A case-control study of hyponatraemia as an independent risk factor for inpatient mortality

Low Prevalence of Clinically Significant Hyponatremia following Cranial Vault Reconstruction for Single-Suture Craniosynostosis

BACKGROUND

Patients are commonly monitored for hyponatremia after intracranial procedures, yet the prevalence of hyponatremia after cranial vault reconstruction (CVR) remains unclear. The purpose of this study is to define the prevalence, risk factors, and complications of hyponatremia after CVR to optimize postoperative sodium surveillance protocols.

METHODS

Patients with nonsyndromic, single-suture craniosynostosis who underwent primary CVR between 2009 and 2020 at Michigan Medicine were included (n = 231). Demographic, intraoperative, and postoperative characteristics were compared by postoperative hyponatremia status at P < 0.05 significance. Hyponatremia was defined as mild (<135 mEq/L), moderate (<130 mEq/L), or severe (<125 mEq/L) based on the lowest postoperative laboratory draw.

RESULTS

Twenty-three patients (10.0%) developed mild postoperative hyponatremia. No patient developed moderate or severe postoperative hyponatremia. On multivariable regression, decreased preoperative sodium level (P = 0.03) and decreased preoperative weight (P = 0.02) were significantly associated with mild postoperative hyponatremia. No patient developed complications or required hospital readmission because of hyponatremia.

CONCLUSIONS

This large retrospective cohort study of patients with nonsyndromic single-suture craniosynostosis demonstrated a 10% prevalence of mild, clinically inconsequential hyponatremia and 0% prevalence of moderate or severe, clinically significant hyponatremia after primary CVR. Patients with low preoperative sodium level or weight were at increased risk for developing mild postoperative hyponatremia. The results suggest that patients with preoperative sodium greater than 140 mEq/L or preoperative weight greater than 10 kg may be candidates for limited postoperative sodium surveillance; however, future prospective studies are warranted before implementation.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Predictive value of hyponatremia for short-term mortality in supratentorial spontaneous intracerebral hemorrhage: a single center study

Background

Hyponatremia is a common electrolyte disturbance in patients with neurological disease; however, its predictive role for outcome in patients with supratentorial spontaneous intracerebral hemorrhage (sICH) is controversial. This study aims to explore the association between hyponatremia within 7 days after bleeding and 90-day mortality in patients with supratentorial sICH.

Methods

A retrospective analysis was conducted at our institution. Patients with sICH meeting the inclusion criteria were enrolled in this study. Multivariate regression analyses were performed to determine the predictive value of hyponatremia (serum sodium <135 mmol/L) for 90-day mortality and functional outcome. Subgroup analysis was performed based on the degree and duration of hyponatremia and therapeutic strategies. The Spearman correlation test was performed to explore the relationship between hyponatremia severity and duration with variables in a multivariate regression model. Kaplan-Meier curve was depicted to reveal the relationship between hyponatremia and mortality. The receiver operating characteristic (ROC) curve was plotted to show the diagnostic effect of the minimum concentration of serum sodium (sodiummin) on 90-day mortality.

Results

A total of 960 patients were enrolled, 19.6% (188) of whom were patients with hyponatremia and 26.0% (250) had 90-day mortality. The incidence of hyponatremia was roughly 2.5 times in non-survivors compared with survivors (34.8% vs. 14.2%). Multivariate regression analysis revealed that hyponatremia was the independent predictor of 90-day mortality (OR 2.763, 95%CI 1.836-4.157) and adverse outcome (OR 3.579, 95%CI 2.332-6.780). Subgroup analysis indicated an increased trend in mortality risk with both duration (more or less than 48 h) and severity of hyponatremia (mild, moderate, and severe) and confirmed the predictive value of hyponatremia for mortality in patients undergoing surgical intervention (external ventricular drainage, craniotomy, and decompressive craniectomy; all p < 0.05). The Spearman correlation test indicated no moderate or strong relationship between hyponatremia severity and duration with other variables in the multivariate model (all |rs| < 0.4). The ROC curve suggested the moderate diagnostic performance of sodiummin for mortality in both general patients and subgroups of therapeutic method patients (AUC from 0.6475 to 0.7384).

Conclusion

Hyponatremia occurring in the first 7 days after bleeding is an independent predictor of 90-day morality and adverse outcome. Rigorous electrolyte scrutiny in patients treated surgically is required.

Frequency of dysnatremia in patients admitted with COVID-19 infection and its prognostic implication

OBJECTIVE

We aimed to investigate the frequency of dysnatremia among patients admitted with COVID-19 infection and its association with inpatient mortality.

METHODS

This retrospective longitudinal study was conducted for 12 weeks. Serum sodium levels were recorded at admission, during the hospital stay, and within 48 hours of discharge or death. Logistic regression was used to determine the predictors of mortality.

RESULTS

This study included 574 patients (69.7% men, age 55.6 ± 14.4 years). On admission, mean sodium was 135.9 ± 6.4 mEq/L; 39% had hyponatremia and 4.7% had hypernatremia. During admission, hypernatremia increased to 18.8%; maximum sodium in patients who survived was 140.6 ± 5.0 mEq/L versus 151.0 ± 9.9 mEq/L in those who died. The final sodium was 145.4 ± 9.4 mEq/L in patients who died versus 137.7 ± 3.7 mEq/L in those who survived (odds ratio [OR]: 1.22, 95% confidence interval [CI]: 1.13-1.32). Other predictors of mortality included ischemic heart disease (OR: 3.65, 95% CI: 1.39-9.61), acute kidney injury (OR: 6.07, 95% CI: 2.39-15.42), invasive ventilation (OR: 28.4, 95% CI: 11.14-72.40), and length of stay (OR: 0.91, 95% CI: 0.86-0.97).

CONCLUSION

Hypernatremia was frequently observed in patients who were critically ill and died and may be considered a predictor of mortality in COVID-19 infection.

Nomogram Prediction Model of Hypernatremia on Mortality in Critically Ill Patients

Objective

To investigate the value of hypernatremia in the intensive care unit (ICU) for the risk prediction of mortality in severe patients.

Methods

Clinical data of critically ill patients admitted to the ICU of Beijing Friendship Hospital, were collected for retrospective analysis. Univariate and multivariate logistic regression analyses were employed to analyze the influencing factors. Nomograms predicting the mortality were constructed with R software and validated with repeated sampling.

Results

A total of 442 cases were eligible for this study. Hypernatremia within 48 hours of ICU admission, change in sodium concentration (CNa+) within 48 hours, septic shock, APACHE II score, hyperlactatemia within 48 hours, use of continuous renal replacement therapy (CRRT) within 48 hours, and the use of mechanical ventilation (MV) within 48 hours of ICU admission were all identified as independent risk factors for death within 28 days of ICU admission. These predictors were included in a nomogram of 28-day mortality in severe patients, which was constructed using R software.

Conclusion

The nomogram could predict the individualized risk of 28-day mortality based on the above factors. The model has better discrimination and accuracy and has high clinical application value.

MANAGEMENT OF ENDOCRINE DISEASE: Dysnatraemia in COVID-19: prevalence, prognostic impact, pathophysiology, and management

This review examines the prevalence, aetiology, pathophysiology, prognostic value, and investigation of dysnatraemia in hospitalised COVID-19 patients, taking into account all relevant studies published in PubMed and Cochrane Library studies until March 2021. Hyponatraemia is commonly observed in patients with bacterial pneumonia and is an independent predictor for excess mortality and morbidity. However, it remains unknown whether this association applies to coronavirus disease-2019 (COVID-19). Several studies reported a 20-35% prevalence for hyponatraemia and 2-5% for hypernatraemia in patients admitted with COVID-19. In addition, hyponatraemia on admission was a risk factor for progression to severe disease, being associated with an increased likelihood for the need for invasive mechanical ventilation, with an odds ratio (OR) of 1.83-3.30. Hyponatraemia seems to be an independent risk factor for mortality, with an OR of 1.40-1.50 compared to normonatraemia, while hypernatraemia is related to even worse outcomes than hyponatraemia. Furthermore, preliminary data show an inverse association between serum sodium and interleukin-6 levels, suggesting that hyponatraemia might be used as a surrogate marker for the risk of a cytokine storm and the need for treatment with interleukin antagonists. In conclusion, dysnatraemia is common and carries a poor prognosis in COVID-19 patients, indicating that it may play a future role in risk stratification and individualising therapy.

Dysnatremia is a Predictor for Morbidity and Mortality in Hospitalized Patients with COVID-19

CONTEXT

Dysnatremia is an independent predictor of mortality in patients with bacterial pneumonia. There is paucity of data about the incidence and prognostic impact of abnormal sodium concentration in patients with coronavirus disease 2019 (COVID-19).

OBJECTIVE

This work aimed to examine the association of serum sodium during hospitalization with key clinical outcomes, including mortality, need for advanced respiratory support and acute kidney injury (AKI), and to explore the role of serum sodium as a marker of inflammatory response in COVID-19.

METHODS

This retrospective longitudinal cohort study, including all adult patients who presented with COVID-19 to 2 hospitals in London over an 8-week period, evaluated the association of dysnatremia (serum sodium < 135 or > 145 mmol/L, hyponatremia, and hypernatremia, respectively) at several time points with inpatient mortality, need for advanced ventilatory support, and AKI.

RESULTS

The study included 488 patients (median age, 68 years). At presentation, 24.6% of patients were hyponatremic, mainly due to hypovolemia, and 5.3% hypernatremic. Hypernatremia 2 days after admission and exposure to hypernatremia at any time point during hospitalization were associated with a 2.34-fold (95% CI, 1.08-5.05; P = .0014) and 3.05-fold (95% CI, 1.69-5.49; P < .0001) increased risk of death, respectively, compared to normonatremia. Hyponatremia at admission was linked with a 2.18-fold increase in the likelihood of needing ventilatory support (95% CI, 1.34-3.45, P = .0011). Hyponatremia was not a risk factor for in-hospital mortality, except for the subgroup of patients with hypovolemic hyponatremia. Sodium values were not associated with the risk for AKI and length of hospital stay.

CONCLUSION

Abnormal sodium levels during hospitalization are risk factors for poor prognosis, with hypernatremia and hyponatremia being associated with a greater risk of death and respiratory failure, respectively. Serum sodium values could be used for risk stratification in patients with COVID-19.

Prognostic Value of Hyponatremia During Acute Painful Episodes in Sickle Cell Disease

BACKGROUND

Low plasma sodium concentration has been recognized as a prognostic factor in several disorders but never evaluated in sickle cell disease. The present study evaluates its value at admission to predict a complication in adult patients with sickle cell disease hospitalized for an initially uncomplicated acute painful episode.

METHODS

The primary outcome of this retrospective study, performed between 2010 and 2015 in a French referral center for sickle cell disease, was a composite criterion including acute chest syndrome, intensive care unit transfer, red blood cell transfusion or inpatient death. Analyses were adjusted for age, sex, hemoglobin genotype and concentration, lactate dehydrogenase (LDH) concentration, and white blood cell count.

RESULTS

We included 1218 stays (406 patients). No inpatient death occurred during the study period. Hyponatremia (plasma sodium ≤135 mmol/L) at admission in the center was associated with the primary outcome (adjusted odds ratio [OR] 1.95, 95% confidence interval [CI] 1.3-2.91, P = 0.001), with acute chest syndrome (OR 1.95 [95% CI 1.2-3.17, P = 0.008]), and red blood cell transfusion (OR 2.71 [95% CI 1.58-4.65, P <0.001]) but not significantly with intensive care unit transfer (OR 1.83 [95% CI 0.94-3.79, P = 0.074]). Adjusted mean length of stay was longer by 1.1 days (95% CI 0.5-1.6, P <0.001) in patients with hyponatremia at admission.

CONCLUSIONS

Hyponatremia at admission in the medical department for an acute painful episode is a strong and independent prognostic factor of unfavorable outcome and, notably, acute chest syndrome. It could help targeting patients who may benefit from closer monitoring.

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.

Risk Factors for Recurrent Hematoma After Surgery for Acute Traumatic Subdural Hematoma

OBJECTIVE

The development of postcraniotomy hematoma (PCH) after surgery for acute traumatic subdural hematoma (aSDH) has been associated with an increased risk of a poor outcome. The risk factors contributing to PCH remain poorly understood. Our aim was to study the potential risk factors for PCH in a consecutive series of surgically evacuated patients with aSDH.

METHODS

A total of 132 patients with aSDH treated at Turku University Hospital (Turku, Finland) from 2008 to 2012 were enrolled in the present retrospective cohort study. The demographic, clinical, laboratory, and imaging data were collected from the medical records. A comprehensive analysis of the data using 6 different univariate methods, including machine learning and multivariate analyses, was conducted to identify the factors related to PCH.

RESULTS

The incidence of PCH after primary surgery for traumatic aSDH was 10.6%. The patients experiencing PCH were younger (P = 0.04). No difference was found in the use of anticoagulant or antiplatelet medication for the patients with and without PCH. Multivariate analyses identified alcohol inebriation at the time of injury (odds ratio [OR], 12.67; P = 0.041) and hypocapnia (OR, 26.09; P = 0.003) as independent risk factors for PCH. The patients with PCH had had hyponatremia (OR, 0.08; P = 0.018) less often, and their maximal systolic blood pressure was lower (OR, 0.94; P = 0.009). The area under the curve for the multivariate model was 0.96 (P = 0.049), with a Youden index of 0.88.

CONCLUSIONS

The results suggest that alcohol inebriation at the time of injury and hypocapnia during hospitalization are risk factors for the development of PCH.

Poverty as an independent risk factor for in-hospital mortality in community-acquired pneumonia: A study in a developing country population

BACKGROUND

Community-acquired pneumonia (CAP) is one of the most severe lower respiratory tract infections with a high in-hospital mortality. The aim of this study was to investigate the socioeconomic and medical risk factors affecting the prognosis of acute pneumonia. The results of this study can mention the value of socioeconomic backgrounds like poverty and illiteracy in clinical practice, even in a well-known biological phenomenon (eg acute pneumonia).

METHODS

In this cross-sectional study, all admitted patients to a tertiary teaching hospital with a diagnosis of community acquired pneumonia in a 12-month period were enrolled. Socioeconomic and demographic characteristics, underlying conditions, clinical manifestations and para-clinical test results at admission registered prospectively. A logistic regression model was conducted using in-hospital mortality as the dependent variable.

RESULTS

A total of 621 patients was included in this study. Among them, 47 patients (7.6%) died during the hospitalisation period. In multiple logistic regression analysis, pleural effusion, a higher CURB-65 score, hyponatremia, hyperglycaemia and poverty (being in the lower economic class) were identified as independent risk factors for in-hospital mortality in community-acquired pneumonia.

CONCLUSION

Numerous factors can influence the prognosis of CAP. In addition to the CURB-65 score and some other medical risk factors, socioeconomic backgrounds can also affect the early outcome in CAP. In this study, being in the lower economic class (as an indicator of poverty) is interpreted as an independent risk factor for a poor prognosis in CAP.

Mortality rates are lower in SIAD, than in hypervolaemic or hypovolaemic hyponatraemia: Results of a prospective observational study

OBJECTIVE

Hyponatraemia is associated with increased mortality, but the mortality associated specifically with SIAD is not known. We hypothesized that mortality in SIAD was elevated, but that it was less than in hypervolaemic (HEN) or hypovolaemic (HON) hyponatraemia.

DESIGN

Mortality rates are presented as risk ratios (RR),with 95% confidence intervals (CI), and compared to normonatraemic controls (NN).

METHODS

Prospective, single centre, noninterventional study of all patients with hyponatraemia (≤130 mmol/L) admitted to hospital.

RESULTS

A total of 1323 admissions with hyponatraemia were prospectively evaluated and 1136 contemporaneous NN controls. 431(32.6%) hyponatraemic patients had HON, 573(43.3%) had SIAD and 275(20.8%) patients had HEN. In patient mortality was higher in hyponatraemia than NN (9.1% vs 3.3%, P<.0001). The RRs for in-hospital mortality compared to NN were: SIAD, 1.76 (95% CI 1.08-2.8, P=.02), HON 2.77 (95% CI 1.8-4.3, P<.0001) and HEN, 4.9 (95% CI 3.2-7.4, P<.0001). The mortality rate was higher in HEN (RR 2.85; 95% CI 1.86-4.37, P<.0001) and in HON, (RR 1.6; 95% CI 1.04-2.52; P=.03), when compared to SIAD. The Charlson Comorbidity Index was lower in SIAD than in eunatraemic patients (P<.0001). 9/121(7.4%) patients died with plasma sodium <125 mmol/L and 4(3.3%) with plasma sodium <120 mmol/L. However, 69/121(57%) patients died with a plasma sodium above 133 mmol/L.

CONCLUSIONS

We confirmed higher all-cause mortality in hyponatraemia than in NN. Mortality was higher in SIAD than in normonatraemia and was not explained on the basis of co-morbidities. Mortality was higher in HON and HEN than in SIAD. Mortality rates reported for all-cause hyponatraemia in the medical literature are not applicable to SIAD.

Prevalence of Hyponatremia and Its Associated Morbimortality in Hospitalized Patients Receiving Parenteral Nutrition

Background: The objective of the study was to determine the prevalence of hyponatremia (HN) and its associated morbimortality in hospitalized patients receiving parenteral nutrition (PN). Methods: A retrospective study including 222 patients receiving total PN (parenteral nutrition group [PNG]) over a 7-month period in a tertiary hospital and 176 matched to 179 control subjects without PN (control subjects group [CSG]). Demographic data, Charlson Comorbidity Index (CCI), date of HN detection-(serum sodium or SNa <135 mmol/L)-intrahospital mortality, and hospital length-of-stay (LOS) were registered. In the PNG, body mass index (BMI) and SNa before, during, and after PN were recorded. Results: HN was more prevalent in the PNG: 52.8 vs. 35.8% (p = 0.001), and independent of age, gender, or CCI (OR 1.8 [95% CI 1.1-2.8], p = 0.006). In patients on PN, sustained HN (75% of all intraindividual SNa <135 mmol/L) was associated with a higher mortality rate independent of age, gender, CCI, or BMI (OR 7.38 [95% CI 1.07-50.8], p = 0.042). The absence of HN in PN patients was associated with a shorter hospital LOS (<30 days) and was independent of other comorbidities (OR 3.89 [95% CI 2.11-7.18], p = 0.001). Conclusions: HN is more prevalent in patients on PN. Sustained HN is associated with a higher intrahospital mortality rate. Absence of HN is associated with a shorter hospital LOS.

Prognostic impact of hyponatremia occurring at various time points during hospitalization on mortality in patients with acute myocardial infarction

We investigated the incidence and prognostic impact of hyponatremia occurring at various time points during hospitalization on long-term mortality in acute myocardial infarction (AMI) survivors. We retrospectively studied 1863 patients diagnosed with AMI. Baseline, nadir, and discharge sodium levels during hospitalization were recorded and analyzed. Hyponatremia was defined as a serum sodium level <135 mEq/L. On the basis of baseline, nadir, and discharge sodium levels during hospitalization, hyponatremia was diagnosed in 309 (16.6%), 518 (27.8%), and 147 (7.9%) patients, respectively. In a multivariate Cox-proportional regression analysis, discharge sodium level had the strongest significant relationship with long-term mortality (hazard ratio [HR] as continuous variable = 1.06, 95% confidence interval [CI]: 1.01-1.11, P = .026; HR as categorical variable = 1.71; 95% CI: 1.06-2.75; P = .028), but baseline and nadir sodium had no prognostic impact on long-term mortality after adjustment. The serum sodium level and incidence of hyponatremia varied at different time points during hospitalization. In addition, the association between sodium level and long-term mortality differed at these various time points. The discharge sodium level, among the various time points, seems the best predictor of long-term mortality in AMI survivors.

Improving care and outcomes of inpatients with syndrome of inappropriate antidiuresis (SIAD): a prospective intervention study of intensive endocrine input vs. routine care

PURPOSE

The syndrome of inappropriate antidiuresis is often undertreated with most patients discharged with persistent hyponatraemia. This study tested the hypothesis that an endocrine input is superior to routine care in correcting hyponatraemia and can improve patient outcomes.

METHODS

This single-centre prospective-controlled intervention study included inpatients admitted at a UK teaching hospital, with serum sodium ≤ 127 mmol/l, due to syndrome of inappropriate antidiuresis over a 6-month period. The prospective intervention group (18 subjects with mean serum sodium 120.7 mmol/l) received prompt endocrine input, while the historical control group (23 patients with mean serum sodium 124.1 mmol/l) received routine care. The time needed for serum sodium increase ≥ 5 mmol/l was the primary endpoint.

RESULTS

The intervention group achieved serum sodium rise by ≥5 mmol/l in 3.5 vs. 7.1 days in the control group (P = 0.005). In the intervention group, the mean total serum sodium increase was 12 mmol/l with only 5.8 % of patients discharged with serum sodium < 130 vs. 6.3 mmol/l increase (P < 0.001) and 42.1 % of the subjects discharged with serum sodium < 130 mmol/l in the control group (P = 0.012). The mean length of hospital stay in the intervention group (10.9 days) was significantly shorter than in the control group (14.5 days; P = 0.004).The inpatient mortality rate was 5.5 % in intervention arm vs. 17.4 % in control arm, but this difference was not statistically significant.

CONCLUSIONS

Since the endocrine input improved time for correction of hyponatraemia and shortened length of hospitalisation, widespread provision of endocrine input should be considered.

SIAD: practical recommendations for diagnosis and management

Hyponatremia is the commonest electrolyte disturbance encountered in hospitalized patients, and the syndrome of inappropriate antidiuresis (SIAD) is the most frequent underlying disorder. There is a well-recognized relationship between hyponatremia and increased morbidity and mortality. Therefore, to provide appropriate treatment is critical to improve the clinical outcome related to SIAD-hyponatremia. There have been important advances in the treatment of SIAD over the last decade, leading to the publication of several clinical guidelines. In particular, the introduction of the vasopressin-2 receptor antagonists provides a potent pharmacological tool to target the underlying pathophysiology of SIAD. The evidence base recommendations of the available therapies for SIAD are discussed in this study. Fluid restriction is considered the first-line therapy by the recent published guidelines, but it is certainly ineffective or unfeasible in many patients with SIAD. We discuss a number of relevant points to the use of fluid restriction in this study, including the lack of good evidence-based recommendations to support its use. Conversely, the clinical efficacy of oral tolvaptan in SIAD supported by good quality randomized, placebo controlled, clinical trials. However, the cost of the therapy and the need for long-term safety data may limit its widespread use. Finally, new recommendations for the management of acute hyponatremia with a focus on the use of bolus therapy with 3 % hypertonic sodium chloride are described in this study.

Real-life experience of tolvaptan use in the treatment of severe hyponatraemia due to syndrome of inappropriate antidiuretic hormone secretion

OBJECTIVE

European guidelines do not recommend tolvaptan for treatment of syndrome of inappropriate antidiuretic hormone secretion (SIADH), principally owing to concerns about risk of overly rapid correction of hyponatraemia. This study evaluated the real-life effectiveness and safety of tolvaptan.

DESIGN

Consecutive case series.

PATIENTS

Inpatients treated with tolvaptan for SIADH in 2 UK hospitals over a 3-year period.

MEASUREMENTS

The primary outcome measures were serum sodium (sNa) correction at 24 and 48 h after tolvaptan therapy.

RESULTS

This case series included 61 patients aged 74·4 ± 15·3 years with (mean ± SD) sNa 119·9 ± 5·5 mmol/l. The mean sNa increase 24 h after tolvaptan initiation was 9 ± 3·9 mmol/l. Excessive correction of hyponatraemia was observed in 23% of patients with all these patients having baseline sNa <125 mmol/l, but no cases of osmotic demyelination syndrome were recorded. At the end of tolvaptan therapy, sNa increase was 13·5 ± 5·9 mmol/l with 96·7% of patients having sNa increase ≥5 mmol/l in 48 h. There was a negative significant correlation (P = 0·012) between baseline sNa and 24-h change; for every 1 mmol/l reduction in baseline value, sNa increased by an additional 0·23 mmol/l (95% CI 0·05-0·41).

CONCLUSIONS

Tolvaptan is effective in correcting hyponatraemia. Without rigorous electrolyte monitoring, tolvaptan carries a significant risk of overly rapid sodium correction, especially in patients with starting sNa <125 mmol/l. Tolvaptan should be used with great caution under close electrolyte monitoring.

Diagnosis and treatment of hyponatraemia in neurosurgical patients

Hyponatraemia is the most common electrolyte imbalance in neurosurgical patients. Acute hyponatraemia is particularly common in neurosurgical patients after any type of brain insult, including brain tumours and their treatment, pituitary surgery, subarachnoid haemorrhage or traumatic brain injury. Acute hyponatraemia is an emergency condition, as it leads to cerebral oedema due to passive osmotic movement of water from the hypotonic plasma to the relatively hypertonic brain which ultimately is the cause of the symptoms associated with hyponatraemia. These include decreased level of consciousness, seizures, non-cardiogenic pulmonary oedema or transtentorial brain herniation. Prompt treatment is mandatory to prevent such complications, minimize permanent brain damage and therefore permit rapid recovery after brain insult. The infusion of 3% hypertonic saline is the treatment of choice with different rates of administration based on the severity of symptoms and the rate of drop in plasma sodium concentration. The pathophysiology of hyponatraemia in neurotrauma is multifactorial; although the syndrome of inappropriate antidiuresis (SIADH) and central adrenal insufficiency are the commonest causes encountered. Fluid restriction has historically been the classical treatment for SIADH, although it is relatively contraindicated in some neurosurgical patients such as those with subarachnoid haemorrhage. Furthermore, many cases admitted have acute onset hyponatraemia, who require hypertonic saline infusion. The recently developed vasopressin receptor 2 antagonist class of drug is a promising and effective tool but more evidence is needed in neurosurgical patients. Central adrenal insufficiency may also cause acute hyponatraemia in neurosurgical patients; this responds clinically and biochemically to hydrocortisone. The rare cerebral salt wasting syndrome is treated with large volume normal saline infusion. In this review, we summarize the current evidence based on the clinical presentation, causes and treatment of different types of hyponatraemia in neurosurgical patients.

Diagnosis and treatment of hyponatraemia

Hyponatraemia is the most common electrolyte abnormality encountered by physicians in the hospital setting. It is associated with increased mortality and length of hospital stay. However, the basis of the relationship of hyponatraemia with clinical outcome is not clear. Doubt remains as to whether the relationship is causal. It may reflect the association of two independent variables both of which are linked with disease severity. Serum sodium concentration is regulated through integrated neuro-humeral mechanisms that overlap with those regulating circulating volume. A mechanistic approach to the classification of hyponatraemia can support a framework for investigation and differential diagnosis based on urine osmolality and urine sodium concentration. Such a framework is more reliable than those based on the clinical assessment of volume status. In the emergency setting, the initial management of hyponatraemia is cause-independent. In other clinical contexts, a cause-specific approach is recommended. Over-rapid correction of serum sodium risks precipitating osmotic demyelination syndrome. Avoiding over-rapid correction is critical in any approach to patient care. Sodium is the major circulating cation and thus a key determinant of overall plasma osmolality. Serum sodium concentration is maintained within a tight physiological range over time, despite wide variation in both sodium and water intake. Hyponatraemia (serum sodium concentration <135 mmols/L) is the most common electrolyte disturbance in clinical practice. All clinicians should be aware of the scope and scale of the problem.

Hyponatremia predicts mortality after stroke

Background

Hyponatremia, the commonest electrolyte imbalance encountered in clinical practice, is associated with adverse outcomes. Despite this, understanding of the association between hyponatremia and stroke mortality outcome is limited.

Aims

To investigate the association between admission serum sodium and mortality at various time-points after stroke.

Methods

Cases of acute stroke admitted to Norfolk and Norwich University Hospital consecutively from January 2003 until June 2013 were included, with mortality outcomes ascertained until the end of December 2013. Odds ratios or hazards ratios for death were constructed for various time-points (within seven-days, 8-30 days, within one-year, and over full follow-up).

Results

There were 8540 participants included (47.4% male, mean age 77.3 (±12.0) years). Point prevalence of hypernatremia and hyponatremia were 3.3% and 13.8%, respectively. In fully adjusted models controlling for age, gender, prestroke modified Rankin score, stroke type, Oxford community stroke project class, and laboratory biochemical and hematological results, the odds ratio (up to one-year)/hazards ratio (for full follow-up) for the above time-points were 1.00, 1.11, 1.03, 1.05 for mild hyponatremia; 1.97, 0.78, 1.11, 1.2 for moderate hyponatremia; 3.31, 1.57, 2.45, 1.67 for severe hyponatremia; and 0.47, 1.23, 1.30, 1.10 for hypernatremia. When stratified by age groups, outcomes were poorer in younger hyponatremic patients (aged <75 years).

Conclusion

Hyponatremia is prevalent in acute stroke admissions and is independently associated with higher mortality in patients <75 years).

Multicentre study of investigation and management of inpatient hyponatraemia in the UK

Purpose

Hyponatraemia is associated with significant morbidity and mortality. The objectives of this study were to evaluate the investigation and management of hyponatraemia and to assess the use of different therapeutic modalities and their effectiveness in routine practice.

Study design

This multicentre, retrospective, observational study was conducted at three acute NHS Trusts in March 2013. A retrospective chart review was performed on the first 100 inpatients with serum sodium (sNa) ≤128 mmol/L during hospitalisation.

Results

One hundred patients (47 male, 53 female) with a mean±SD age of 71.3±15.4 years and nadir sNa of 123.4±4.3 mmol/L were included. Only 23/100 (23%) had measurements of paired serum and urine osmolality and sodium, while 31% had an assessment of adrenal reserve. The aetiology of hyponatraemia was unrecorded in 58% of cases. The mean length of hospital stay was 17.5 days with an inpatient mortality rate of 16%. At hospital discharge, 53/84 (63.1%) patients had persistent hyponatraemia, including 20/84 (23.8%) with sNa <130 mmol/L. Overall 37/100 (37%) patients did not have any treatment for hyponatraemia. Among 76 therapeutic episodes, the most commonly used treatment modalities were isotonic saline in 38/76 cases (50%) and fluid restriction in 16/76 (21.1%). Fluid restriction failed to increase sNa by >1 mmol/L/day in 8/10 (80%) cases compared with 4/26 (15.4%) for isotonic saline.

Conclusions

Underinvestigation and undertreatment of hyponatraemia is a common occurrence in UK clinical practice. Therefore, development of UK guidelines and introduction of electronic alerts for hyponatraemia should be considered to improve clinical practice.

Hyponatraemia in Emergency Medical Admissions-Outcomes and Costs

Healthcare systems in the developed world are struggling with the demand of emergency room presentations; the study of the factors driving such demand is of fundamental importance. From a database of all emergency medical admissions (66,933 episodes in 36,271 patients) to St James’ Hospital, Dublin, Ireland, over 12 years (2002 to 2013) we have explored the impact of hyponatraemia on outcomes (30 days in-hospital mortality, length of stay (LOS) and costs). Identified variables, including Acute Illness Severity, Charlson Co-Morbidity and Chronic Disabling Disease that proved predictive univariately were entered into a multivariable logistic regression model to predict the bivariate of 30 days in-hospital survival. A zero truncated Poisson regression model assessed LOS and episode costs and the incidence rate ratios were calculated. Hyponatraemia was present in 22.7% of episodes and 20.3% of patients. The 30 days in-hospital mortality rate for hyponatraemic patients was higher (15.9% vs. 6.9% p < 0.001) and the LOS longer (6.3 (95% CI 2.9, 12.2) vs. 4.0 (95% CI 1.5, 8.2) p < 0.001). Both parameters worsened with the severity of the initial sodium level. Hospital costs increased non-linearly with the severity of initial hyponatraemia. Hyponatraemia remained an independent predictor of 30 days in-hospital mortality, length of stay and costs in the multi-variable model.

Prognosis of hyponatremia in elderly patients with fragility fractures

BACKGROUND

Hyponatremia (serum sodium < 135 mmol/L) is the commonest electrolyte imbalance encountered in clinical practice. It is associated with multiple poor clinical outcomes including increased length of hospital stay, institutionalization and mortality. Prevalence of hyponatremia is higher in frail patient groups, and elderly patients with fragility fractures (EPFF) are particularly susceptible. This study aimed to establish the impact of hyponatremia on total length of inpatient stay (TLOS), need for inpatient rehabilitation and mortality in EPFF.

METHODS

Prospective observational study of consenting adults aged ≥ 65 years admitted with a fragility fracture to a university hospital between January 7, and April 4, 2013. Demographic and clinical data, length of hospital stay, discharge destination and any participant deaths were recorded. Prevalence of hyponatremia on admission and incidence of cases developing in hospital were reported. Basic demographic data and serum sodium results were included in multivariate linear regression models for TLOS. Difference in mortality rate and proportion of individuals discharged to inpatient rehabilitation between the hyponatremic and normonatremic group were tested using Chi-squared and Fisher's exact tests. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) were also calculated.

RESULTS

Of 212 cases, 127 (60%) EPFF were recruited (mean age 79 years, 78% female). Of those not recruited, 66 had incapacity to consent and 19 refused participation. Thirty-three cases of hyponatremia were identified; point prevalence on admission was 13.4% and a further 12.6% developed hyponatremia during admission. There were no statistically significant differences in patient characteristics between the hyponatremic and normonatremic group. Hyponatremic participants had a 66.7% increased time from admission to surgery (P = 0.014) and a 51.5% increased length of index hospital stay (P = 0.006). Factors independently associated with increased TLOS were age (P = 0.03) and drop in sodium during admission (P < 0.001). Mortality rate and proportion of participants discharged to inpatient rehabilitation were higher in the hyponatremic group (OR 4.2 (95% CI: 0.9 - 19.8) and 2.2 (95% CI: 0.9 - 5.1), respectively), but figures did not reach statistical significance.

CONCLUSIONS

Hyponatremia is highly prevalent in EPFF, seen in 33/127 cases (26%), and is associated with increased length of index hospital stay. Drop in serum sodium during admission was independently associated with increased TLOS.

Neurosurgical Hyponatremia

Hyponatremia is a frequent electrolyte imbalance in hospital inpatients. Acute onset hyponatremia is particularly common in patients who have undergone any type of brain insult, including traumatic brain injury, subarachnoid hemorrhage and brain tumors, and is a frequent complication of intracranial procedures. Acute hyponatremia is more clinically dangerous than chronic hyponatremia, as it creates an osmotic gradient between the brain and the plasma, which promotes the movement of water from the plasma into brain cells, causing cerebral edema and neurological compromise. Unless acute hyponatremia is corrected promptly and effectively, cerebral edema may manifest through impaired consciousness level, seizures, elevated intracranial pressure, and, potentially, death due to cerebral herniation. The pathophysiology of hyponatremia in neurotrauma is multifactorial, but most cases appear to be due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Classical treatment of SIADH with fluid restriction is frequently ineffective, and in some circumstances, such as following subarachnoid hemorrhage, contraindicated. However, the recently developed vasopressin receptor antagonist class of drugs provides a very useful tool in the management of neurosurgical SIADH. In this review, we summarize the existing literature on the clinical features, causes, and management of hyponatremia in the neurosurgical patient.

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.