old) admitted for AHF on intravenous diuretics, with BNP >100 pg/mL or echocardiographic findings of reduced ejection fraction or diastolic dysfunction, and at least 1 clinical sign of volume overload. Patients with eGFR ≤45 mL/min or on dialysis, and with exposure to contrast dye or nephrotoxins were excluded. Serum and spot urine osmolality were obtained in the early morning simultaneously daily for 5 days or until discharge. Receiver operating characteristic curves were used to analyze the optimal cutoffs for the osmolality values in the prediction of heart failure (HF) readmissions Results: Of the total 100 patients, 62% were male and 59% were Black American. The mean age was 64.41 ± 12.53 and 34% had preserved ejection fraction. Patients with 30-day readmission had higher serum osmolality (mOsm/kg) on admission (305 [299-310] vs. 298 [294-303]; p = 0.044) and had higher drop in serum osmolality between admission and discharge (-7.5 [-9.0, -1.25] vs. -1.0 [-4.0, 4.0]; p = 0.044). Serum osmolality on admission of >299 mOsm/kg (sensitivity: 83%, specificity: 61%) and drop in serum osmolality between admission and discharge of >2 mOsm/kg (sensitivity: 83%, specificity: 65%) was associated with 30-day HF readmissions. No patients discharged with urine osmolality more than 500 mOsm/kg had 30-day readmissions, but this was not statistically significant, p = 0.334. CONCLUSION: Measurement of serum osmolality and urine osmolality may have some utility in AHF, but interpretation should consider baseline values and dynamic changes to account for individual differences in sodium and water handling.

Association Between Serum Osmolality and Acute Kidney Injury in Critically Ill Patients: A Retrospective Cohort Study.

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 <285 mmol/L. Multivariate logistic regression indicated that high serum osmolality was independently associated with increased development of AKI with OR = 1.198 (95% CL = 1.199-1.479, P < 0.001) and low serum osmolality was also independently associated with increased development of AKI with OR = 1.332 (95% CL = 1.199-1.479, P < 0.001), compared with normal serum osmolality, respectively. Conclusions: In critically ill patients, early high serum osmolality and low serum osmolality were both independently associated with an increased risk of development of AKI.

Chronic Dehydration in Nursing Home Residents.

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.

Water Researchers Do Not Have a Strategic Plan for Gathering Evidence to Inform Water Intake Recommendations to Prevent Chronic Disease.

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.

Copeptin Kinetics and Its Relationship to Osmolality During Rehydration for Diabetic Ketoacidosis in Children.

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.