Prevalence of hyponatremia on geriatric wards compared to other settings over four decades: a systematic review

Prevention of Chronic Kidney Disease and Its Complications in Older Adults

In an era marked by a global demographic shift towards an aging society, there is a heightened prevalence of chronic kidney disease (CKD) among older adults. The burden of CKD spans from kidney-related complications to impacting psychological well-being, giving rise to depressive symptoms and caregiver burnout. This article delves into CKD prevention strategies within the context of aging, contributing to the discourse by exploring its multifaceted aspects. The prevention of CKD in the older adults necessitates a comprehensive approach. Primary prevention is centered on the modification of risk factors, acknowledging the intricate interplay of various comorbidities. Secondary prevention focuses on early CKD identification. Tertiary prevention aims to address factors contributing to CKD progression and complications, emphasizing the importance of timely interventions. This comprehensive strategy aims to enhance the quality of life for individuals affected by CKD, decelerating the deterioration of functional status. By addressing CKD at multiple levels, this approach seeks to effectively and compassionately care for the aging population.

Clinical Factors Affecting Daily Dosage of Desmopressin Orally Disintegrating Tablets in Arginine Vasopressin Deficiency

CONTEXT

Desmopressin orally disintegrating tablets (ODTs) are widely used to treat arginine vasopressin deficiency (AVP-D). However, limited information is available on the dosage regimen; the dosage for each patient is selected based on their response to the initiation dose.

OBJECTIVE

To investigate the relationships between clinical characteristics and the daily dose of ODTs and to identify factors that affect ODT dosages.

METHODS

This retrospective study included 209 adult patients with AVP-D. Patients were administered ODTs sublingually and instructed to restrict eating and drinking for 30 minutes after taking ODTs using a patient leaflet. ODT dose titration was conducted during hospitalization with close monitoring of urine output, body weight, and serum sodium levels. Multivariable linear regression models were applied to identify clinical factors associated with the daily dose of ODTs at discharge. We also evaluated the dosage at 1 year in 134 patients who were followed up in our hospital.

RESULTS

The median daily dose of ODTs at discharge was 90 µg (IQR 60-120 µg). Multivariable linear regression models identified sex, age, and estimated creatinine clearance (eCCr) as significant factors associated with the daily dose of ODTs, with eCCr having the strongest effect. After excluding patients recovering from AVP-D, 71% of those followed up at our hospital took the same daily dose at 1 year after discharge.

CONCLUSION

To achieve the safe and stable treatment of AVP-D, the daily dose of ODT needs to be selected based on a patient's sex, age, and eCCr under appropriate sublingual administration by patient education.

A step-by-step guide for the diagnosis and management of hyponatraemia in patients with stroke

Hyponatraemia is common in patients with stroke and associated with adverse outcomes and increased mortality risk. The present review presents the underlying causes and provides a thorough algorithm for the diagnosis and management of hyponatraemia in stroke patients. Concomitant diseases and therapies, such as diabetes, chronic kidney disease and heart failure, along with diuretics, antidepressants and proton pump inhibitors are the most common causes of hyponatraemia in community. In the setting of acute stroke, the emergence of hyponatraemia might be attributed to the administration of hypotonic solutions and drugs (ie. mannitol and antiepileptics), poor solute intake, infections, as well as stroke-related conditions or complications, such as the syndrome of inappropriate secretion of antidiuretic hormone, cerebral salt wasting syndrome and secondary adrenal insufficiency. Diagnostically, the initial step is to differentiate hypotonic from non-hypotonic hyponatraemia, usually caused by hyperglycaemia or recent mannitol administration in patients with stroke. Determining urine osmolality, urine sodium level and volume status are the following steps in the differentiation of hypotonic hyponatraemia. Of note, specific parameters, such as fractional uric acid and urea excretion, along with plasma copeptin concentration, may further improve the diagnostic yield. Therapeutic options are based on the duration and symptoms of hyponatremia. In the case of acute or symptomatic hyponatraemia, hypertonic saline administration is recommended. Hypovolaemic chronic hyponatremia is treated with isotonic solution administration. Although fluid restriction remains the first-line treatment for the rest forms of chronic hyponatraemia, therapies increasing renal free water excretion may be necessary. Loop diuretics and urea serve this purpose in patients with stroke, whereas sodium-glucose transport protein-2 inhibitors appear to be a promising therapy. Nevertheless, it is yet unclear whether the appropriate restoration of sodium level improves outcomes in such patients. Randomized trials designed to compare therapeutic strategies in managing hyponatraemia in patients with stroke are required.

Hyponatremia in the emergency department

Hyponatremia, defined as a serum sodium <135 mmol/L, is frequently encountered in patients presenting to the emergency department. Symptoms are often unspecific and include a recent history of falls, weakness and vertigo. Common causes of hyponatremia include diuretics, heart failure as well as Syndrome of Inappropriate Antidiuresis (SIAD) and correct diagnosis can be challenging. Emergency treatment of hyponatremia should be guided by presence of symptoms and focus on distinguishing between acute and chronic hyponatremia.

Elderly with refractory chronic severe hyponatremia and anesthesia management dilemma: a case report with literature review

Hyponatremia is a common electrolyte disorder, especially in the frail elderly population. With the increasing number of surgeries in the aging population, hyponatremia is frequently encountered by anesthesiologists and surgeons. Unfortunately, management of hyponatremia is often complex in the elderly population as it is often multifactorial, and they are physiologically susceptible. While it is well known that preoperative hyponatremia is associated with increased perioperative morbidity and mortality, a lack of recommendations or guidelines adds to the dilemma in managing such cases. The most common cause of chronic hyponatremia in the elderly is the syndrome of inappropriate antidiuretic hormone (SIADH), which can be resistant to conventional treatment. On the other hand, paraneoplastic SIADH leading to hyponatremia is rare, and surgery may be the only option available for its correction. We present a case of a 78- years-gentleman to highlight such a dilemma. He was diagnosed with renal cell carcinoma and had chronic refractory severe hyponatremia despite treatment with fluid restriction, low dose hydrocortisone, tolvaptan, and 3% sodium chloride.

Restoration of dysnatremia and acute kidney injury benefits outcomes of acute geriatric inpatients

Dysnatremia and dyskalemia are common problems in acutely hospitalized elderly patients. These disorders are associated with an increased risk of mortality and functional complications that often occur concomitantly with acute kidney injury in addition to multiple comorbidities. In a single-center prospective observational study, we recruited 401 acute geriatric inpatients. In-hospital outcomes included all-cause mortality, length of stay, and changes in functional status as determined by the Activities of Daily Living (ADL) scale, Eastern Cooperative Oncology Group (ECOG) performance, and Clinical Frailty Scale (CFS). The prevalence of dysnatremia alone, dyskalemia alone, and dysnatremia plus dyskalemia during initial hospitalization were 28.4%, 14.7% and 32.4%, respectively. Patients with electrolyte imbalance exhibited higher mortality rates and longer hospital stays than those without electrolyte imbalance. Those with initial dysnatremia, or dysnatremia plus dyskalemia were associated with worse ADL scores, ECOG performance and CFS scores at discharge. Subgroup analyses showed that resolution of dysnatremia was related to reduced mortality risk and improved CFS score, whereas recovery of renal function was associated with decreased mortality and better ECOG and CFS ratings. Our data suggest that restoration of initial dysnatremia and acute kidney injury during acute geriatric care may benefit in-hospital survival and functional status at discharge.

Preoperative hyponatremia predicts complications in older patients undergoing digestive tract surgery: a propensity score matching analysis

Aim

This study aimed to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Findings

Preoperative hyponatremia was associated with an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery. Preoperative hyponatremia was also correlated with a higher risk of postoperative infectious complications.

Message

Preoperative hyponatremia can predict the development of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Purpose

Whether preoperative hyponatremia increases the risk of postoperative complications in older patients undergoing digestive tract surgery remains unclear. The purpose of the study was to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Methods

This was a propensity score-matched, retrospective cohort study. We recruited older patients (≥ 65 years of age) who underwent digestive tract surgery in our institution. The propensity score matching (PSM; 1:2) was used to balance a range of covariates between patients with preoperative hyponatremia (serum sodium [Na⁺] levels < 135 mmol/L) and those with normal [Na⁺] levels (135–145 mmol/L). The primary outcome was the occurrence of life-threatening postoperative complications and mortality (i.e., Clavien–Dindo grade IV and V [CD IV and V] complications) during hospital stay. The relationship between preoperative hyponatremia and the development of CD IV and V complications was identified with logistic regression analysis.

Results

A total of 1076 patients were analyzed (mean age 73.9 years; 421 female [39.1%]). Preoperative hyponatremia was identified in 122 patients. After matching, 312 patients were included in the analyses (104 patients with preoperative hyponatremia and 208 patients with normal [Na⁺] levels; mean age, 76.3 years; 130 female [41.7%]). When compared with normal [Na⁺] levels, preoperative hyponatremia was associated with an increased risk of CD IV and V complications (odds ratio [OR] 2.082, 95% confidential interval [CI] 1.041–4.164, P = 0.038). Preoperative hyponatremia was also significantly associated with a higher risk of postoperative infectious complications (OR 2.158, 95% CI 1.138–4.091, P = 0.018).

Conclusion

Preoperative hyponatremia can predict an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Potential Use of Pharmacogenetics to Reduce Drug-Induced Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

Syndrome of inappropriate antidiuretic hormone (SIADH) is a common cause of hyponatremia, and many cases represent adverse reactions to drugs that alter ion channel conductance within the peptidergic nerve terminals of the posterior pituitary. The frequency of drug-induced SIADH increases with age; as many as 20% of patients residing in nursing homes have serum sodium levels below 135 mEq/L. Mild hyponatremia is associated with cognitive changes, gait instability, and falls. Severe hyponatremia is associated with cerebral edema, seizures, permanent disability, and/or death. Although pharmacogenetic tests are now being deployed for some drugs capable of causing SIADH (e.g., antidepressants, antipsychotics, and opioid analgesics), the implementation of these tests has been based upon the prior known association of these drugs with other serious adverse drug reactions (e.g., electrocardiographic abnormalities). Work is needed in large observational cohorts to quantify the strength of association between pharmacogene variants and drug-induced SIADH so that decision support can be developed to identify patients at high risk.

Increased Mortality in Elderly Patients Admitted with Hyponatremia: A Prospective Cohort Study

Hyponatremia is the most common electrolyte disorder, commonly affecting older hospitalized individuals; however, the literature is not clear regarding its effect on mortality. The aim of this 2-year observational prospective cohort study was to evaluate the mortality and re-admission rates, the clinical and laboratory characteristics and the causes of hyponatremia in patients older than 65 years admitted with a corrected serum sodium of 130 mEq/L or less in an internal medicine ward of a tertiary Greek university hospital. During the observation period, 138 patients (mean age 80.5 years, 36.2% male) fulfilled the inclusion criteria and were prospectively followed for 1 year after admission. Symptoms of hyponatremia were present in 59.4% of patients. Hypovolemia was the main sole cause of hyponatremia, but in about one third of patients, hyponatremia was multifactorial. Only a low proportion of patients (12.3%) fulfilled the criteria of the syndrome of inappropriate antidiuresis (SIAD) at admission according to the current guidelines. The re-admission rates at 3- and 12-months following discharge was 34.2% and 51.8%, respectively. Mortality during hospitalization was 17.4% and was higher compared to non-hyponatremic admitted older patients, while the total mortality at 1 year after admission was 28.3%, indicating that hyponatremia at admission is a marker of significant mortality during and after hospitalization in elderly patients.

Prescription Habits Related to Chronic Pathologies of Elderly People in Primary Care in the Western Part of Romania: Current Practices, International Recommendations, and Future Perspectives Regarding the Overuse and Misuse of Medicines

The European Commission’s 2019 report regarding the state of health profiles highlighted the fact that Romania is among the countries with the lowest life expectancy in the European Union. Therefore, the objectives of the present study were to assess the current prescription habits of general physicians in Romania related to medicines taken by the elderly population for chronic conditions in both urban and rural setting and to discuss/compare these practices with the current international recommendations for the elderly (American—Beers 2019 criteria and European—STOPP/START v.2, 2015 criteria). A total of 2790 electronic prescriptions for chronic pathologies collected from 18 community pharmacies in the western part of Romania (urban and rural zones) were included. All medicines had been prescribed by general physicians. We identified the following situations of medicine overuse: 15% of the analyzed prescriptions involved the use of nonsteroidal anti-inflammatory drugs (NSAIDs) for >2 weeks, 12% involved the use of a proton-pump inhibitor (PPI) for >8 weeks, theophylline was the bronchodilator used as a monotherapy in 3.17% of chronic obstructive pulmonary disease cases, and zopiclone was the hypnotic drug of choice for 2.31% of cases. Regarding the misuse of medicines, 2.33% of analyzed prescriptions contained an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II receptor blocker (ARB) for patients with renal failure in addition to vitamin K antagonists (AVKs) and NSAIDs in 0.43% of cases. Prescriptions for COX2 NSAIDs for periods longer than 2 weeks for patients with cardiovascular disorders accounted for 1.33% of prescriptions, and trihexyphenidyl was used as a monotherapy for patients with Parkinson’s disease in 0.18% of cases. From the included medical prescriptions, 32.40% (the major percent of 2383 prescriptions) had two potentially inappropriate medications (PIMs). Rural zones were found to be risk factor for PIMs. Decreasing the chronic prescription of NSAIDs and PPIs, discontinuing the use of hypnotic drugs, and avoiding potentially harmful drug–drug associations will have long term beneficial effects for Romanian elderly patients.

Awareness of the use of hyponatraemia-inducing medications in older adults with hyponatraemia: a study of their prevalent use and association with recurrent symptomatic or severe hyponatraemia

BACKGROUND

Cautious use or avoidance of hyponatraemia-inducing medications (HIMs) is recommended in older patients with hyponatraemia.

OBJECTIVE

To evaluate the use of HIMs after treatment for symptomatic or severe hyponatraemia and to investigate the impact of HIMs on the recurrence of symptomatic or severe hyponatraemia in older patients.

DESIGN AND SETTINGS

A cross-sectional and nested case-control study using data obtained from national insurance claims databases.

METHODS

The rate of prescribing HIMs during the 3 months before and after the established index date was analysed in a cross-sectional analysis. Multivariable logistic regression was performed to investigate the association between HIM use and recurrence of symptomatic or severe hyponatraemia after adjusting for covariates in a case-control study.

RESULTS

The cross-sectional study included 1,072 patients treated for symptomatic or severe hyponatraemia. The proportion of patients prescribed any HIMs after hyponatraemia treatment decreased from 76.9 to 70.1%. The prescription rates significantly decreased for thiazide diuretics (from 41.9 to 20.8%) and desmopressin (from 8.6 to 4.0%), but the proportion of patients prescribed antipsychotics increased from 9.2 to 17.1%. Of 32,717 patients diagnosed with hyponatraemia, 913 (2.8%) showed recurrent hyponatraemia. After adjusting for comorbid conditions, the use of any HIMs including proton pump inhibitors [adjusted odds ratio (aOR) 1.34, 95% confidence interval (CI) 1.15-1.57] and two or more HIMs (aOR 1.48, 95% CI 1.22-1.78) especially in combination with thiazide diuretics increased the likelihood of severe hyponatraemia recurrence.

CONCLUSIONS

Prevalent use of HIMs after treatment for symptomatic or severe hyponatraemia and multiple HIM use increase the risk of recurrent hyponatraemia in geriatric patients.

Do the etiology of hyponatremia and serum sodium levels affect the length of hospital stay in geriatric patients with hyponatremia?

Background

Hyponatremia can lead to a prolonged hospital stay and increased morbidity and mortality rates in geriatric patients. This study aimed to evaluate the effects of hyponatremia etiology and serum sodium (Na) levels on hospitalisation time in geriatric patients hospitalised due to hyponatremia.

Methods

The demographic characteristics, laboratory data, etiology of hyponatremia, and length of hospital stay were retrospectively recorded for 132 patients over 65 years of age who were hospitalised for hyponatremia.

Results

Of the 132 patients, 90 were female (68.2%), and 42 were male (31.8%). The serum Na levels of 66 (50%) patients were <120 mmol/L, those of 64 (48.5%) patients were 120-129 mmol/L, and those of two (1.5%) patients were >130 mmol/L. One hundred nine (82.6%) patients had hypoosmolar hyponatremia, 14 (10.6%) patients had isoosmolar hyponatremia, and nine (6.8%) patients had hyperosmolar hyponatremia. Also, 19.7% of the patients were hypovolemic, 37.9% were euvolemic, and 42.4% were hypervolemic. Hyponatremia etiology was congestive heart failure in 38 (28.8%) patients, syndrome of inappropriate antidiuretic hormone in 29 (22.0%) patients, gastrointestinal fluid loss in 24 (18.2%) patients, renal pathologies in 20 (15.2%) patients, the presence of drugs in 20 (15.2%) patients, and hypocortisolemia in one (0.8%) patient. The mean length of hospital stay for the patients was five (1-60) days. There was no statistically significant difference between the lengths of hospital stay based on hyponatremia etiology and serum Na levels (p=0.861 and p=0.076). It was observed that the lengths of stay for patients who developed hyponatremia during their hospitalisation in various clinics were longer than those for patients who presented to the emergency department (p<0.001).

Conclusions

In this study, it was determined that the length of hospital stay did not change with the etiology of hyponatremia and serum Na level at the time of admission, but patients who developed hyponatremia during their hospitalisation had longer hospitalisation times.

Assocıatıons between mıld hyponatremıa and gerıatrıc syndromes ın outpatıent settıngs

PURPOSE

The impact of mild hyponatremia on geriatric syndromes is not clear. Our aim was to determine associations between mild hyponatremia and results of comprehensive geriatric assessment tools in outpatient settings.

METHODS

We reviewed medical records of 1255 consecutive outpatient elderly subjects and compared results of comprehensive geriatric assessment measures among patients with mild hyponatremia (serum Na⁺ 130-135 mEq/L) versus normonatremia (serum Na⁺ 136-145 mEq/L). The comprehensive geriatric assessment measures included the Basic and Instrumental Activities of Daily Living, Mini Mental State Examination, Geriatric Depression Score, Tinetti Mobility Test, the Timed Up&Go Test, the Mini Nutritional Assessment, the handgrip test, the Insomnia Severity Index, polypharmacy, recurrent falls, urinary incontinence, orthostatic hypotension, and nocturia.

RESULTS

Of the 1255 patients, 855 were female (68.1%), and the mean age was 73.7 ± 8.3 years. Mild hyponatremia was detected in 108 patients (8.6%). The median serum sodium was 140.5 [interquartile range (IQR) 138.4-141.8] versus 133.8 [IQR, 132.3-134.2] in normonatremia and mild hyponatremia groups, respectively (p < 0.001). The only significant difference for comorbidities between normonatremia and mild hyponatremia groups was the frequency of hypertension (66.9% versus 76.7%, respectively (p = 0.041). None of the comprehensive geriatric assessment tools conferred a significant association with mild hyponatremia. Of the 1061 subjects with available survival data, 96 (9.0%) deceased within 3-4 years of follow-up (p = 0.742). Hyponatremia as an independent variable did not have a significant effect on mortality in univariate logistic regression analysis (OR 1.13, 95% CI 0.55-2.33, p = 0.742).

CONCLUSION

Mild hyponatremia does not apparently affect results of geriatric assessments significantly. Whether particular causes of hyponatremia may have different impacts should be tested in further studies.

Natremia and liver transplantation: The right amount of salt for a good recipe

An adequate balance between electrolytes and clear water is of paramount importance to maintaining physiologic homeostasis. Natremia imbalance and, in particular, hyponatremia is the most frequent electrolyte abnormality observed in hospitalized subjects, involving approximately one-fourth of them. Pathological changes occurring during liver cirrhosis predispose patients to an increased risk of sodium imbalance, and hypervolemic hyponatremia has been reported in nearly 50% of subjects with severe liver disease and ascites. Splanchnic vasodilatation, portal-systemic collaterals’ opening and increased excretion of vasoactive modulators are all factors impairing clear water handling during liver cirrhosis. Of concern, sodium imbalance has been consistently reported to be associated with increased risk of complications and reduced survival in liver disease patients. In the last decades clinical interest in sodium levels has been also extended in the field of liver transplantation. Evidence that [Na⁺] in blood is an independent risk factor for in-list mortality led to the incorporation of sodium value in prognostic scores employed for transplant priority, such as model for end-stage liver disease-Na and UKELD. On the other hand, severe hyponatremic cirrhotic patients are frequently delisted by transplant centers due to the elevated risk of mortality after grafting. In this review, we describe in detail the relationship between sodium imbalance and liver cirrhosis, focusing on its impact on peritransplant phases. The possible therapeutic approaches, in order to improve transplant outcome, are also discussed. 

Serum electrolytes disorder and its associated factors among adults admitted with metabolic syndrome in Jimma Medical Center, South West Ethiopia: Facility based crossectional study

Background

Electrolytes play an important role in controlling acid base balance, blood clotting, and body fluid and muscle contractions. Serum electrolytes concentrations are most commonly used tests for assessment of a patient’s clinical conditions, and are associated with morbidity and mortality. Any derangements from the normal range of electrolyte levels in the body is described as electrolyte disorders. The Current study was aimed to determine serum electrolytes disorder and its associated factors among adults admitted with metabolic syndrome at Jimma medical center, South West Ethiopia.

Methods

A Facility based cross sectional study was conducted on 256 patients admitted medical center with metabolic syndrome during the study period. The World Health Organization stepwise assessment tools and patients’ medical records were used to collect information on factors associated with electrolyte disorders. Bivariable and Multivariable logistic regression analyses were performed to identify factors associated with electrolyte disorder at the level of significance of p value <0.25 with 95% confidence interval of crude odds ratio and <0.05 with 95% confidence interval of adjusted odds ratio respectively.

Results

The overall prevalence of electrolyte disorders was 44.1% (95%CI:40.99–47.20) with hyponatremia 42.9% (95%CI:39.81–45.99) as the leading electrolyte disorder followed by hypokalemia 20.7% (95%CI:18.17–23.23), hypochloremia 17.6% (95%CI:15.22–19.98) and hypocalcemia 9.4% (95%CI:7.57–11.22). Non-formal education [AOR: 6.81; 95%CI:(3.48,17.01)] alcohol consumption [AOR: 4.28; 95%CI:(1.71,10.70)], diuretics, diuretics [AOR: 4.39; 95%CI:(2.10,9.15)], antidiabetics [AOR: 5.18; 95%CI:(2.44,11.00)], and body mass index [AOR: 11.51; 95%CI:(3.50,18.81)] were identified as independent factors for electrolyte disturbance in multivariable logistic regression.

Conclusion

The finding of the study revealed that nearly half the study participants with metabolic syndromes had electrolyte disorder. Educational status, habit of alcohol consumption, diuretics, antidiabetics, and having higher body mass index were the independent factors associated with electrolyte disorders. Determination of Serum electrolytes, proper administration of diuretic and health education on behavioral factors were the necessary measures that should be done by concerned bodies to reduce electrolytes disorder.

Prevalence and Description of Hyponatremia in a Swiss Tertiary Care Hospital: An Observational Retrospective Study

Background: Hyponatremia (serum sodium concentration <135 mEq/L) is the most common electrolyte abnormality among hospitalized patients. Our aim was to study the epidemiology of hyponatremia in hospitalized patients, as well as the short-term mortality rates, the length of stay (LOS), and associated hospital costs.

Methods: This retrospective cohort study included 6,539 hospitalizations in the internal medicine ward of a Swiss tertiary-care teaching hospital between January 1, 2012, and December 31, 2018 (42.7% women, mean age 69 years). Using serum sodium concentration, we identified hospitalizations with hyponatremia and calculated the prevalence of overall hyponatremia, admission hyponatremia (AH), hospital-acquired hyponatremia (HAH), and persistent hyponatremia (PH) at discharge. We also studied the impact of hyponatremia on 30-day readmissions, in-hospital and 30-day mortality, and hospital LOS and costs, using multivariable logistic regression and Cox proportional hazards models, with normal natremia as reference.

Results: Prevalence of overall hyponatremia was 32.5% [95% confidence interval (CI), 31.3–33.6%], while prevalence of PH among hospitalizations with AH and HAH was 33.7% (31.7–35.8%). After multivariable adjustment, hyponatremia was associated with increased hospital costs (CHF 19,025 ± 485 vs. 14,962 ± 341, p < 0.001) and LOS (13.4 ± 0.2 vs. 10.7 ± 0.2 days, p < 0.001). Increased severity of hyponatremia was associated with higher hospital costs and LOS (p for trend <0.001). There was a trend toward more frequent 30-day readmissions associated with hyponatremia [adjusted odds ratio (OR), 1.15 (1.01–1.31), p = 0.032], mainly with PH: adjusted OR = 1.41 (1.17–1.71), p < 0.001. No association was found between severity of hyponatremia and readmissions. Hyponatremia was associated with an increase of in-hospital [adjusted OR = 1.94 (1.49–2.53), p < 0.001] and 30-day mortality: adjusted OR = 1.80 (1.44–2.24), p < 0.001. Increased severity of hyponatremia was associated with higher in-hospital and 30-day mortality (p for trend < 0.001).

Conclusions: Hyponatremia is highly prevalent among hospitalized patients and associated with an increase of LOS, early hospital readmission, in-hospital and 30-day mortality, and hospital costs. PH was associated with a substantial increase of the risk of early hospital readmission and 30-day mortality.

Risk Factors for 90-day Readmissions With Fluid and Electrolyte Disorders Following Posterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study of the 2012 to 2014 Healthcare Cost and Utilization Project Nationwide Readmissions Database.

OBJECTIVE

To identify risk factors for 30- and 90-day readmission due to fluid and electrolyte disorders following posterior lumbar fusion.

SUMMARY OF BACKGROUND DATA

Thirty- and 90-day readmission rates are important quality and outcome measures for hospitals and physicians. These measures have been tied to financial penalties for abnormally high rates of readmission. Furthermore, complex and high cost surgeries have been increasingly reimbursed in the form of bundled disease resource group payments, where any treatment within 90-day postdischarge is covered within the original bundled payment scheme.

METHODS

A total of 65,121 patients in the Healthcare Cost and Utilization Project Nationwide Readmissions Database met our inclusion criteria, of which 1128 patients (1.7%) were readmitted within 30 days, and 1669 patients (2.6%) were readmitted within 90 days due to fluid and electrolyte abnormalities. A bivariate analysis was performed to compare baseline characteristics between patients readmitted with fluid and electrolyte disorders and the remainder of the cohort. A multivariate regression analysis was then performed to identify independent risk factors for readmission due to fluid and electrolyte disorders at 30 and 90 days.

RESULTS

The strongest independent predictors of 30-day readmissions were age ≥80 years, age 65 to 79 years, age 55 to 64 years, liver disease, and drug use disorder. The five strongest predictors of 90-day readmissions were age ≥80 years, age 65 to 79 years, age 55 to 64 years, liver disease, and fluid and electrolyte disorders.

CONCLUSION

Patients with baseline liver disease, previously diagnosed fluid and electrolyte disorders, age older than 55 years, or drug use disorders are at higher risk for readmissions with fluid and electrolyte disorders following posterior lumbar fusion. Close monitoring of fluid and electrolyte balance in the perioperative period is essential to decrease complications and reduce unplanned readmissions.

LEVEL OF EVIDENCE

3.

Seasonality of Hypoosmolar Hyponatremia in Medical Inpatients - Data from a Nationwide Cohort Study

CONTEXT

Hyponatremia is the most prevalent electrolyte disturbance in hospitalized patients. Previous studies have shown a seasonal variation of profound hyponatremia with higher prevalence during warmer months.

OBJECTIVE

This study aimed at analyzing the seasonal prevalence and sex- and age-specific differences of hyponatremia in medical inpatients.

DESIGN

Nationwide cohort study from January 2009 and December 2015 using prospective administrative data.

SETTING

Medical inpatients.

PATIENTS

Diagnosis of hypoosmolar hyponatremia.

MAIN OUTCOME MEASURES

The primary outcome was the monthly alteration in hyponatremia prevalence. Secondary outcomes were the association of outdoor temperature with hyponatremia prevalence and differences among sex and age groups.

RESULTS

Of 2 426 722 medical inpatients, 84 210 were diagnosed with hypoosmolar hyponatremia, of whom 61% (n = 51 262) were female. The highest overall prevalence of hyponatremia was observed in July (4.5%, n = 8976); the lowest in December (2.7%, n = 6530). The overall prevalence of hyponatremia in women compared with men was higher by 58% (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.56-1.60). The sex-specific difference was most pronounced in the warmest month of July (mean temperature 20.1°C (OR, 1.76; 95% CI, 1.68-1.84). We observed the strongest association between seasonality and hyponatremia in elderly (>80 years) female inpatients admitted during the month of July (OR, 2.40; 95% CI, 2.20-2.62]).

CONCLUSION

The prevalence of diagnosed hypoosmolar hyponatremia in medical inpatients increases during summer months with higher outdoor temperature. Elderly female inpatients were most susceptible to the seasonal rise in hyponatremia prevalence.

Hyponatremia associated with long-term medication use in the elderly: an analysis in general practice

INTRODUCTION The aim of this study is to determine the prevalence of hyponatremia, its association with long-term medication use and underlying chronic conditions, the rate of hospitalisation and death within 3 months from its discovery and its management in community-dwelling older people. METHODS One year of data for ~5635 patients aged >65 years was extracted from the databases of 19 general practitioners (GPs); 2569 (45.6%) were checked for hyponatremia. RESULTS Hyponatremia occurred in 205 (8.0%) of 2569 checked individuals: 78.5% (161/205) had hypertension, 31.2% (64/205) diabetes, 23.9% (49/205) chronic renal failure; 38.0% (78/205) received diuretics, 36.6% (75/205) renin-angiotensin system antagonists (ACE-I/ARB) and 9.8% (20/205) serotonin reuptake inhibitors. Drug consumption was higher in hyponatremic patients, although only diuretics, ACE-I/ARB, anti-arrhythmics and opioids were significantly associated with hyponatremia. The likelihood of hyponatremia trebled when four drugs were taken, and it was seven-fold higher with the use of six drugs. Hyponatremia was associated with a higher prevalence of chronic illnesses and higher rate of hospitalisation (13.7% vs 7.7%, P = 0.005) and death (3.9% vs 1.8%, P < 0.035). The use of at least one long-term medication was associated with hospitalisation or death in hyponatremic patients (10% vs 6.3%, P = 0.010). Less than 20% of hyponatremic patients had their sodium level checked again after 1 month. DISCUSSION Hyponatremia is not uncommon among community-living older patients, especially in patients taking medications potentially causing hyponatremia. Hyponatremic patients are likely to encounter more serious events, including hospitalisation and death. Targeted training of GPs is desirable to improve their practice.

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.

Sarcopenia as a potential cause of chronic hyponatremia in the elderly

Hyponatremia is the most frequent electrolyte disorder found in clinical practice, particularly in hospitalized elderly patients, where it is associated with fractures, falls, hospital readmission, prolonged hospital stay and increased mortality. Pathophysiologically, hyponatremia can be induced by the reduction in sodium or potassium body content, and/or the increase in water body content. Sarcopenia is an ageing-associated progressive and generalized loss of musculoskeletal mass and strength which leads to low physical performance, particularly in the frail elderly. Since muscle mass is the main potassium body store, this condition usually represents a reduced body potassium content. In the present article it is hypothesized that sarcopenia, as a cause of low potassium body content, could induce or co-induce hyponatremia, particularly in elderly individuals suffering from frailty phenotype.

Pituitary macroadenoma presenting as severe hyponatremia: a case report

Background

Hyponatremia is defined as a serum sodium level of less than 135 mEq/L in a patient. Although hyponatremia is not an uncommon laboratory finding, especially in the elderly, hunting for the etiology is a challenging issue for any clinician. The three first-line investigations that are required for further analysis are urine osmolality, serum osmolality, and urinary sodium levels in addition to clinical assessment of volume status.

Case presentation

A 69-year-old previously well Sinhalese man presented with lethargy, loss of appetite, vomiting, and altered behavior of 1 week’s duration. An examination revealed Glasgow Coma Scale of 13/15 and marginally low blood pressure. Initial serum sodium level was 104 mmol/L, and plasma and urinary osmolalities were 251 mOsm/kg and 305 mOsm/kg, respectively. His urinary sodium level of 158 mmol/L was suggestive of a clinical picture of a syndrome of inappropriate secretion of antidiuretic hormone. Even after correction of hyponatremia with intravenously administered 3% saline, a persistent altered behavior necessitated cerebral imaging that confirmed the presence of pituitary macroadenoma. Meanwhile, his hormone profile showed very low serum cortisol and low free tetraiodothyronine levels. An ultrasound scan of his abdomen affirmed the presence of normal adrenal glands. With intravenously administered hydrocortisone and orally administered levothyroxine replacement, he showed marked clinical improvement that supported the diagnosis of hypopituitarism.

Conclusion

Hyponatremia in the elderly is not an uncommon presentation. However, etiological diagnosis is a challenging task as there are multiple overlapping differential diagnoses.

Aging increases the expression of vasopressin receptors in both the kidney and urinary bladder

AIMS

The goal of this study was to determine whether aging effects the expression of V_1a and V₂ vasopressin receptors in the urinary bladder mucosa (UBM) and kidney.

METHODS

UBM and kidneys were obtained from young (3 months-of-age) and old (25-30 months-of-age) female Fisher 344 rats. Tissue samples were analyzed by western blotting for V_1a and V₂ receptor expression, and rat plasma levels of vasopressin levels were measured by ELISA.

RESULTS

V_1a and V₂ receptors were detected in both the UBM and kidneys. Aging significantly (P < 0.05) increased the expression of V₂ receptors by 2.80 ± 0.52 and 6.52 ± 1.24-fold in the UBM and kidneys, respectively. Aging also increased V_1a receptor expression in the kidneys (5.52 ± 1.05 fold; P < 0.05), but not in the UBM. To the best of our knowledge, because this is the first detection of V₂ receptors in the mammalian bladder mucosa, we also probed human UBM for V₂ receptors and observed high expression in human UBM. Unlike V_1a and V₂ receptors, aging had only a minor effect on plasma vasopressin levels (8% increase).

CONCLUSIONS

V₂ receptors are substantially increased in the aging UBM. The role of these receptors in UBM is as yet undefined, but given their presence and action in the kidneys, the possible effect of these receptors in free water regulation should be considered. The large age-related increase in the expression of V₂ receptors in both the UBM and kidney may contribute to the effectiveness of desmopressin in age-related nocturia.

The Association of Hyponatremia, Risk of Confusional State, and Mortality

BACKGROUND

Hyponatremia and delirium are frequent problems in older hospitalized patients. Although confusional states are considered to be a possible complication of hyponatremia, there has been no systematic study to date of the precise prevalence of delirium among patients with hyponatremia and its effect on long-term outcomes.

METHODS

In a 13-month period in 2009/2010, all patients with a serum sodium level less than or equal to 130 mmol/L (the hyponatremia group) in a cohort of hospitalized older patients were studied and compared to a normonatremic control group of patients who were matched for age, sex, and diagnosis group. The prevalence of delirium was determined by two-stage examination. Inhospital mortality, mortality six months after initial examination, and functional status were prospectively analyzed.

RESULTS

179 patients were identified whose serum sodium level was less than or equal to 130 mmol/L (7.9% of all treated patients), of whom 141 were included in the hyponatremia group. The mean age of the participants was 83 (range, 63-102), and 84% were women. Patients with hyponatremia suffered more often from delirium (22.7% versus 8.5%; p = 0.002) and had a higher inhospital mortality (10.6% versus 2.1%; p = 0.005). The mortality six months after initial examination was 31.9% versus 22.7% (p = 0.080). 59.7% of patients in the hyponatremia group and 49% in the control group (p = 0.146) needed a higher level of chronic care after discharge than they had needed before the hospitalization.

CONCLUSION

Hyponatremia in hospitalized older patients is associated with a higher likelihood of delirium and an elevated in-hospital mortality.

Hyponatremia in the elderly: challenges and solutions

Decreased serum sodium concentration is a rather frequent electrolyte disorder in the elderly population because of the presence of factors contributing to increased antidiuretic hormone, the frequent prescription of drugs associated with hyponatremia and also because of other mechanisms such as the “tea and toast” syndrome. The aim of this review is to present certain challenges in the evaluation and treatment of hyponatremia in the elderly population and provide practical solutions. Hyponatremia in elderly subjects is mainly caused by drugs (more frequently thiazides and antidepressants), the syndrome of inappropriate antidiuretic hormone secretion (SIAD) or endocrinopathies; however, hyponatremia is multifactorial in a significant proportion of patients. Special attention is needed in the elderly population to exclude endocrinopathies as a cause of hyponatremia before establishing the diagnosis of SIAD, which then requires a stepped diagnostic approach to reveal its underlying cause. The treatment of hyponatremia depends on the type of hyponatremia. Special attention is also needed to correct serum sodium levels at the appropriate rate, especially in chronic hyponatremia, in order to avoid the osmotic demyelination syndrome. In conclusion, both the evaluation and the treatment of hyponatremia pose many challenges in the elderly population.

Transurethral Resection of the Prostate, Bladder Explosion and Hyponatremic Encephalopathy: A Rare Case Report of Malpractice

We present an original case report of a bladder explosion during a TURP intervention for benign prostatic hypertrophy, that was brought on by the absorption of about 5 liters of glycine 1.5% and then onset of a severe hyponatremia. The quick and inappropriate correction of this electrolyte imbalance led the onset of encephalopathy and the death of the patient. The authors discuss the pathogenesis of these uncommon diseases and, considering the most recent Italian Legislation, they highlight the importance to respect good clinical practice standards and guidelines to ensure the most appropriate treatments for the patient and remove any assumptions of medical liability.

Patterns of Drug Use and Serum Sodium Concentrations in Older Hospitalized Patients: A Latent Class Analysis Approach

BACKGROUND

Several drugs may lower serum sodium concentrations (NaC) in older patients. However, distinguishing their individual effects is particularly difficult in this population because of the high prevalence of polypharmacy and disease states that are per se associated with hyponatremia.

OBJECTIVES

Our objective was to identify specific patterns of medication use in older hospitalized patients and determine whether these patterns were associated with serum NaC.

METHODS

We collected clinical and demographic data, pre-admission drugs, Drug Burden Index (DBI) score, and average NaC during hospitalization in a consecutive series of older medical patients (n = 101, mean ± standard deviation [SD] age 87 ± 6 years). We used latent class analysis (LCA) to identify specific patterns of drug use and multivariate regression to determine the associations between 14 separate drug classes, identified patterns of drug use, and NaC.

RESULTS

LCA revealed three patterns: lower overall drug use (class 1), anticoagulant use and higher drug use (class 2), and antiplatelet use (class 3). Mean (±SD) DBI score in each class was 2.7 ± 1.3, 3.3 ± 1.6, and 2.4 ± 1.5, respectively (p = 0.04). Mean (± SD) NaC in classes 1, 2, and 3 were 140.6 ± 6.8, 138.7 ± 5.3, and 136.5 ± 4.7 mmol/l, respectively (p = 0.006). After adjustment for age, sex, Charlson Comorbidity Index score, estimated glomerular filtration rate (eGFR), DBI score, and digoxin use, mean NaC in class 2 and class 3 was significantly lower than in class 1 (-3.9 mmol/l; 95% confidence interval [CI] -7.1 to -0.8, p = 0.01 and -5.2 mmol/l; 95% CI -7.9 to -2.5, p < 0.001, respectively). Mean serum NaC was not significantly associated with any of the 14 individually assessed drug classes. In addition to latent class, increasing age and higher eGFR were also independently associated with lower serum NaC (p = 0.002 and p = 0.03, respectively).

CONCLUSION

LCA enabled us to identify patterns of drug use associated with lower serum NaC in older inpatients. Our results suggest that older patients using antiplatelets or anticoagulants are especially at risk of lower serum NaC.

Severe Hyponatremia due to Levofloxacin Treatment for Pseudomonas aeruginosa Community-Acquired Pneumonia in a Patient with Oropharyngeal Cancer

Hyponatremia (serum Na levels of <135 mEq/L) is the most common electrolyte imbalance encountered in clinical practice, affecting up to 15–28% of hospitalized patients. This case report refers to a middle-aged man with severe hyponatremia due to Syndrome of Inappropriate Antidiuretic Hormone Secretion related to four possible etiological factors: glossopharyngeal squamous cell carcinoma, cisplatin treatment, right basal pneumonia with Pseudomonas aeruginosa, and the treatment with Levofloxacin. This case report discusses a rare complication of common conditions and of a common treatment. To our knowledge this is the first case of hyponatremia related to Levofloxacin and the second related to fluoroquinolones.

Health effects of desalinated water: Role of electrolyte disturbance in cancer development

This review contends that "healthy" water in terms of electrolyte balance is as important as "pure" water in promoting public health. It considers the growing use of desalination (demineralization) technologies in drinking water treatment which often results in tap water with very low concentrations of sodium, potassium, magnesium and calcium. Ingestion of such water can lead to electrolyte abnormalities marked by hyponatremia, hypokalemia, hypomagnesemia and hypocalcemia which are among the most common and recognizable features in cancer patients. The causal relationships between exposure to demineralized water and malignancies are poorly understood. This review highlights some of the epidemiological and in vivo evidence that link dysregulated electrolyte metabolism with carcinogenesis and the development of cancer hallmarks. It discusses how ingestion of demineralized water can have a procarcinogenic effect through mediating some of the critical pathways and processes in the cancer microenvironment such as angiogenesis, genomic instability, resistance to programmed cell death, sustained proliferative signaling, cell immortalization and tumorigenic inflammation. Evidence that hypoosmotic stress-response processes can upregulate a number of potential oncogenes is well supported by a number studies. In view of the rising production and consumption of demineralized water in most parts of the world, there is a strong need for further research on the biological importance and protean roles of electrolyte abnormalities in promoting, antagonizing or otherwise enabling the development of cancer. The countries of the Gulf Cooperative Council (GCC) where most people consume desalinated water would be a logical place to start this research.

Antidepressants and the risk of hyponatremia: a Danish register-based population study

OBJECTIVE

To examine the association between classes of antidepressants and hyponatremia, and between specific antidepressants and hyponatremia.

DESIGN

Retrospective register-based cohort study using nationwide registers from 1998 to 2012.

SETTING

The North Denmark Region.

PARTICIPANTS

In total, 638 352 individuals were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Plasma sodium was obtained from the LABKA database. The primary outcome was hyponatremia defined as plasma sodium (p-sodium) below 135 mmol/L and secondary outcome was severe hyponatremia defined as p-sodium below 130 mmol/L. The association between use of specific antidepressants and hyponatremia was analysed using multivariable Poisson regression models.

RESULTS

An event of hyponatremia occurred in 72 509 individuals and 11.36% (n=6476) of these events happened during treatment with antidepressants. Incidence rate ratios and CIs for the association with hyponatremia in the first p-sodium measured after initiation of treatment were for citalopram 7.8 (CI 7.42 to 8.20); clomipramine 4.93 (CI 2.72 to 8.94); duloxetine 2.05 (CI 1.44 to 292); venlafaxine 2.90 (CI 2.43 to 3.46); mirtazapine 2.95 (CI 2.71 to 3.21); and mianserin 0.90 (CI 0.71 to 1.14).

CONCLUSIONS

All antidepressants except mianserin are associated with hyponatremia. The association is strongest with citalopram and lowest with duloxetine, venlafaxine and mirtazapine.

T-type calcium channels contribute to calcium disturbances in brain during hyponatremia

Disturbance of calcium homeostasis is implicated in the normal process of aging and brain pathology prevalent in the elderly such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis. Previous studies demonstrated that applying a hyponatremic iso-osmotic (low-NaCl) artificial cerebrospinal fluid (ACSF) to rodent hippocampus causes extracellular calcium to rapidly decrease. Restoring normonatremia after low-NaCl treatment causes a rapid increase in extracellular calcium that overshoots baseline. This study examined the amplitude, timing, and mechanism of these surprising calcium changes. We also tested whether hyponatremia increased calcium entry into brain cells or calcium binding to chondroitin sulfate (CS), a negatively charged constituent of the extracellular matrix (ECM) that may be occupied by sodium during normonatremia. We report three major findings. First we show that CS does not contribute to extracellular calcium changes during low-NaCl treatments. Second, we show that the time to minimum extracellular calcium during low-NaCl treatment is significantly shorter than the time to maximum extracellular calcium in recovery from low-NaCl treatment. Third, we show that the decrease in extracellular calcium observed during hyponatremia is attenuated by ML 218, a highly selective T-type calcium channel blocker. Together these data suggest that calcium rapidly enters cells at the onset of low-NaCl treatment and is extruded from cells when normonatremia is restored. Calcium binding to CS does not significantly contribute to calcium changes in brain during hyponatremia. Differences in timing suggest that extracellular calcium changes during and in recovery from hyponatremia occur by distinct mechanisms or by a multistep process. Finally, partial block of extracellular calcium influx by ML 218 suggests that T-type channels are involved in calcium entering cells during hyponatremia. Given the high prevalence of hyponatremia among elderly patients and the growing understanding of calcium's role in multiple neurologic pathologies, this study promotes a novel approach for studying and potentially preventing the effects of hyponatremia on calcium dysregulation in brain tissue.

Hyponatremia in the outpatient setting: clinical characteristics, risk factors, and outcome

PURPOSE

Hyponatremia is a common disorder and hyponatremia in the outpatient setting is not extensively studied. Our aim was to investigate the characteristics of hyponatremia in ambulatory patients.

METHODS

Seventy-six adult outpatients with hyponatremia were enrolled in this prospective study. Demographic features, presenting symptoms and signs, associating morbidities, medications, laboratory findings, mortalities, and length of hospital stay, were recorded.

RESULTS

Mean age was 74.7 ± 12.7 years, and 52 (68.4 %) were female whereas 24 (31.6 %) were male. Mean sodium concentration was 123.6 ± 6.6 mEq/L. Leading cause was thiazide diuretic use (n = 37, 48.7 %) and approximately half of the patients (n = 40, 52.6 %) had a multifactorial etiology. Severe hyponatremia (sodium < 125 mEq/L) was identified in 37 (48.7 %). Thiazide diuretic use, vomiting, and apathy were independent predictors of severe hyponatremia. Eight (10.5 %) patients had a mortal course. A relatively younger age, male gender, presenting sign of lethargy, associating morbidities of malignancy, chronic liver disease, and hypoalbuminemia were risk factors for mortality.

CONCLUSIONS

Hyponatremia is prevalent among elderly, especially in women and with thiazide diuretics. Apart from the trend toward sodium depletion observed in healthy elderly which occurs due to changes in the tubular handling of sodium, a multifactorial etiology including thiazides seems to predict the occurrence and the severity of hyponatremia. Hyponatremia may be a significant cause of mortality in seniors. A relatively younger age, male gender, association of cirrhosis, malignancy, and hypoalbuminemia predict mortality. In elderly outpatients, identification of the risk factors for hyponatremia and close monitoring are imperative to reduce the related mortality and morbidity.

Dehydration, Hypernatremia, and Hyponatremia

Disturbances of serum sodium are one of the most common findings in older persons. They are also a major cause of hospital admissions and delirium and are associated with frailty, falls, and hip fractures. Both hypernatremia and hyponatremia are potentially preventable. Treatment involves treating the underlying cause and restoring sodium and volume status to normal. The arginine vasopressin antagonists, vaptans, have increased the therapeutic armamentarium available to physicians.

Employment of vasopressin receptor antagonists in management of hyponatraemia and volume overload in some clinical conditions

WHAT IS KNOWN AND OBJECTIVE

Hyponatraemia, the most common electrolyte imbalance occurring in hospitalized subjects, is usually classified as hypovolaemic, euvolaemic or hypervolaemic. Hyponatraemia is a predictor of death among subjects with chronic heart failure and cirrhosis. The inappropriate secretion of the antidiuretic hormone (AVP) seems to be of pivotal importance in the decline of serum sodium concentration in these clinical conditions. The objective of this review was to summarize recent progress in management of hyponatraemia in SIADH, cirrhosis and heart failure.

METHODS

Literature searches were conducted on the topics of hyponatraemia and vasopressin receptor antagonists, using PubMed, pharmaceutical company websites and news reports. The information was evaluated for relevance and quality, critically assessed and summarized.

RESULTS AND DISCUSSION

The initial treatment of severe hyponatraemia is directed towards the prevention or management of neurological manifestations and consists of an intravenous infusion of hypertonic saline. Fluid restriction is indicated in oedematous states. Diuretics alone or in combination with other specific drugs remain the main strategy in the management of volume overload in heart failure. In resistant cases, ultrafiltration can lead to effective removal of isotonic fluid preventing new episodes of decompensation; however, aquapheresis is associated with increased costs and other limits. In several trials, the efficacy of vasopressin receptor antagonists in euvolaemic patients (inappropriate antidiuretic hormone secretion) or in hypervolaemic hyponatraemia (chronic heart failure, cirrhosis) has been evaluated. It was found that vaptans, which promote aquaresis, were superior to a placebo in raising and maintaining serum sodium concentrations in these subjects.

WHAT IS NEW AND CONCLUSIONS

Combined with conventional therapy, vasopressin receptor antagonists (AVP-R antagonists) are able to increase the excretion of electrolyte-free water and the sodium concentration. Further studies are needed to assess efficacious outcomes of aquaresis compared with aquapheresis and with conventional therapy.

Hyponatremia: Special Considerations in Older Patients

Hyponatremia is especially common in older people. Recent evidence highlights that even mild, chronic hyponatremia can lead to cognitive impairment, falls and fractures, the latter being in part due to bone demineralization and reduced bone quality. Hyponatremia is therefore of special significance in frail older people. Management of hyponatremia in elderly individuals is particularly challenging. The underlying cause is often multi-factorial, a clear history may be difficult to obtain and clinical examination is unreliable. Established treatment modalities are often ineffective and carry considerable risks, especially if the diagnosis of underlying causes is incorrect. Nevertheless, there is some evidence that correction of hyponatremia can improve cognitive performance and postural balance, potentially minimizing the risk of falls and fractures. Oral vasopressin receptor antagonists (vaptans) are a promising innovation, but evidence of their safety and effect on important clinical outcomes in frail elderly individuals is limited.

Epidemiology, symptoms, and treatment characteristics of hyponatremic psychiatric inpatients

Hyponatremia is a common phenomenon in psychiatry occurring as an adverse effect to drugs or following polydipsia. We performed a retrospective in-depth analysis of hyponatremia cases in a large unselected population of psychiatric inpatients. During a 3-year period, all cases of hyponatremia were identified among patients admitted to a large psychiatric state and university hospital by the institution's electronic laboratory database. Demographic, treatment-related, and laboratory data were obtained by consecutive chart review, respectively. Hyponatremia occurred in 347 (4.9%) of 7113 cases, of which the majority (78%) displayed only a mild manifestation. Symptoms were recorded in 28.8% of cases, already occurred in mild forms, and comprised gait impairment (45%, including falls), confusion (30%), sedation (26%), and dyspepsia (41%). Age, female sex, nonpsychiatric drug polypharmacy-particularly with thiazides and/or angiotensin-converting enzyme inhibitors-and diagnosis of a mood disorder were associated with more severe hyponatremia, respectively. The proportion of hyponatremic patients treated with venlafaxine, trazodone, carbamazepine, oxcarbazepine, and first-generation antipsychotics, respectively, was significantly higher in the hyponatremia sample than in the normonatremic population. This was, surprisingly, not the case with selective serotonin reuptake inhibitors or any other antidepressant drug class. We found prescription with second-generation antipsychotics to be significantly associated with less severe hyponatremia.Hyponatremia may be mainly attributed to the syndrome of inappropriate antidiuretic hormone secretion, as indicated by decreased serum osmolarity in our sample. Besides old age and female sex, treatment with certain drugs-rather than whole drug classes-carries a substantially increased risk.

Prevalence of hyponatremia and association with mortality: results from NHANES

BACKGROUND

Hyponatremia is the most common electrolyte abnormality in hospitalized patients and is associated with adverse outcomes, but its prevalence and significance in the general US population is unknown. Our aims were to determine the prevalence of hyponatremia and its association with mortality in the population.

METHODS

We performed a population-based, cross-sectional study of 14,697 adults aged ≥ 18 years who participated in the nationally representative National Health and Nutrition Examination Survey for 1999-2004. By using measurements of serum sodium corrected for dilutional effect of hyperglycemia, we determined the association of hyponatremia with patient characteristics, comorbidities, and prescription medications, and performed unadjusted and adjusted Cox proportional hazards regression to find the association of hyponatremia with all-cause mortality.

RESULTS

We provide the first estimate of the prevalence of hyponatremia in the US population, which in our weighted analysis was 1.72%. Prevalence of hyponatremia was significantly higher in women (2.09%, P = .004) and increased with age. Hyponatremia was more common in subjects with hypertension, diabetes, coronary artery disease, stroke, chronic obstructive pulmonary disease, cancer, and psychiatric disorders, and less common in those with no comorbidities (1.04%, P < .001). There was a significant risk of death associated with hyponatremia in unadjusted (hazard ratio [HR], 3.61; P < .001) and adjusted Cox models controlling for demographics, smoking, comorbidities, and insurance status (HR, 2.43; P < .001). There was a U-shaped relationship between serum sodium and HR for mortality.

CONCLUSIONS

Our findings suggest that hyponatremia is a predictor of mortality in the general population independently of age, gender, and comorbid conditions.