Outcomes in medical admissions with hyponatraemia in Ghana – a single-centre study

Abstract

Introduction: Hyponatraemia is the most common electrolyte abnormality in hospitalized patients and is associated with poor prognosis and high mortality. There is a paucity of data on hyponatraemia in Ghana. We set out to describe the prevalence of this condition, its associations and the outcomes in terms of in-hospital mortality and length of hospital stay. Methods: We conducted a retrospective study of all admissions from October 2017 to April 2018 on the medical ward at the Komfo Anokye Teaching Hospital (KATH). Demographic information, medical diagnoses as well as clinical and laboratory data were documented. Means (± standard deviation) were recorded for normally distributed data, whereas non-normally distributed data were recorded as medians [interquartile range (IQR)]. Chi-squared and Fisher's exact tests were used to test categorical variables. ANOVA and Kruskal-Wallis tests were used for the analysis of hyponatraemia severity; a p value of < 0.05 was considered statistically significant. Results: Within the study period, 406 patients with hyponatraemia were identified in 1477 medical admissions, a prevalence of 27.6%. Their mean age was 51.5 ± 19.0 years. There were 217 males (53.5%). The mean serum sodium was 128.7 ± 6.5 mmol/L. Two hundred and forty (59%) had mild hyponatraemia, 106 (26%) had moderate hyponatraemia and 60 (15%) had severe hyponatraemia. The most common associated medical conditions were infections (26%), chronic liver disease (17%), hyperglycaemia (17%), chronic kidney disease (16%) and chronic heart failure (8%). In-hospital mortality was 31.8% and varied with the severity of the hyponatremia. The median length of hospital stay was 7 days (IQR 4-10 days) and did not vary with the severity of hyponatraemia. Mortality was associated with serum sodium concentration (p = 0.007) and lower levels of consciousness (Glasgow Coma Scale, GCS, ≤ 13) at presentation (p < 0.001). Conclusions: Hyponatraemia is common in medical admissions in Ghana, and is mostly associated with infections, and chronic liver, kidney and heart diseases. It is associated with high in-hospital mortality, especially when hyponatraemia is more severe or accompanied by relatively low GCS scores.

Hyponatraemia as a predictor of mortality in medical admissions in Ghana - A case control study

“…to December 2018 as a follow up to an earlier study of patients with only hyponatraemia conducted from October 2017 to April 2018 [3]. We identi ed medical patients on admission with normonatraemia and recorded their medical diagnoses, demographics and laboratory data.…”

“…It is de ned as serum sodium concentration of less than 135 mmol/L [2]. Hyponatraemia occurs in 27.6% of hospitalized medical patients in Ghana [3] and associated with high mortality [4]. Hyponatraemia indicates a disruption in the body's water balance due to abnormal handling of water by the kidneys from antidiuretic hormone (ADH) secretion (appropriately or inappropriately) or an excessive water intake [2,5].…”

“…Nonosmotic states such as pain, anxiety and nausea are also reported as causes of hyponatremia in acute cases [7]. Infections have been shown to be the most common cause of hyponatraemia among medical admissions in Ghana [3].…”

“…The in-hospital mortality in medical patients was found to be 31.8% in a recent hospital based study in Ghana [3]. It is however not certain whether hyponatraemia is direct cause of mortality, a poor prognostic indicator for chronic medical conditions such as malignancies, chronic kidney disease, chronic liver disease, brain tumour and intracerebral hemorrhage [4] or just an 'innocent bystander' as the underlying condition causes mortality [10].…”

“…In Ghana, there has been a single centre study to describe the demographics, causes and outcomes of patients with hyponatraemia [3] but there has not been any study to compare the mortality of patients with hyponatraemia and those with normal sodium concentration in hospitalized patients to ascertain if there is a difference in mortality and length of hospital stay. With our knowledge of the mortality in patients with hyponatraemia, we set out to compare the outcomes of patients with documented hyponatraemia to those with normonatraemia in terms of in-hospital mortality and length of hospital stay and to determine the predictors of in-hospital mortality among medical admissions in tertiary institution in Ghana.…”