Serum sodium improvement: change in Comprehensive Geriatric Assessment parameters in geriatric patients with hyponatremia.

BACKGROUND: Hyponatremia presents with symptoms considered age-associated in the elderly. We assess the change in Comprehensive Geriatric Assessment (CGA) parameters after hyponatremia improvement in hospitalized geriatric patients. METHODS: We took 100 hyponatremic and same number of eunatremic geriatric patients (> 60 years) who were comorbidity, presenting-complaints, and age-matched. Four CGA parameters were utilized, the new Hindi Mental State Examination (HMSE), Barthel's index of activities of daily living (ADL), Timed up and go Test (TUG), and handgrip strength by hand dynamometer (HG). We analyzed these at admission and discharge, and their relationship with change in sodium levels. RESULTS: Average age was 68.1 ± 5.8 years, with males constituting 75%. The CGA parameters demonstrated worse values amongst the hyponatremia than the normonatremia group. Severe hyponatremia group showed worse CGA scores in comparison with moderate and mild. With improvement in sodium level, the improvements in ADL, TUG, and HMSE scores were greater in the hyponatremia group (8.8 ± 10.1, 2.2 ± 2.5, and 1.7 ± 2.3 respectively) in comparison to the normonatremia reference group (4.7 ± 9.0, 1 ± 2.0, and 0.7 ± 1.3 respectively, P < 0.05). CONCLUSION: Our study is the first utilizing HMSE to assess change in cognitive ability with improvement in serum sodium levels in the Indian elderly. Hyponatremic patients show worse baseline CGA parameters, and hyponatremia severity correlates with worse motor and cognitive function. Improvement in the serum sodium level improves the CGA parameters. Correction of hyponatremia in the geriatric age group significantly impacts life quality.

Chloride and Potassium Assessment Is a Helpful Tool for Differential Diagnosis of Thiazide-Associated Hyponatremia.

CONTEXT: Differential diagnosis of thiazide-associated hyponatremia (TAH) is challenging. Patients can either have volume depletion or a syndrome of inappropriate antidiuresis (SIAD)-like presentation. OBJECTIVE: To evaluate the impact of the simplified apparent strong ion difference in serum (aSID; sodium + potassium - chloride) as well as the urine chloride and potassium score (ChU; chloride - potassium in urine) in the differential diagnosis of TAH, in addition to assessment of fractional uric acid excretion (FUA). METHODS: Post hoc analysis of prospectively collected data from June 2011 to August 2013 from 98 hospitalized patients with TAH < 125 mmol/L enrolled at University Hospital Basel and University Medical Clinic Aarau, Switzerland. Patients were categorized according to treatment response in volume-depleted TAH requiring volume substitution or SIAD-like TAH requiring fluid restriction. We computed sensitivity analyses with ROC curves for positive predictive value (PPV) and negative predictive value (NPV) of aSID, ChU, and FUA in differential diagnosis of TAH. RESULTS: An aSID > 42 mmol/L had a PPV of 79.1% in identifying patients with volume-depleted TAH, whereas a value < 39 mmol/L excluded it with a NPV of 76.5%. In patients for whom aSID was inconclusive, a ChU < 15 mmol/L had a PPV of 100% and a NPV of 83.3%, whereas FUA < 12% had a PPV of 85.7% and a NPV of 64.3% in identifying patients with volume-depleted TAH. CONCLUSION: In patients with TAH, assessment of aSID, potassium, and chloride in urine can help identifying patients with volume-depleted TAH requiring fluid substitution vs patients with SIAD-like TAH requiring fluid restriction.

Sodium assessment in neonates, infants, and children: a systematic review.

Hyponatremia is a common disorder in childhood. The indirect and the direct potentiometry are currently the most popular techniques employed for sodium assessment, although discrepancies between the two techniques may be > 10 mmol/L. It is known that < 20% of the recently published articles report information about the technique used for sodium analysis, but no data are available on pediatric studies. This study aimed at investigating the laboratory technique employed for sodium measurement in studies conducted in childhood. A systematic literature search in PubMed, Embase, and Web of Science was undertaken to identify articles containing the word "hyponatremia" in the title between 2013 and 2020. Papers with < 10 subjects were excluded. A total of 565 articles were included. Information on the laboratory technique used for sodium analysis was more commonly (p = 0.035) reported in pediatric (n = 15, 28%) than in non-pediatric (n = 81, 16%) reports. The frequency of reports with and without information on the technique for sodium assessment was not different with respect to the study characteristics, the quartile of the journal where the paper was published, the country income setting, and the inclusion of neonates among the 54 pediatric studies.   Conclusion: Most pediatric papers do not report any information on the technique used for sodium analysis. Although international authorities have recommended the implementation of direct potentiometry, a low awareness on this issue is still widespread in pediatric research. What is Known: • Direct potentiometry and indirect potentiometry are currently employed for sodium analysis in blood. • Direct potentiometry is more accurate. What is New: • Less than 30% of pediatric articles provide information on the technique employed for sodium analysis in blood. • Indirect potentiometry is more frequently employed than direct potentiometry in pediatric studies.

Serum Sodium Improvement: Effect on Comprehensive Geriatric Assessment Parameters in Hyponatremic Geriatric Patients in a Tertiary Care Center.

Hyponatremia prevalence is 22.2% in the geriatric age group as compared to 6% for other patients. Symptomatology of hyponatremia is subtle and is often interpreted as age-related in the geriatric patients. We use various Comprehensive Geriatric Assessment (CGA) parameters to analyze the impact of improvement in serum sodium levels. MATERIAL: We utilized four simple CGA parameters, the new Hindi Mental State Examination (HMSE) for assessing the cognition, Barthel index of activities of daily living (ADL) for the level of independence, Timed up and go test (TUG test) for risk of fall evaluation, and handgrip strength (HG) by hand dynamometer for frailty. All parameters were analyzed at admission and at discharge, and their relation with the severity of hyponatremia in 100 geriatric patients (>60 years) was seen. Equal number of hyponatremic geriatric patients were taken, matched for comorbidity, reason for presentation, and age. OBSERVATION: Mean age of the study population was 68.1 ± 5.8 years, with a male: female ratio of 3:1. Baseline sodium level in hyponatremia and normonatremia groups were 129.7 ± 5.1 and 139 ± 3.4 meq/L (P=2.4) respectively. All CGA parameters tested showed lower values among hyponatremic patients compared to normonatremic patients, although only ADL (71.6 ± 12.3 v/s 76.7 ± 11.5, P=0.001) and HMSE (23.4 ± 3.1 v/s 24.4 ± 2.4, P=0.01) were statistically significant. All parameters were worse in the severe hyponatremia group (Na<125 meq/L) compared to moderate (Na=125-130 meq/L) and mild (Na=130-135 meq/L), but significant only for TUG (17.9 ± 3.4 v/s 16.4 ± 4.2 v/s 14.6 ± 3.5, P=0.003, higher value being worse) and HMSE (21.1 ± 4.0 v/s 22.6 ± 2.8 v/s 24.1 ± 2.5, P=0.0007). Improvement in ADL, TUG, and HMSE scores with serum sodium improvement was significantly higher in the hyponatremia group (8.8 ± 10.1, 2.2 ± 2.5, and 1.7 ± 2.3 respectively) when compared to the normonatremic reference group (4.7 ± 9.0, 1 ± 2.0, and 0.7 ± 1.3 respectively, P<0.05). Although HG improvement was also greater, the difference was not statistically significant. CONCLUSION: Ours is the first study utilizing HMSE for assessing the cognition in the Indian patients. Hyponatremic patients have poor baseline CGA parameter values, and severity of hyponatremia correlates with poor motor and cognitive functions. Improvement in serum sodium levels improve CGA parameters. Hyponatremia correction should be prioritized in the elderly as it significantly impacts the quality of life in the elderly.

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.

ICU Emergencies Simulation Curriculum for Critical Care Fellows: Neurologic Emergencies.

Introduction: The management of neurologic emergencies is an important component of critical care fellowship training. Additional training in neurocritical care has been demonstrated to improve clinical outcomes, though exposure to these emergencies during training can be limited. Methods: Three simulation cases are presented as part of a comprehensive neurologic emergencies curriculum for critical care trainees. The cases represent neurologic catastrophes encountered in the intensive care unit consisting of symptomatic hyponatremia, severe alcohol withdrawal syndrome, and brain herniation syndrome. The case descriptions are complete with learning objectives, critical actions checklists, and debriefing material for facilitators, as well as all necessary personnel briefs and required equipment. Results: The scenarios were completed over the course of the 2016-2017 academic year by first-year critical care fellows. Following curriculum implementation, there was an improvement in self-perceived confidence of fellows in neurologic emergency management skills. Discussion: The cases were felt to be realistic and beneficial and led to perceived improvement in management of neurologic emergencies and leadership during clinical crises.

Management of hyponatremia: causes, clinical aspects, differential diagnosis and treatment.

INTRODUCTION: Hyponatremia is the most frequent electrolyte disorder in hospitalised patients. Acute and severe hyponatremia may be a life-threatening situation. However, also mild and chronic hyponatremia may negatively affect the health status (i.e. gait disturbances, attention deficits, falls and fractures, and bone loss) and may increase the risk of death. Therefore, it is of paramount importance for clinicians to have an in-depth knowledge on this topic, in order to appropriately manage patients affected by hyponatremia. AREAS COVERED: This review will cover different areas related to this electrolyte disorder. Because many pathologic conditions may be associated with hyponatremia, thorough investigations have to be performed in order to establish the underlying etiology. To establish the cause of hyponatremia is of great importance, because an appropriate therapeutic strategy is strictly dependent on a correct diagnosis. A description of the different available therapeutic approaches for the correction of hyponatremia, including vaptans, will follow. EXPERT COMMENTARY: Undoubtedly, the studies that have been published in recent years and the introduction of vaptans in clinical practice have contributed to increase the awareness on hyponatremia among clinicians. Nevertheless, additional studies are needed in order to clarify some partially uncovered areas.

Quality and cost considerations in hyponatraemic patients needing hospitalisation.

BACKGROUND: Hyponatraemia is the most common electrolyte disorder encountered in hospitalised patients and has an impact on outcome and survival. However, the risk factors are not yet sufficiently known. AIMS OF THE STUDY: This retrospective analysis was conducted with the primary objective to identify the incidence of hyponatraemia in patients, who need hospitalisation from any medical reason, focusing on the quality of treatment and the risk factors for recurrent or prolonged stay due to hyponatraemia. The secondary objectives were the calculation of costs of hyponatraemia caused by hospital stays in the canton of Basel-Landschaft and the additional extrapolation of these costs for the whole country of Switzerland. METHODS: 368 patients with a diagnosis of hyponatraemia admitted to three tertiary care centers in 2011 were included. We analysed the risk factors, causes and manifestations of hyponatraemia and their effects on length of stay and outcome. RESULTS: Female gender (62%), advanced age (average 75 ± 12 years) and the use of thiazides (r = 0.69, p = 0.03) represented the main risk factors with negative prognostic value concerning hyponatraemia. Hyponatraemia was never asymptomatic. Seventy-three patients (20%) were diagnosed with hyponatraemia due to SIADH (syndrome of inappropriate antidiuretic hormone secretion). The in-hospital mortality rate was 9%, irrespective of the severity of hyponatraemia, and every fifth patient had persistent neurological deficits on discharge from the hospital. Age (r = 0.65, p = 0.03), female sex (r = 0.49, p =0.12; in combination with age >75years r = 0.58, p = 0.049), resumption of risk medication (r = 0.563, p = 0.02) and persistent hyponatraemia on discharge (r = -0.51, p = 0.04) were associated with higher probability of relapse. Our data, extrapolated for Switzerland, yield uncovered annual costs of 93 million CHF, mostly due to in-hospital treatment longer than that reimbursed by SwissDRG (observed median of 9 days, cost coverage by SwissDRG 5 days for non-SIADH hyponatraemia and 6.5 days for SIADH). CONCLUSIONS: As even mild hyponatraemia is associated with an increased risk of morbidity and mortality, it is highly important to recognise it. Initial diagnostic evaluation, treatment based on volume status and thorough follow-up are crucial to avoid relapse. Hyponatraemia, based on the results of this retrospective study, constitutes a considerable medical and economic burden in Switzerland and has a serious impact on the hospital balance sheets.

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.

CT-pro-AVP as a tool for assessment of intravascular volume depletion in severe hyponatremia.

BACKGROUND: Assessment of volume status is essential to best manage hyponatremic patients but is not always accurate in clinical practice. The aim of this study was to evaluate the reliability of C-terminal portion of pro-arginine-vasopressin (CT-pro-AVP), a surrogate biomarker of vasopressin release, in assessing intravascular volume (IVV) depletion in hypoosmolar hyponatremic patients. METHODS: Plasma CT-pro-AVP and urea-to-creatinine ratio (Ur/Cr) were performed in 131 hospitalized patients presenting chronic severe hypoosmolar hyponatremia. At hospital discharge, their IVV was evaluated regardless of CT-pro-AVP concentrations. All patients were then classified as decreased or as normal/expanded IVV group. RESULTS: Plasma CT-pro-AVP levels were higher in patients with decreased IVV (34.6 vs. 11.3 pmol/L, p<0.001) and exhibited a reliable performance for assessment of decreased IVV (ROC AUC at 0.717 [95% CI 0.629-0.805]). The combination of CT-pro-AVP and Ur/Cr resulted in an improved ROC AUC up to 0.787 (95% CI 0.709-0.866). CONCLUSIONS: Our findings support the hypothesis that CT-pro-AVP plasma level may reflect IVV and would be a tool for its assessment. This performance has been magnified by its combination with Ur/Cr. A dual-marker strategy may help clinicians to optimize the management of severe hyponatremia especially in case of confusing clinical presentations.

Mid-regional pro-atrial natriuretic peptide and the assessment of volaemic status and differential diagnosis of profound hyponatraemia.

BACKGROUND: Hyponatraemia is common and its differential diagnosis and consequent therapy management is challenging. The differential diagnosis is mainly based on the routine clinical assessment of volume status, which is often misleading. Mid-regional pro-atrial natriuretic peptide (MR-proANP) is associated with extracellular and cardiac fluid volume. METHODS: A total of 227 consecutive patients admitted to the emergency department with profound hypo-osmolar hyponatraemia (Na < 125 mmol L(-1) ) were included in this prospective multicentre observational study conducted in two tertiary centres in Switzerland. A standardized diagnostic evaluation of the underlying cause of hyponatraemia was performed, and an expert panel carefully evaluated volaemic status using clinical criteria. MR-proANP levels were compared between patients with hyponatraemia of different aetiologies and for assessment of volume status. RESULTS: MR-proANP levels were higher in patients with hypervolaemic hyponatraemia compared to patients with hypovolaemic or euvolaemic hyponatraemia (P = 0.0002). The area under the curve (AUC) to predict an excess of extracellular fluid volume, compared to euvolaemia, was 0.73 [95% confidence interval (CI) 0.62-0.84]. Additionally, in multivariate analysis, MR-proANP remained an independent predictor of excess extracellular fluid volume after adjustment for congestive heart failure (P = 0.012). MR-proANP predicted the syndrome of inappropriate antidiuresis (SIAD) versus hypovolaemic and hypervolaemic hyponatraemia with an AUC of 0.77 (95% CI 0.69-0.84). CONCLUSION: MR-proANP is associated with extracellular fluid volume in patients with hyponatraemia and remains an independent predictor of hypervolaemia after adjustment for congestive heart failure. MR-proANP may be a marker for discrimination between the SIAD and hypovolaemic or hypervolaemic hyponatraemia.

Low prevalence of hyponatremia codification in departments of internal medicine and its prognostic implications.

OBJECTIVE: Hyponatremia is the most frequent ionic disorder among ambulatory and hospitalized populations. The aim of the study is to describe the profile of patients admitted to internal medicine departments of Spanish hospitals with a diagnostic codification of hyponatremia in their discharge sheets. METHODS: Data from the Minimum Basic Data Set (MBDS) of discharged patients from all departments of internal medicine (IM) of the Spanish National Health System (NHS) between 2007 and 2010 were analyzed to describe the profile of patients with diagnostic codification of hyponatremia. RESULTS: A total of 2,134,363 admittances were analyzed, identifying 31,933 (1.5%) with a diagnostic code of hyponatremia (18.3% as principal diagnosis and 81.7% as secondary diagnosis). Mortality among patients with codified hyponatremia was markedly higher than in patients without this condition (13.1% vs 9.8% [OR 1.38; 95% CI 1.33-1.41]). Hyponatremia codification was independently associated with a higher risk of readmission (OR 1.33 CI 95% 1.29-1.38). Average length of stay for patients with hyponatremia was 11.67 days (SD 13.01), compared to 9.84 days (SD 11.61) among the general population admitted to IM (p < 0.001). Mean cost per admission in the presence of codified hyponatremia was €4023 (SD €2531), compared to €3537 (SD €2858.02); p < 0.001. Hyponatremia was more prevalent among patients with the following conditions: dementia, chronic and acute renal failure, hepatic cirrhosis, pressure ulcers, heart failure, and depression. CONCLUSIONS: We found an extremely low prevalence of hyponatremia codification in our series (1.5%). Hyponatremia is underreported and undertreated although numerous studies have shown its devastating impact on hospital admittance. The first step in order to improve this situation is to raise awareness among physicians about a problem that despite its high prevalence is still overlooked.

Clinical judgment is the most important element in overhydration assessment of chronic hemodialysis patients.

BACKGROUND: The assessment of hydration status remains a challenging task in hemodialysis (HD) management. There are only limited data available on the relevance of clinical decisions in the estimation of dialysis overhydration (OH). The objective of this study was to examine the significance of clinical judgment in the assessment of pre-dialysis OH. METHODS: We compared the performance of three methods of OH assessment: (1) clinical judgment guided by a single clinical examination with (2) multifrequency bioimpedance analysis (BIA) and (3) complex systematic clinical approach. We additionally studied the associations of these methods with selected laboratory and imaging parameters. RESULTS: Any of the single parameters alone reached a sufficient level of accuracy for reliable prediction of OH. Clinical judgment was the single most important factor in OH estimation, and also had the highest contribution when in combination with other parameters. BIA reliably measured extracellular fluid, but the automatically calculated OHBIA exhibited a substantial degree of inaccuracy that precludes the use of BIA as a standard at present. The combination of clinical judgment with additional clinical parameters had the highest prediction accuracy for OH. Among the parameters studied, vena cava collapsibility index and calf circumference showed the strongest association with OH. Echocardiography, cardiothoracic index, atrial natriuretic peptide levels and spirometry did not have acceptable sensitivity. CONCLUSION: The systematic clinical approach combining physician and patient inputs, laboratory and imaging data enables an individualized decision and a superior accuracy in OH assessment.

Where vaptans do and do not fit in the treatment of hyponatremia.

The treatment of hyponatremia, an exceedingly common electrolyte disorder, has been a subject of controversy for many years. The advent of vasopressin antagonists (vaptans) has added to the treatment arsenal. This review focuses on why hyponatremia should be treated and the role of these antagonists in the treatment. Upon analysis of the available literature, we conclude that there is presently no role for vaptans in acute symptomatic hyponatremia. Although numerous therapeutic approaches are available for chronic symptomatic hyponatremia, vasopressin antagonists provide a simpler treatment option. Vaptans are efficacious in raising serum sodium in long-standing 'asymptomatic' hyponatremia. However, the cost of the only Food and Drug Administration-approved oral agent (tolvaptan) makes its use prohibitive for most patients in this setting.

Perspectives on the management of hyponatraemia secondary to SIADH across Europe.

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is the most common cause of euvolaemic hyponatraemia. However, although first described over 50 years ago, the management of hyponatraemia secondary to SIADH is not always straightforward. Some of the issues surrounding the management of hyponatraemia secondary to SIADH were explored in the European Hyponatraemia Survey completed by attendees of the European Hyponatraemia Network Academy Meeting 2011. This article describes the findings of this survey and the specific issues raised regarding the management of hyponatraemia secondary to SIADH in Europe. Some of these issues - including awareness, education, diagnosis, management and cost considerations of the condition - were common to countries across Europe.

Region 11 MELD Na exception prospective study.

INTRODUCTION: Hyponatremia complicates cirrhosis and predicts short term mortality, including adverse outcomes before and after liver transplantation. MATERIAL AND METHODS: From April 1, 2008, through April 2, 2010, all adult candidates for primary liver transplantation with cirrhosis, listed in Region 11 with hyponatremia, were eligible for sodium (Na) exception. RESULTS: Patients with serum sodium (SNa) less than 130 mg/dL, measured two weeks apart and within 30 days of Model for End Stage Liver Disease (MELD) exception request, were given preapproved Na exception. MELD Na was calculated [MELD + 1.59 (135-SNa/30 days)]. MELD Na was capped at 22, and subject to standard adult recertification schedule. On data end of follow-up, December 28, 2010, 15,285 potential U.S. liver recipients met the inclusion criteria of true MELD between 6 and 22. In Region 11, 1,198 of total eligible liver recipients were listed. Sixty-two (5.2%) patients were eligible for Na exception (MELD Na); 823 patients (68.7%) were listed with standard MELD (SMELD); and 313 patients (26.1%) received HCC MELD exception. Ninety percent of MELD Na patients and 97% of HCC MELD patients were transplanted at end of follow up, compared to 49% of Region 11 standard MELD and 40% of U.S.A. standard MELD (USA MELD) patients (p < 0.001); with comparable dropout rates (6.5, 1.6, 6.9, 9% respectively; p = 0.2). MELD Na, HCC MELD, Region 11 SMELD, and USA MELD post-transplant six-month actual patient survivals were similar (92.9, 92.8, 92.2, and 93.9 %, respectively). CONCLUSION: The Region 11 MELD Na exception prospective trial improved hyponatremic cirrhotic patient access to transplant equitably, and without compromising transplant efficacy.

Suppression of information on the prevalence and prevention of exercise-associated hyponatraemia.

It has been suggested recently that financial links between manufacturers of sports drinks and professional Sports Science organisations in North America have suppressed information on the existence and ways of preventing an epidemic of exercise-associated hyponatraemia (EAH). This article reviews evidence for the prevalence of both biochemical and clinical hyponatraemia. It concludes that a limited number of cases of EAH occur after ultra-long distance events, particularly when performed under cold and wet conditions, and that some eight deaths have been associated with EAH since 1985. However, this information has been widely reported, both in North America and in other parts of the world. Claims of an 'epidemic' seem unwarranted, and there is no solid evidence supporting the claim that information has been suppressed because of ties between sports scientists and sports drink manufacturers.