Hyponatremia: incidence, risk factors, and consequences in the elderly in a home-based primary care program

The Influence of Hyponatremia and Hypokalemia on the Risk of Fractures in Various Anatomical Regions among Adult Trauma Patients: A Propensity Score-Matched Analysis

BACKGROUND

Hyponatremia and hypokalemia are common electrolyte imbalances in trauma patients and have been identified to be risk factors for a fall. In addition, hyponatremia was reported to be related to osteoporosis and fragility fractures, while the association between hypokalemia and osteoporosis has only been reported in rare case reports. This study investigated the impact of hyponatremia and hypokalemia on the incidence of fractures in various body regions of adult trauma patients, using the propensity score-matched patient cohort to reduce the influence of patients' baseline characteristics.

METHODS

The study analyzed data from 11,173 hospitalized adult trauma patients treated from 1 January 1998, to 31 December 2022. The study included 1968 patients with hyponatremia and 9205 without, and 1986 with hypokalemia and 9187 without. Different 1:1 propensity score-matched cohorts were generated to create the 1903 pairings of patients with or without hyponatremia, 1977 pairings of patients with or without hypokalemia, and 380 pairing of patients with both hyponatremia and hypokalemia vs. normal control patients. Analysis was conducted on the incidence of fracture in various anatomic regions.

RESULTS

Hyponatremic patients had increased odds of thoracic vertebral fracture [odds ratio (95% confidence interval) 1.63 (1.10-2.42), p = 0.014], pelvic fracture [2.29 (1.12-4.67), p = 0.019], and femoral fracture [1.28 (1.13-1.45), p < 0.001] but decreased odds of radial and patella fractures. Hypokalemic patients showed no significant differences in fracture risk except for a decreased likelihood of radial fractures. The patients with both hyponatremia and hypokalemia showed a decreased likelihood of radial fractures and patella fractures.

CONCLUSION

Hyponatremia may have a greater impact on the occurrence of bone fractures than hypokalemia in trauma patients who have suffered a fall. Electrolyte abnormalities should be taken into account while assessing the risk of fractures in trauma patients.

Prevalence, Risk Factors, and Mortality of Patients Presenting with Moderate and Severe Hyponatremia in Emergency Departments

Background

Hyponatremia is among the most common electrolyte disturbances encountered in clinical practice and is associated with a high rate of morbidity and mortality. However, there are very limited data on adult cases presenting to emergency departments with hyponatremia.

Objectives

This study aimed to evaluate the frequency, clinical characteristics, and outcomes in hyponatremic patients presenting to emergency departments.

Methods

This retrospective study analyzed all patients older than 18 years who visited our institution's emergency department between October 2018 and October 2019 and has a serum sodium (Na) level <130 mmol/L.

Results

Among 24,982 patients who visited the emergency department and had a documented serum sodium level, 284 were included. Patients' median age was 67.13 ± 14.8 years. Younger patients are less likely to develop severe hyponatremia compared to older patients (adjusted odds ratio (AOR): 0.415; 95% confidence interval (CI): 0.231-0.743; p=0.003). Asymptomatic hyponatremia and gastrointestinal manifestations were the most common presenting hyponatremia symptoms (33.7% and 24.2%, respectively). Proton pump inhibitor (PPI) use, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACE/ARB) use, and spironolactone use (OR = 2.6 and 3.9, 2.3 with a p=0.02, 0.03, and 0.05, respectively) were associated with increased odds of severe hyponatremia. There is no difference in the overall mortality rate within 6 months of presentation between severe and moderate hyponatremia groups (11.1% versus 16.2%, p=0.163).

Conclusion

Moderate and severe hyponatremia are not uncommon among patients presenting to emergency departments. Moderate hyponatremia can be asymptomatic with clinical significance. Older patients, use of PPI, use of ACEi/ARBs, and spironolactone use were associated with an increased risk of severe hyponatremia compared to moderate. Further prospective analysis of a larger population is needed to confirm our findings.

Hyponatremia and aging-related diseases: key player or innocent bystander? A systematic review

BACKGROUND

Hyponatremia is frequent in older age; whether it is a key player, a surrogate marker, or an innocent bystander in age-related diseases is still unclear.

OBJECTIVE

To understand the role of hyponatremia in falls, osteoporosis, fractures, and cognitive impairment in old patients.

METHOD

Eligibility criteria for study inclusions were: written in English, peer-reviewed observational and intervention studies, clinical trial, prospective and retrospective controlled cohort studies, and case-controlled studies without limitations regarding the date of publication.

INFORMATION SOURCES

Protocol available on the International Prospective Register of Systematic Reviews (PROSPERO, CRD42021218389). MEDLINE, Embase, and PsycINFO were searched. Final search done on August 8, 2021. Risk-of-bias assessment: Risk-of-Bias Assessment tool for Non-randomized Studies (RoBANS) and the Bradford Hill's criteria for causality.

RESULTS

Includes studies: One-hundred thirty-five articles retained for the revision. Synthesis of results - Falls: Eleven studies were included. Strong association between hyponatremia and falls in all the studies was found. Osteoporosis and fractures: nineteen articles were included. The association between hyponatremia and osteoporosis is unclear. Cognitive impairment: Five articles were included. No association between hyponatremia and cognitive impairment was found.

DISCUSSION

Interpretation: Falls, osteoporosis, and fractures are multifactorial. Hyponatremia is not temporally related with the outcomes; we suggest that hyponatremia may be regarded as a marker of unhealthy aging and a confounder instead of a causal factor or an innocent bystander for falls and fractures. Concerning cognitive impairment, there are no evidence supporting a real role of hyponatremia to be regarded as an innocent bystander in neurodegeneration.

Hyponatremia in the frail

As the lifespan increases, special attention has been given to the supportive care needs of the elderly. Frailty is an important issue in third age, since it is related to poor quality of life and mortality. The prevalence of pathological conditions related to sodium levels, specifically hyponatremia, is also present in the elderly. Yet, it is unclear, if hyponatremia and frailty are related to each other. This review summarizes the current state of knowledge regarding hyponatremia and frailty and analyzes five independent studies which searched for an association between those two parameters. As indicated by this study results, hyponatremia consists a risk factor for frailty. This could be explained by an effect of hyponatremia on sarcopenia and on cognitive function, which consist components of frailty. Thus, it is essential to monitor sodium levels in the elderly and to develop related interventions (e.g. using arginine vasopressin antagonists) in order to prevent frailty.

Low Creatininuria due to Hyponatremia Is Reversible in Many Patients

BACKGROUND

Chronic hyponatremia has been reported to be associated with low solute intake and low creatinine excretion (reflecting likely sarcopenia). We wanted to study the effect, on the long term, of correction of hyponatremia on solute and creatinine excretion in chronic SIADH.

METHODS

We made a retrospective review of clinical and biochemical data of patients with euvolemic hyponatremia. We analyzed 24-h urine solute and creatinine excretion in volunteers with hyponatremia induced by dDAVP over 4 days, in 12 patients with chronic SIADH (>1 month) before and after a few days of SNa correction and in 12 patients (6 women and 6 men) before and after 3 months of SNa correction by a vaptan or urea.

RESULTS

We confirm a low urine creatinine and solute excretion only in patients with chronic hyponatremia (>1 month). Correction of SNa (from 127 ± 2.3 mEq/L to 139 ± 2.8 mEq/L) for >3 months, in the 12 patients (mean age 58 ± 18), was associated with an increase in 24-h creatinine excretion (from 986 ± 239 to 1,238 ± 220 mg; p < 0.02) and in patients treated with a vaptan (n = 5) solute excretion increased from 656 ± 207 mmol/24 h to 960 ± 193 mmol/24 h (p < 0.02). Sodium excretion increased also in the 12 patients (from 100 ± 53 mEq/24 h to 169 ± 38 mEq/24 h; p < 0.01).

CONCLUSION

Chronic hyponatremia (>1 month) is associated with a decrease in solute output (or intake) and in creatinine excretion. In many patients, these abnormalities are reversible in the long term.

Routine postoperative fluid restriction to prevent syndrome of inappropriate antidiuretic hormone secretion after transsphenoidal resection of pituitary adenoma

OBJECTIVE

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common problem during the postoperative course after pituitary surgery. Although treatment of this condition is well characterized, prevention strategies are less studied and reported. The authors sought to characterize outcomes and predictive factors of SIADH after implementation of routine postoperative fluid restriction for patients undergoing endoscopic transsphenoidal surgery for pituitary adenoma.

METHODS

In March 2018, routine postoperative fluid restriction to 1000 ml/day for 7 days was instituted for all patients who underwent surgery for pituitary adenoma. These patients were compared with patients who underwent surgery for pituitary adenoma between March 2016 and March 2018, prior to implementation of routine fluid restriction. Patients with preoperative history of diabetes insipidus (DI) or concern for postsurgical DI were excluded. Patients were followed by neuroendocrinologists and neurosurgeons, and sodium levels were checked between 7 and 10 days postoperatively. SIADH was defined by a serum sodium level less than 136 mmol/L, with or without symptoms within 10 days after surgery. Thirty-day readmission was recorded and reviewed to determine underlying reasons.

RESULTS

In total, 82 patients in the fluid-unrestricted cohort and 135 patients in the fluid-restricted cohort were analyzed. The patients in the fluid-restricted cohort had a significantly lower rate of postoperative SIADH than patients in the fluid-unrestricted cohort (5% vs 15%, adjusted OR [95% CI] 0.1 [0.0-0.6], p = 0.01). Higher BMI was associated with lower rate of postoperative SIADH (adjusted OR [95%] 0.9 [0.9-1.0], p = 0.03), whereas female sex was associated with higher rate of SIADH (adjusted OR [95% CI] 3.1 [1.1-9.8], p = 0.03). There was no difference in the 30-day readmission rates between patients in the fluid-unrestricted and fluid-restricted cohorts (4% vs 7%, adjusted OR [95% CI] 0.5 [0-5.1], p = 0.56). Thirty-day readmission was more likely for patients with history of hypertension (adjusted OR [95% CI] 5.7 [1.3-26.3], p = 0.02) and less likely for White patients (adjusted OR [95% CI] 0.3 [0.1-0.9], p = 0.04).

CONCLUSIONS

Routine fluid restriction reduced the rate of SIADH in patients who underwent surgery for pituitary adenoma but was not associated with reduction in 30-day readmission rate.

Hyperacute hyponatremia mimicking acute ischemic stroke: A case report

We present a case of hyperacute hyponatremia with stroke like symptoms on presentation. Symptoms included confusion, left-sided facial droop, right-sided hemiparesis, dysarthria and aphasia, with an NIH stroke score of 5. Sodium level at the time of presentation was 119 mmol/L which dropped acutely from 138 mmol/L seven hours prior. Symptoms improved after treatment with 3% saline and no evidence of stroke, intracranial hemorrhage or space-occupying lesion was seen on imaging. The most likely cause of the hyponatremia was increased free water consumption and ADH surge. The patient remained symptom free after discharge with resolution of hyponatremia. Acute hyponatremia can cause focal neurological complaints and deficits, mimicking acute ischemic stroke. We advise clinicians to be aware of this entity when considering interventions for possible acute ischemic stroke and evaluating a patient with focal neurological deficits.

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.

Analysis of the Frequency and Onset Time of Hyponatremia/Syndrome of Inappropriate Antidiuretic Hormone Induced by Antidepressants or Antipsychotics

BACKGROUND

Hyponatremia and syndrome of inappropriate antidiuretic hormone (SIADH) is a potentially fatal adverse effect of antidepressants (ADs) and antipsychotics (APs), although its frequency and onset time have not been well documented.

OBJECTIVE

To analyze the frequency and onset time of AD- or AP-induced hyponatremia/SIADH.

METHODS

We used plural data-mining techniques to search the US Food and Drug Administration Adverse Event Reporting System (FAERS) database for reports on hyponatremia/SIADH induced by psychotropic drugs from January 2004 to June 2020. For each item, we assessed the reporting odds ratio, 95% CI, median onset time, and Weibull distribution parameters.

RESULTS

We identified 36 422 reports related to hyponatremia/SIADH. Signals were detected for all psychotropic drugs that we analyzed, except for clozapine. The median onset time of total AD-induced hyponatremia/SIADH was shorter than that of AP. For all ADs and APs except clozapine, hazards were considered to be the early failure type. In contrast, the hazard of clozapine was considered to be the random failure type. The limitations of this study included several reporting biases and the presence of confounding variables, particularly age.

CONCLUSION AND RELEVANCE

Most ADs and APs were found to be associated with a risk for hyponatremia/SIADH. In addition, sufficient attention should be paid to signs of hyponatremia/SIADH in the early phase when most ADs and APs are administered. These data are potentially useful for determining AD- or AP-induced hyponatremia/SIADH in the early stage and for preventing its further aggravation into a serious condition.

Active management of hyponatraemia and mortality in older hospitalised patients compared with younger patients: results of a prospective cohort study

INTRODUCTION

Hyponatraemia is associated with increased morbidity and mortality; the aetiology and outcomes of hyponatraemia in older patients have not been defined in prospective studies.

METHODS

A single-centre 9-month prospective observational study in which clinical outcomes in hospitalised patients ≥ 65 years (older patients with hyponatraemia (OP-HN)) and those <65 years (young patients with hyponatraemia (YP-HN)) with hyponatraemia were analysed, and compared with eunatraemic controls (older patients with normonatraemia (OP-NN) and young patients with normonatraemia (YP-NN)).

RESULTS

In total, 1,321 episodes of hyponatraemia in 1,086 patients were included; 437 YP-HN, median age 54 years (IQR 44,60) and 884 OP-HN, median age 77 years (IQR 71,82). A total of 1,120 consecutive eunatraemic control patients were simultaneously recruited; 690 OP-NN, median age 77 years (IQR 71,83) and 430 YP-NN, median age 52 years (IQR 41,58). Euvolaemic hyponatraemia was the commonest cause of hyponatraemia in both age groups (48% in YP-HN and 46% in OP-HN). Sixty-two percent of OP-HN received hyponatraemia-directed treatment within the initial 48 h, compared with 55% of YP-HN, P = 0.01. Despite the greater treatment rates in OP-HN, younger patients were 24% more likely to be discharged with normal plasma sodium concentration (pNa) compared with older patients, relative risk (RR) 1.24 (95% confidence interval (CI) 1.12-1.37), P < 0.001.Using OP-NN as the reference group, the RR of in-hospital death in OP-HN was 2.15 (95% CI 1.3-3.56), P = 0.002. Using YP-NN as the reference group, the RR of in-hospital death in YP-HN was 4.34 (95% CI 1.98-9.56), P < 0.001.

CONCLUSION

Despite greater rates of HN-targeted treatment, the risk of in-hospital death is increased in older hyponatraemic patients compared with older eunatraemic controls. The impact of hyponatraemia on mortality is even greater in younger patients.

Prevalence of hyponatremia among older inpatients in a general hospital

PURPOSE

This study aimed to explore the incidence, clinical features, etiology, and mortality of hyponatremia in older inpatients and thus provide preliminary data for an epidemiological study.

METHODS

Hospitalized older patients diagnosed with hyponatremia at the First Medical Center of PLA General Hospital during January 2013-December 2016 were stratified by serum sodium concentrations into mild (130- < 135 mmol/L), moderate (125- < 130 mmol/L) and severe hyponatremia groups (< 125 mmol/L). Etiologies, medication histories, hospitalization times, and outcomes were analyzed.

RESULTS

During the indicated period, 4364 older patients with hyponatremia were hospitalized, including 2934 men and 1430 women with an average age of 84.6 ± 3.5 years (range 80-104 years). The prevalence of hyponatremia was 24.7%. An analysis of common primary diseases identified respiratory diseases as the most frequent (25.0%), followed by tumors (23.1%), cardiovascular diseases (19.9%), central nervous system diseases (8.9%), and orthopedic diseases (6.1%). PPIs (59.7%), loop diuretics (57.4%), potassium-preserving diuretics (29.5%), ACEIs/ARBs (20.0%), thiazide diuretics (12.5%), and NSAIDs (12.4%) were the drugs most commonly associated with hyponatremia. The in-hospital mortality rate was 11.7%. Aggravated hyponatremia led to a prolonged hospitalization time. Moreover, when compared with mild hyponatremia, moderate and severe hyponatremia were associated with significant increases in in-hospital mortality (ORs 1.89 and 2.66, respectively; 95% CIs 1.54-2.33 and 2.06-3.43, respectively; P < 0.01).

CONCLUSIONS

Hyponatremia is a common complication in hospitalized older patients and is caused mainly by respiratory diseases, tumors, and cardiovascular diseases. Given the correlation between the degree of hyponatremia and prognosis, the early and accurate identification and treatment of this condition can reduce the associated morbidity and mortality.

Prevalence of mild hyponatremia and its association with falls in older adults admitted to an emergency geriatric medicine unit (the MUPA unit)

Background

Hyponatremia is the most common electrolyte disorder in older adults and it can increase morbidity and mortality. Approximately one in three older adults fall each year; mild chronic hyponatremia can predispose this group to injurious falls and fractures and serum levels of sodium can also influence bone health. Little is known regarding the association between mild chronic hyponatremia and injurious fall prevalence in elderly patients admitted to the Emergency Department (ED). Therefore, the present study investigated the link between mild hyponatremia and the risk of injurious falls in elderly patients admitted to the Emergency Geriatric Medicine Unit (The MUPA Unit).

Methods

This cross-sectional study was conducted over 4 months and included patients ≥75 years of age who were admitted to the MUPA Unit of University Hospital Center of Limoges (France). Sociodemographic factors, fall events, comorbidities, medications, and sodium levels were assessed (hyponatremia was considered as sodium level < 136 mEq/L). Additionally, the short Comprehensive Geriatric Assessment (short-CGA), the Frailty score on the Short Emergency Geriatric Assessment (SEGA), and the Katz Activity of Daily Living (ADL) scale were administered.

Results

Of the 696 cases included in the final analysis, the mean age was 86.1 ± 5.6 years and 63.1% were female. The prevalence of falls was 27.9% (95% confidence interval [CI]: 24.6–31.2%) and that of mild hyponatremia was 15.9% (95% CI: 13.2–18.6%). The prevalence rate of mild hyponatremia was 13.2% (95% CI: 10.1–16.3%) in patients without falls and 26.1% (95% CI: 19.8–32.4%) in patients admitted for falls. Mild hyponatremia was significantly associated with falls (P < 0.001) and the adjusted odds ratio (OR) was 3.02 (95% CI: 1.84–4.96).

Conclusions

Because mild hyponatremia might be a risk factor for injurious falls and ED admission, determination of sodium levels during basic biomarker assessment on ED admission could be an important component of fall prevention strategies for the elderly.

Syndrome of inappropriate antidiuretic hormone secretion and Leser-Trélat syndrome as uncommon paraneoplastic manifestations of renal malignancy - a geriatric experience: a case report

Background

Leser–Trélat syndrome, which manifests as eruptive multiple seborrheic keratoses, is a rare paraneoplastic sign. Hyponatremia in the elderly population is an often overlooked but potentially sinister biochemical abnormality. Cancer-related causes of hyponatremia include syndrome of inappropriate antidiuretic hormone secretion, cerebral or renal salt wasting, and adrenal dysfunction. We report a case of an elderly man who presented with both syndrome of inappropriate antidiuretic hormone secretion and Leser–Trélat syndrome, and was eventually found to have renal malignancy.

Case presentation

A 74-year-old indigenous Malaysian man with underlying chronic kidney disease presented with recurrent admissions for hyponatremia with parameters indicative of syndrome of inappropriate antidiuretic hormone secretion, constitutional symptoms, and diffuse skin lesions suggestive of multiple seborrheic keratoses. A radiological workup revealed metastatic renal cell carcinoma with evidence of metastasis to the brain, adrenal glands, bone, and lungs.

Conclusions

To the best of our knowledge, renal malignancy presenting as syndrome of inappropriate antidiuretic hormone secretion and Leser–Trélat concurrently is rare. The causes of hyponatremia in the elderly, approach to investigation, and value as a poor prognostic marker in malignancy are highlighted. We also discuss Leser–Trélat syndrome, its pathophysiology, and its possible implications on clinical practice.

Duloxetine and Angiotensin II Receptor Blocker Combination Potentially Induce Severe Hyponatremia in an Elderly Woman

We encountered a case of syndrome of inappropriate antidiuretic hormone secretion (SIADH) caused by duloxetine, serotonin and norepinephrine reuptake inhibitor (SNRI). A 74-year-old woman complaining of severe lethargy was transferred to our emergency department. Her serum sodium level was 109 mEq/L. Plasma hypo-osmolality with urine normo-osmolality was observed, indicating SIADH. Her essential hypertension had long been treated with telmisartan, and she had just started duloxetine 20 mg/day for chronic musculoskeletal pain 4 days prior to admission. On prescribing duloxetine in the primary care setting, clinicians should be aware of the possibility of duloxetine-induced hyponatremia, particularly in combination with telmisartan.

Chronic idiopathic hyponatremia in an elderly patient due to inappropriate antidiuretic hormone secretion (SIADH) syndrome

INTRODUCTION

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a disorder which is characterized by the inability to suppress the secretion of antidiuretic hormone (ADH), leading to impaired water excretion and hyponatremia. The syndrome should be suspected in any patient with hyponatremia, hypo-osmolality and a urine osmolality >100 mOsm/kg, while urine sodium concentration is above 40 mEq/L.

CASE DESCRIPTION

Herein, we present an 84-year-old female patient with chronic idiopathic hyponatremia due to SIADH. Her laboratory tests showed hyponatremia with serum sodium of 120 mEq/L, while urine sodium concentration was 83 mEq/L. Measured serum osmolality was 255 mOsm/kg and urinary osmolality 130 mOsm/kg. In addition to these, her serum glucose, potassium, uric acid, renal, and liver functions were normal, and there were no acid-base disorders. The patient's adrenal function (cortisol, adrenocorticotropic hormone, renin, and aldosterone) showed no abnormalities, as well as her thyroid function.

DISCUSSION

The patient suffered from chronic idiopathic hyponatremia and osteoporosis, which often coexists in patients with chronic idiopathic SIADH and was treated with alendronate/cholecalciferol. The scenario of the presence of SIADH was further strengthened by the fact that hyponatremia did not improve after isotonic normal saline administration, but only with fluid restriction.  HIPPOKRATIA 2019, 23(1): 42-44.

Hyponatremia: Prevalence and characteristics in internal medicine patients in southeast of China

To determine the incidence, clinical features, etiology, risk factors, and mortality in internal medicine patients with hyponatremia (P-Na).A prospective survey was conducted in patients with P-Na, diagnosed at admission in an Internal Medicine Department. 692 patients were then selected and subsequently divided into 3 groups based on the severity of P-Na. Multivariate linear regression analysis was used to explore the factors associated with levels of P-Na.The prevalence of P-Na was 3.37%. Euvolemia P-Na was the predominant subtype in 3 types of P-Na (49.42%). Gastrointestinal and neurological manifestations were common hyponatremic symptoms. The leading 5 underlying diagnoses were chest infection (31.94%), malignancy (10.84%), cardiac disease (6.36%), liver cirrhosis (6.07%), and neurological disease (5.20%). Moderate and severe P-Na had higher mortalities than mild P-Na (P <.05). For the levels of serum Na, Age, and serum Cl were positively correlated while serum K, blood urea nitrogen (BUN), and Glu were negatively correlated (P <.05).P-Na is common in internal medicine and accompanied by other electrolyte disturbances, various symptoms/diagnoses, and increased mortalities with decreasing Na, which requires special attention in clinical practice.

Hyponatremia, falls and bone fractures: A systematic review and meta-analysis

OBJECTIVE

To perform a meta-analysis based on published studies that compared falls and bone fractures between patients with and without hyponatremia.

CONTEXT

There is evidence suggesting that hyponatremia is associated with an increased risk of falls and bone fractures.

DESIGN

An extensive Medline, Embase and Cochrane search was performed to retrieve all studies published up to, 30 April 2017, using the following words: "hyponatremia" or "hyponatraemia" AND "falls" and "bone fractures." A meta-analysis was performed including all studies comparing falls and bone fractures in subjects with or without hyponatremia.

PATIENTS AND RESULTS

Of 216 retrieved articles, 15 studies satisfied inclusion criteria encompassing a total of 51 879 patients, of whom 2329 were hyponatremic. Across all studies, hyponatremia was associated with a significantly increased risk of falls (MH-OR = 2.14[1.71; 2.67]. This result was confirmed when only hospitalized patients were considered (MH-OR = 2.44 [1.97; 3.02]). A meta-regression analysis showed that the hyponatremia-related risk of falls was higher in those studies considering a lower serum [Na+ ] cut-off to define hyponatremia. Interestingly, the estimated risk of falls related to hyponatremia was already significantly higher when a serum [Na+ ] cut-off of 135 mmol/L was considered (MH-OR = 1.26[1.23;1.29]). The presence of hyponatremia was also associated with a higher risk of fractures, particularly hip fractures (MH-OR = 2.00[1.43;2.81]).

CONCLUSIONS

This study confirms that hyponatremia is associated with an increased risk of falls and bone fractures. The clinical, social and economic relevance of such association is strengthened by the increased incidence of hyponatremia in older people.

Low serum sodium levels at hospital admission: Outcomes among 2.3 million hospitalized patients

Background

Hyponatremia is the most common electrolyte disorder among hospitalized patients. Controversies still exist over the relationship between hyponatremia and outcomes of hospitalized patients.

Methods

To analyze the association of low serum sodium levels at hospital admission with in-hospital mortality and patient disposition and to compare the distribution of the risk of death associated with hyponatremia across the lifespan of hospitalized patients, we conducted an observational study of 2.3 million patients using data extracted from the Cerner Health Facts database between 2000 and 2014. Logistic regression models were used in the analyses.

Results

At hospital admission 14.4% of hospitalized patients had serum sodium levels [Na] <135 mEq/L. In adjusted multinomial logistic regression analysis, we found that the risk of in-hospital mortality significantly increases for [Na] levels < 135 or ≥143 to ≤145 mEq/L compared to the reference interval of 140 to <143 mEq/L (p<0.001). We observed similar trends for the relationship between [Na] levels and discharge to hospice or to a nursing facility. We demonstrated that younger age groups (18 to <45, 45 to <65) had a higher risk of in-hospital mortality compared to older age groups (65 to <75, ≥75) for [Na] levels <130 mEq/L or 143 to ≤145 mEq/L (p<0.001).

Conclusions

Hyponatremia is common among hospitalized patients and is significantly associated with in-hospital mortality, discharge to hospice or to a nursing facility. The risk of death and other outcomes was more evident for [Na] <135 mEq/L. The mortality associated with low [Na] was significantly higher in younger versus older patients.

Elevated High-Density Lipoprotein Cholesterol Is Associated with Hyponatremia in Hypertensive Patients

BACKGROUND

Recently, the Systolic Blood Pressure Intervention Trial (SPRINT) showed that intensive lowering of systolic blood pressure is beneficial, but is associated with more adverse events. Hyponatremia was notably more frequent in the intensive treatment group. Investigating its risk factors is crucial for preventing this complication. Our objective in this study was to identify risk factors for hyponatremia in the adult population.

METHODS

We investigated the baseline demographic, clinical, and laboratory data from the 9361 participants of SPRINT to identify the best predictors of hyponatremia (serum sodium ≤130 mEq/L), and adverse events, which could be attributed to hyponatremia, using machine learning and multivariable Cox proportional hazards models. We confirmed our results in the independent National Health and Nutrition Examination Survey (NHANES) cohort between the years 2005 and 2010 (16,501 participants).

RESULTS

Elevated baseline high-density lipoprotein cholesterol (HDL-C) was a strong predictor of future hyponatremia. Multivariable Cox regression showed hyponatremia events to be significantly increased for SPRINT participants with baseline HDL-C levels in the highest quintile (hazard ratio [HR] 2.8; 95% confidence interval [CI], 2.2-3.7; P <.001), and were also associated with treatment-related serious adverse events (HR 1.6; 95% CI, 1.3-2.1; P <.001). We confirmed the association between HDL-C and hyponatremia in the NHANES cohort (HR 2.5; 95% CI, 1.7-3.7; P <.001).

CONCLUSIONS

Elevated HDL-C (≥62 mg/dL) is a risk factor for hyponatremia. Thus, hypertensive patients with elevated HDL-C should be closely monitored for hyponatremia when treated for hypertension.

Hypertrophic Pachymeningitis and the Syndrome of Inappropriate Antidiuretic Hormone Secretion: Coincidence or Cause?

OBJECTIVE

To investigate a potential cause of the syndrome of inappropriate antidiuretic hormone secretion (SIADH).

CLINICAL PRESENTATION AND INTERVENTION

A 70-year-old female patient had nausea and collapsed. Although euvolemic, pathological laboratory findings showed hyponatremia and hypoosmolality, and cerebral magnetic resonance imaging showed hypertrophic pachymeningitis. Secondary hypertrophic pachymeningitis was excluded. Other nonneurological reasons for SIADH were also excluded. Moderate fluid restriction restored an almost normal serum osmolality and sodium.

CONCLUSION

This case of SIADH was conservatively treated with moderate fluid restriction that almost restored normal serum osmolality and sodium levels.