Vasopressin escape and memory impairment in a model of chronic syndrome of inappropriate secretion of antidiuretic hormone in mice.

Recently, chronic hyponatremia, even mild, has shown to be associated with poor quality of life and high mortality. The mechanism by which hyponatremia contributes to those symptoms, however, remains to be elucidated. Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a primary cause of hyponatremia. Appropriate animal models are crucial for investigating the pathophysiology of SIADH. A rat model of SIADH has been generally used and mouse models have been rarely used. In this study, we developed a mouse model of chronic SIADH in which stable and sustained hyponatremia occurred after 3-week continuous infusion of the vasopressin V2 receptor agonist 1-desamino-8-D-arginine vasopressin (dDAVP) and liquid diet feeding to produce chronic water loading. Weight gain in chronic SIADH mice at week 2 and 3 after starting dDAVP injection was similar to that of control mice, suggesting that the animals adapted to chronic hyponatremia and grew up normally. AQP2 expression in the kidney, which reflects the renal action of vasopressin, was decreased in dDAVP-infused water-loaded mice as compared with control mice that received the same dDAVP infusion but were fed pelleted chow. These results suggest that "vasopressin escape" occurred, which is an important process for limiting potentially fatal severe hyponatremia. Behavioral analyses using the contextual and cued fear conditioning test and T-maze test demonstrated cognitive impairment, especially working memory impairment, in chronic SIADH mice, which was partially restored after correcting hyponatremia. Our results suggest that vasopressin escape occurred in chronic SIADH mice and that chronic hyponatremia contributed to their memory impairment.

Altered Mental Status and Hyponatremia After 20 Hours of Amiodarone Therapy.

A 66-year-old woman with no relevant medical history presented at the emergency department with new-onset atrial fibrillation. We initiated intravenous amiodarone therapy. At 20 hours, the patient experienced severe neurologic symptoms, hyponatremia, and syndrome of inappropriate antidiuretic hormone. We discontinued amiodarone, infused saline solution, and restricted the patient's fluid intake. She recovered in 3 days. This case illustrates that amiodarone-induced syndrome of inappropriate antidiuretic hormone with hyponatremia can occur far earlier than expected during acute amiodarone therapy.

Impairment of Neurocognitive Functioning, Motor Performance, and Mood Stability in Hospitalized Patients With Euvolemic Moderate and Profound Hyponatremia.

BACKGROUND: The impact of chronic moderate and profound hyponatremia on neurocognitive performance, motor skills, and mood stability has not been investigated systematically so far, and results regarding mild to moderate hyponatremia are inconsistent. Furthermore, it is not known whether treatment has an effect on outcome in these patients. METHODS: A total of 130 hospitalized patients with confirmed euvolemic hyponatremia (<130 mEq/L) were subjected to a test battery (Mini-Mental State Examination, DemTect, Trail-Making Tests A and B, Beck Depression Inventory, Timed-up-and-go Test) before and after treatment; additionally, 50 normonatremic group-matched patients served as reference group. RESULTS: The scores of all tested domains were significantly worse in the hyponatremia group (median serum sodium [Na+] 122 (119-126) mEq/L) as compared to the reference group (P <0.001), and the odds of obtaining a pathological test result increased markedly with more profound hyponatremic states (odds ratios between 5.0 and 21.8 in the group with Na+ <120 mEq/L compared to reference group). Inversely, treatment led to a significant amelioration of all test results with medium to large effect sizes. Linear regression models revealed the increment of Na+ as an important predictor of test outcome. CONCLUSION: We demonstrate a clear association between lower levels of Na+ beyond mild hyponatremia and impairment of neurocognitive and motor performance as well as mood disorders. Our analysis further suggests a causal role of hyponatremia in this context. However, there are apparent differences between the distinct tested domains warranting further investigations.

Effects of Lower Past-Year Serum Sodium and Hyponatremia on Depression Symptoms and Cognitive Impairments in Patients With Hemodialysis.

The relationship between hyponatremia, depression symptoms, and cognitive impairments in patients receiving hemodialysis treatment remain unclear. This study aimed to examine the impact of past-year average serum sodium levels on current depression symptoms and cognitive impairments in patients receiving hemodialysis, with adjustment for possible confounders. A total of 200 participants were recruited for this study. Depression symptoms and cognitive impairments were assessed using the Patient Health Questionnaire and Perceived Deficits Questionnaire-5, respectively. Additionally, sociodemographic features, physical health, metabolic factors, and substance use information were collected. Significant associations between serum sodium levels, depression symptoms, and cognitive impairments were found after multivariate regression analysis. Furthermore, such differences were observed profoundly in moderate to profound hyponatremia. Our study revealed exclusive relationships between hyponatremia, depression symptoms, and cognitive impairments. As such, programs of cognitive rehabilitation and emotional regulation should be included in the prevention of chronic kidney disease for moderate to profound hyponatremia.

Impact of Resolution of Hyponatremia on Neurocognitive and Motor Performance in Geriatric Patients.

This observational study investigated the impact of hyponatremia resolution on the results of a comprehensive geriatric assessment (CGA) in 150 patients with age ≥70 years and serum sodium <130 mEq/L. The test battery including Barthel index of Activities of Daily Living (ADL) and various tests of neurocognitive function, motor performance and mood stability was applied on admission and at discharge. Changes of individual test results (Δ) were analyzed and normonatremic patients matched for age, gender, and ADL served as reference group. Most CGA test results improved. The improvement was more pronounced in the hyponatremia group with respect to ADL (ΔADL: 14.3 ± 17.1 vs. 9.8 ± 14.7; p = 0.002) and MMSE (ΔMMSE: 1.8 ± 3.0 vs. 0.7 ± 1.9; p = 0.002). Effect sizes were small (i.e., >0.2) in the overall analysis for ΔADL and ΔMMSE and moderate (i.e., >0.5) for ΔMMSE in the euvolemic subgroup. Beneficial effects on ΔADL and ΔMMSE were only observed in the subgroup of patients in which [Na+] was raised by >5 mEq/L and multivariable linear regression analysis confirmed [Na+] increase to be an independent predictor of MMSE improvement. Resolution of hyponatremia has a beneficial impact on the geriatric patients' overall functional status, in particular in euvolemic cases.

The Motoric Types of Delirium and Estimated Blood Loss during Perioperative Period in Orthopedic Elderly Patients.

BACKGROUND: Delirium is a common and serious syndrome in elderly patients. The hypoactive type of delirium is known to have different characteristics, but further studies are needed to define the specificities of these characteristics. Our study aims at finding specific risk factors, especially estimated blood loss during operations of hyper- and hypoactive delirium in orthopedic elderly patients. METHODS: One hundred and seventy-five elderly patients were evaluated using the Confusion Assessment Method (CAM) and the 4th edition text revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Trained psychiatrists interviewed the subjects directly at pre- and postoperative time points. We reviewed medical records after the patients were discharged. RESULTS: Thirty-nine patients (22.3%) were diagnosed with multiple types of delirium, which included 17 hyperactive types (65.9%), 13 hypoactive types (33.3%), and 9 mixed types (23.1%). Although the mean estimated blood loss in patients with either hyper- or hypoactive symptoms was larger than in patients lacking these symptoms, the odds ratio was only significant in patients with hyperactive symptoms. In addition, age, preoperative daily function, and preoperative hyponatremia were found to be risk factors for hyperactive but not hypoactive symptoms. CONCLUSION: Patients with hypoactive symptoms had different risk factors than patients with hyperactive symptoms of delirium. The estimated blood loss, well-known risk factors for delirium, might be risk factors for only hyperactive delirium. The acute precipitating factors seemed to show stronger correlation with the hyperactive type of delirium than with the hypoactive type.

Serum Sodium and Cognition in Older Community-Dwelling Men.

BACKGROUND AND OBJECTIVES: Mild hyponatremia is a common finding in older adults; however, the association of lower serum sodium with cognition in older adults is currently unknown. We determined whether lower normal serum sodium is associated with cognitive impairment and risk of cognitive decline in community-dwelling older men. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Five thousand four hundred thirty-five community-dwelling men aged ≥65 years who participated in Osteoporotic Fractures in Men, a cohort study with a median follow-up for cognitive function of 4.6 years, were included in this analysis. Multivariable logistic regression was used to examine the association between baseline fasting serum sodium levels and the odds of prevalent cognitive impairment (cross-sectional analysis; modified Mini-Mental Status [3MS] score <1.5 SD [<84] below or Trail Making Test Part B time >1.5 SD above the mean [>223 seconds]) and cognitive decline (prospective analysis [n=3611]; decrease in follow-up 3MS score or increase in Trails B time >1.5 SD of the mean score/time change [>9 or >67 seconds]). RESULTS: Participants were aged 74±6 years with a fasting mean serum sodium level of 141±3 mmol/L. Fifteen percent (n=274), 12% (n=225), and 13% (n=242) had prevalent cognitive impairment in tertiles 1, 2, and 3, respectively. After adjustment, lower serum sodium was associated with prevalent cognitive impairment (tertile 1 [126-140 mmol/L] versus tertile 2 [141-142 mmol/L], odds ratio [OR], 1.30; 95% confidence interval [95% CI], 1.06 to 1.61). Fourteen percent (n=159), 10% (n=125), and 13% (n=159) had cognitive decline in tertiles 1, 2, and 3, respectively. Lower serum sodium was also associated with cognitive decline (tertile 1 versus tertile 2, OR, 1.37; 95% CI, 1.06 to 1.77). Tertile 3 (143-153 mmol/L) was additionally associated with cognitive decline. Results were similar in sensitivity analyses according to clinical cut-offs and by quartiles. CONCLUSIONS: In community-dwelling older men, serum sodium between 126-140, and 126-140 or 143-153 mmol/L, are independently associated with prevalent cognitive impairment and cognitive decline, respectively.

Hyponatremia effect in patients with alcohol dependence on their physical and mental health status.

Hyponatremia, i.e. reduction of sodium level in the blood plasma below 135 mmol/L, is one of the most common electrolyte disorders occurring in people addicted to alcohol. Numerous psychopathological symptoms may be significantly associated with its occurrence. Since sodium is one of the main bioelements, which is responsible for proper neuromuscular excitability maintenance and contributes in nerve impulses conduction, sodium balance disorders may be related to a risk to basic life functions. The tested group included 100 alcohol dependent patients (M = 90, F = 10). Sodium was determined using biochemical Indiko Plus analyzer. Analysis of sodium concentration demonstrated that 64% of people with alcohol dependence had low (<135 mmol/L) plasma sodium level, of which: 7% had severe hyponatremia (<120 mmol/L), 13% had moderate hyponatremia (120-130 mmol/L) and 44% had mild hyponatremia (130-135 mmol/L). The analysis showed an occurrence of significant differences in terms of: impulsivity, quality of life, clinical symptoms occurrence, maximum amount of alcohol consumed and general health state. The lower concentration of sodium in blood plasma in alcohol dependent people, the worse psychical and psychological quality of their life.

Chronic Hyponatremia Causes Neurologic and Psychologic Impairments.

Hyponatremia is the most common clinical electrolyte disorder. Once thought to be asymptomatic in response to adaptation by the brain, recent evidence suggests that chronic hyponatremia may be linked to attention deficits, gait disturbances, risk of falls, and cognitive impairments. Such neurologic defects are associated with a reduction in quality of life and may be a significant cause of mortality. However, because underlying diseases such as adrenal insufficiency, heart failure, liver cirrhosis, and cancer may also affect brain function, the contribution of hyponatremia alone to neurologic manifestations and the underlying mechanisms remain unclear. Using a syndrome of inappropriate secretion of antidiuretic hormone rat model, we show here that sustained reduction of serum sodium ion concentration induced gait disturbances; facilitated the extinction of a contextual fear memory; caused cognitive impairment in a novel object recognition test; and impaired long-term potentiation at hippocampal CA3-CA1 synapses. In vivo microdialysis revealed an elevated extracellular glutamate concentration in the hippocampus of chronically hyponatremic rats. A sustained low extracellular sodium ion concentration also decreased glutamate uptake by primary astrocyte cultures, suggesting an underlying mechanism of impaired long-term potentiation. Furthermore, gait and memory performances of corrected hyponatremic rats were equivalent to those of control rats. Thus, these results suggest chronic hyponatremia in humans may cause gait disturbance and cognitive impairment, but these abnormalities are reversible and careful correction of this condition may improve quality of life and reduce mortality.

Hyponatremia and poor cognitive outcome following pediatric brain tumor surgery.

OBJECT: Pediatric intracranial neoplasms are common and cause substantial neurological morbidity. Postoperative hyponatremia is also common and may exacerbate neurological injury. The authors performed an exploratory analysis to evaluate an exposure-response relationship between hyponatremia severity and cognitive function at discharge. METHODS: A retrospective cohort of patients 0-19 years old who underwent a first intracranial neoplasm surgery at a pediatric tertiary care hospital was reviewed. Outcome was assessed by Pediatric Cerebral Performance Category (PCPC) score of 1-6 at hospital discharge. Poor outcome was defined as PCPC score 3-6, corresponding to moderate or worse disability. RESULTS: Of 319 total children, 80 (25%) had poor outcomes. One hundred thirty-seven children (43%) had serum sodium concentrations ≤ 131-135 mEq/L and 39 (12%) had serum sodium concentrations ≤ 130 mEq/L. Lower nadir sodium concentration and longer duration of hyponatremia were significantly associated with worsening PCPC score (p < 0.001). Rapid sodium decreases and more hyponatremic episodes were also significantly associated with worsening PCPC score (p < 0.001). After adjustment for patient factors, tumor characteristics, and measures of sodium disruption, multivariable analysis revealed noncortical tumor locations and lower nadir sodium concentration (adjusted odds ratio 0.86, 95% confidence interval 0.78-0.95) were important independent risk factors for poor cognitive outcome. CONCLUSIONS: Neurocognitive disability and hyponatremia are common in children undergoing surgery for intracranial neoplasms. This study found a significant association between severity of hyponatremia and worsened cognitive outcome, with an apparent exposure-response relationship. These data support the need for careful postoperative monitoring of serum sodium. Further research is needed to determine if prevention and treatment of hyponatremia can improve outcomes in these children.

Mild hyponatremia is associated with functional and cognitive decline in chronic hemodialysis patients.

BACKGROUND: A high incidence and adverse outcomes of cognitive impairment in dialysis patients have recently become recognized. Classical risk factors, uremia, anemia, metabolic disturbances, and hemodynamic instability during dialysis accelerate vascular cognitive impairment. AIMS: To evaluate laboratory factors that influence cognitive function in consecutive chronic hemodialysis (CHD) patients over a 2-year period. METHODS: Between June 2010 and June 2011 we conducted a prospective, single-center trial that evaluated cognitive function in adult chronic hemodialysis (HD) patients. A battery of cognitive function tests was used: modified mini mental state (3MS), trailmaking tests A (trails A) and B (trails B). The 15-item geriatric depression scale (GDS) and the activities of daily living (ADL) test were used, respectively, for assessing symptoms of depression and global functional status. All tests were performed twice at yearly intervals in consecutive HD patients. Global cognitive impairment was defined as a 3MS < 80 and impaired executive function as a Trails A performance time > 75 seconds and Trails B > 180 seconds. RESULTS: 56 chronic HD patients aged 65.00 ± 17.8 years were studied; 57% of them were males. 86% suffered from hypertension (HTN), 40% were diabetics and ~ 1/3 had ischemic heart disease, congestive heart failure (CHF), and dyslipidemia. Average plasma calcium, phosphorus, and PTH were within the recommended range. No features suggestive of malnutrition, severe anemia, inflammation, or inadequate dialysis were detected. 14 patients (24%) had mild chronic hyponatremia (Na ranges 131 - 135 meq/L). Significant disturbances in global cognitive and executive function were detected in the study patients. In 2010, 50% had 3MS < 80, 71% and 91% had severely impaired trails A and B tests (respectively), 54% had symptoms of depression and 50% suffered from impaired ADL. Retesting of the survivors in 2011 revealed increased prevalence of cognitive and functional declines along with worsening depression scoring. Univariate analysis demonstrated significant correlation between cognitive decline and age, female gender, education, poor executive and functional status, inadequate dialysis dose (Kt/V < 1.2, p = 0.023), high plasma phosphorus levels (p > 6 mg/dL, p = 0.034), and hyponatremia (Na < 135 mEq/L, p = 0.001). Multivariate stepwise logistic regression analysis revealed statistically significant associations between hyponatremia and impaired ADL (p = 0.043) and impaired ADL and mortality (p = 0.002). CONCLUSIONS: A high prevalence of global cognitive and executive impairment was detected in our hemodialysis cohort. We found an association between mild chronic hyponatremia and impaired functional status. Whether treatments aimed at modifying hyponatremia could mitigate functional decline or mortality remains to be elucidated.

[Difficulties in the differential diagnosis of hyponatremia presenting with severe neuropsychiatric symptoms]. / Súlyos neuropszichiátriai tünetekkel járó hyponatraemia differenciáldiagnosztikai nehézségei.

Hyponatremia is the most frequent eletrolyte imbalance in hospitalized geriatric patient. The accompanying signs and symptoms can run a wide range and, therefore, these patients are usually admitted to various departments, i.e. neurology and/or traumatology first. Directed laboratory investigations demonstrate severe hyponatremia. Differential diagnosis can be very difficult and complex in the clinical settings. Firstly, spurious forms of hyponatremia have to be excluded, then the underlying cause should elucidated based on the patients hydration status and serum osmolarity. Hyponatremia can be divided into hyper-, hypo- and normovolemic forms. Moreover, it can be further classified as hypo-, iso- and hyperosmolar hyponatremias. The differentiation between renal and extrarenal salt wasting forms is hinged on the urine sodium concentration. Syndrome of inappropriate antidiuretic hormone secretion is the most common cause of normovolemic, hypoosmolar forms (named also as Schwartz-Bartter syndrome). The authors aimed to shed light on the often insurmountable difficulties of the diagnosis, differential diagnosis and appropriate treatment of this very frequent electrolyte imbalance by presenting a clinical case report. Their purported aim reflects upon the wide array of ethiopathogenesis of hyponatremia: various endocrine, renal diseases, inappropriateness of antidiuretic hormone secretion as well as the role of different medications (e.g. diuretics). This fine-tuned and intricate physiology of sodium metabolism could fortuitously be overturned by these mechanisms.

Differential impact of hyponatremia and hepatic encephalopathy on health-related quality of life and brain metabolite abnormalities in cirrhosis.

BACKGROUND & AIMS: Hyponatremia (HN) and hepatic encephalopathy (HE) together can impair health-related quality of life (HRQOL) and cognition in cirrhosis. We aimed at studying the effect of hyponatremia on cognition, HRQOL, and brain MR spectroscopy (MRS) independent of HE. METHODS: Four cirrhotic groups (no HE/HN, HE alone, HN alone (sodium <130 mEq/L), HE+HN) underwent cognitive testing, HRQOL using Sickness Impact Profile (SIP: higher score is worse; has psychosocial and physical sub-scores) and brain MRS (myoinositol (mI) and glutamate+glutamine (Glx)), which were compared across groups. A subset underwent HRQOL testing before/after diuretic withdrawal. RESULTS: 82 cirrhotics (30 no HE/HN, 25 HE, 17 HE+HN, and 10 HN, MELD 12, 63% hepatitis C) were included. Cirrhotics with HN alone and without HE/HN had better cognition compared to HE groups (median abnormal tests no-HE/HN: 3, HN: 3.5, HE: 6.5, HE+HN: 7, p=0.008). Despite better cognition, HN only patients had worse HRQOL in total and psychosocial SIP while both HN groups (with/without HE) had a significantly worse physical SIP (p<0.0001, all comparisons). Brain MRS showed the lowest Glx in HN and the highest in HE groups (p<0.02). mI levels were comparably decreased in the three affected (HE, HE+HN, and HN) groups compared to no HE/HN and were associated with poor HRQOL. Six HE+HN cirrhotics underwent diuretic withdrawal which improved serum sodium and total/psychosocial SIP scores. CONCLUSIONS: Hyponatremic cirrhotics without HE have poor HRQOL despite better cognition than those with concomitant HE. Glx levels were lowest in HN without HE but mI was similar across affected groups. HRQOL improved after diuretic withdrawal. Hyponatremia has a complex, non-linear relationship with brain Glx and mI, cognition and HRQOL.

Serum natremia affects health-related quality of life in patients with liver cirrhosis: a prospective, single centre study.

INTRODUCTION: Hyponatremia is associated with high mortality and predicts hepatic encephalopathy but its effect on health-related quality of life remains to be established. MATERIAL AND METHODS: In this study we prospectively analyzed the relationship between hyponatremia, clinical features and quality of life in a cohort of 116 patients with cirrhosis. Chronic Liver Disease Questionnaire and Medical Outcomes Study 36- Item Short Form Health Survey were performed to assess quality of life. Evaluation of hepatic encephalopathy included West-Haven criteria, Psychometric Hepatic Encephalopathy Score and Critical Flicker Frequency analysis. Severity of liver disease was assessed with Child-Pugh score and MELD. Univariate and multivariate analysis were implemented to evaluate the influence of analyzed factors on quality of life. RESULTS: Multivariate analysis has identified serum natremia, Psychometric Hepatic Encephalopathy Score, Critical Flicker Frequency and severity of liver disease measured with MELD and Child-Pugh score as independent factors affecting quality of life in patients with cirrhosis. West Heaven criteria failed to show the relationship with quality of life in analyzed subjects. Serum kalemia showed correlation with neither quality of life, hepatic encephalopathy nor severity of the disease. CONCLUSION: In patients with cirrhosis serum natremia along with severity of liver disease and hepatic encephalopathy exerts a significant effect on patients' quality of life.

Falls and cognitive dysfunction impair health-related quality of life in patients with cirrhosis.

INTRODUCTION: Falls are frequent in patients with cirrhosis and cognitive dysfunction and can deteriorate health-related quality of life (HRQoL). OBJECTIVE: To evaluate the relationship between previous falls and HRQoL in patients with cirrhosis. METHODS: We measured HRQoL in 118 outpatients with cirrhosis using the Medical Outcomes Study Short Form (SF-36) questionnaire, grouping items into the Physical Component Score (PCS) and the Mental Component Score (MCS). The incidence of accidental falls in the 12 months before the study was assessed using a specific questionnaire. The Psychometric Hepatic Encephalopathy Score (PHES) was administered to assess cognitive dysfunction. We considered cognitive dysfunction if PHES was less than -4. HRQoL was compared between patients with falls and patients without falls. RESULTS: HRQoL was lower in patients with previous falls than in patients without falls (P<0.05 in all domains of SF-36). In the multivariate analysis, the only independent factors that affected the HRQoL in the PCS were (B coefficient, 95% confidence interval) cognitive dysfunction (6.5, 3.2-9.7, P<0.001), previous variceal bleeding (3.9, 0.4-7.3, P=0.02), anemia (3.2, 0.07-6.4, P=0.049), and hyponatremia (9.3, 1.07-17.5, P<0.02). Multivariate analysis for MCS showed the independent factors for worse HRQoL were female sex (12.2, 6.9-17.5, P<0.001) and previous falls (10.3, 4.0-16.5, P=0.001). CONCLUSION: Falls and cognitive dysfunction are independent factors associated with impaired HRQoL in patients with cirrhosis. Strategies addressed to improve HRQoL in these patients should consider the treatment of cognitive dysfunction and prevention of falls.

Hyponatremia in geriatric inhospital patients: effects on results of a comprehensive geriatric assessment.

OBJECTIVES: To study whether geriatric patients with mild-to-moderate hyponatremia (≤131 mmol/l) reveal different outcomes in structured tests for functional and cognitive impairments, depression and malnutrition compared to normonatremic patients. DESIGN: Single-center, retrospective case control study. SETTING: The study was conducted in a Geriatric Evaluation and Management Unit of a Department for Geriatrics and Internal Medicine. METHODS AND PARTICIPANTS: We included 2,880 elderly patients (75.6% female, mean age 78.6 ± 6.98 years), consecutively admitted to the GEMU primarily or from another hospital or emergency department. Results were compared between a group of 129 patients with mild-to-moderate hyponatremia (118-131 mmol/l) and an age- and sex-matched control group of 129 patients with normal serum sodium values (>135 mmol/l). To assess functional and cognitive status, depression and malnutrition we used standardized tests of a geriatric assessment. RESULTS: 16.7% (n = 477) of the total 2,880 patients were hyponatremic (≤135 mmol/l), 4.5% (n = 129) revealed moderate hyponatremia. Compared to the control group, these patients had significantly worse results in all tests of the Geriatric Assessment, including Activities of Daily Living, Mini Mental State Examination, Clock Completion Test, Geriatric Depression Score, Tinetti Mobility Test and the Timed Up&Go Test and the Mini Nutritional Assessment. Comorbidities were assessed by the Charlson Comorbidity Index and the Cumulative Illness Rating Scale with no significant difference between the two groups. The hyponatremic patients received significantly more medications than the normonatremic control group, but we could not find a significant difference with respect to the use of a distinct single drug therapy. CONCLUSION: We were able to demonstrate that geriatric patients with mild-to-moderate hyponatremia revealed a significantly worse outcome in all standardized tests of the geriatric assessment compared to a normonatremic control group. Serum sodium levels should therefore be considered when interpreting common tests of geriatric assessment.