Sodium Fluctuations and Mortality in a General Hospitalized Population

Abstract

Background/Aims: Aim of our study was to describe the association between natremia (Na) fluctuation and hospital mortality in a general population admitted to a tertiary medical center. Methods: We performed a retrospective observational cohort study on the patient population admitted to the Fondazione Policlinico A. Gemelli IRCCS Hospital between January 2010 and December 2014 with inclusion of adult patients with at least 2 Na values available and with a normonatremic condition at hospital admission. Patients were categorized according to all Na values recorded during hospital stay in the following groups: normonatremia, hyponatremia, hypernatremia, and mixed dysnatremia. The difference between the highest or the lowest Na value reached during hospital stay and the Na value read at hospital admission was used to identify the maximum Na fluctuation. Cox proportional hazards models were used to estimate hazard ratios (HRs) for in-hospital death in the groups with dysnatremias and across quartiles of Na fluctuation. Covariates assessed were age, sex, highest and lowest Na level, Charlson/Deyo score, cardiovascular diseases, cerebrovascular diseases, dementia, congestive heart failure, severe kidney disease, estimated glomerular filtration rate, and number of Na measurements during hospital stay. Results: 46,634 admissions matched inclusion criteria. Incident dysnatremia was independently associated with in-hospital mortality (hyponatremia: HR 3.11, 95% CI 2.53, 3.84, p < 0.001; hypernatremia: HR 5.12, 95% CI 3.94, 6.65, p < 0.001; mixed-dysnatremia: HR 4.94, 95% CI 3.08, 7.92, p < 0.001). We found a higher risk of in-hospital death by linear increase of quartile of Na fluctuation (p trend <0.001) irrespective of severity of dysnatremia (HR 2.34, 95% CI 1.55, 3.54, p < 0.001, for the highest quartile of Na fluctuation compared with the lowest). Conclusions: Incident dysnatremia is associated with higher hospital mortality. Fluctuation of Na during hospital stay is a prognostic marker for hospital death independent of dysnatremia severity.

Serum sodium variability and acute kidney injury: a retrospective observational cohort study on a hospitalized population

“…Concerning this, it is interesting to note the median time between dysnatremia and the onset of AKI (7-8 days), as reported on Table 3. An interesting finding in our study, Na variability and kidney injury were associated independently from Na peak value (highest or lowest), in accordance with what has been shown by other Authors [8,27], suggesting a potentially more damaging role of Na rapid variations rather than Na absolute value. Evidence suggests that osmotic stress can cause cellular damage, even if we do not know the exact mechanism at kidney level.…”

“…Both hyponatremia and hypernatremia have been widely associated with increased morbidity and mortality. Furthermore, as suggested by recently published studies, even small fluctuations in serum Na levels have been associated with a significant increase of in-hospital mortality [5][6][7][8].…”

“…A growing body of recent evidences highlight the relationship between disorders of metabolism and electrolyte homeostasis and strong outcomes [8,27,28]. Several studies have described the association between Na balance and kidney function [11][12][13] however, a few of them have considered dysnatremia as predictor of AKI [14,19] and none has investigated Na variability as a marker in kidney injury development.…”

De-novo non-convulsive status epilepticus in adult medical inpatients without known epilepsy: Analysis of mortality related factors and literature review

“…Moreover, our series is, to our knowledge, the first to describe variables like hypernatremia and atrial fibrillation, which could help to identify high-risk patients when diagnosing NCSE. Hypernatremia is linked to a high mortality risk, not only in patients with NCSE, but in any older inpatient [42,43]. Atrial fibrillation is a risk factor linked to a higher mortality in older patients with any comorbidity, but its relevance in NCSE was not understood [44,45].…”

Dysnatremias in Chronic Kidney Disease: Pathophysiology, Manifestations, and Treatment

“…Table 1 shows the incidence and prevalence of hyponatremia in the studies of the general population, CKD not on dialysis, hemodialysis, and peritoneal dialysis ( 10 , 27 – 54 ). Table 2 shows the incidence and prevalence of hypernatremia in the same population segments ( 10 , 28 – 30 , 32 – 36 , 38 – 40 , 47 , 53 – 55 ). The values for prevalence and incidence related to dysnatremias vary widely in each of the four categories of patients in Tables 1 , 2 and overlap substantially among the four patient categories.…”