Fluctuation of serum sodium and its impact on short and long-term mortality following acute pulmonary embolism

Effect of fosfomycin-induced hypernatremia on patients' hospital stay length and survival

BACKGROUND AND OBJECTIVE

Hypernatremia is a possible side effect of intravenous fosfomycin. The aim of this study was to investigate the effects of changes in sodium (Na) levels on hospital stay and survival in patients hospitalized in the intensive care unit receiving fosfomycin.

SUBJECTS AND METHODS

This study was conducted retrospectively on the files of patients over the age of 60, who were admitted to the Internal Medicine Intensive Care Unit. Plasma sodium levels were observed and documented over a period of 14 days. The patients were divided into two groups (Hypernatremia group Na > 145 mEq/L vs normonatremia group 135-145 mEq/L). In addition, daily sodium changes were noted for 14 days in patients.

RESULTS

The mean age of the patients was 75 years. Hospitalization days were longer for hypernatremia patients (31.5 days vs 41 days, p = 0.003). Patients with hypernatremia had an extended duration of stay in the intensive care unit. (21 days vs 31 days p = 0.002). The 1-month survival rate was 61.4% in patients with hypernatremia and 24.9% in patients without hypernatremia (p = 0.004). The absence of hypernatremia increases mortality by 2.09 times (95% CI 1.35-3.23). When discharge and mortality rates were analyzed according to sodium fluctuation, discharged patients exhibited a lower sodium fluctuation (4 min/max (-10/19) vs 6 min/max (-16/32) p < 0.001).

CONCLUSION

In conclusion, the strength of our study is that it specifically focuses on the consequences of the sodium fluctuation on patient management and provides results.

Hyponatremia-Long-Term Prognostic Factor for Nonfatal Pulmonary Embolism

Over recent years, studies have shown that in patients with left-sided heart failure, arterial hypertension, and acute coronary syndrome, hyponatremia is a negative prognostic factor. In this context, there is raising interest in the association between hyponatremia and pulmonary embolism (PE). This retrospective cohort study includes 404 consecutive patients with confirmed acute nonfatal pulmonary embolism divided into four groups according to their sodium fluctuation pattern. The primary outcome was all-cause mortality and determining the recurrence rate among patients with nonfatal PE using serum sodium levels as a continuous variable. Patients with acquired and persistent hyponatremia had a significantly higher rate of mortality rate than those in the normonatremia group (12.8% and 40.4%, OR- 7.206, CI: 2.383-21.791, p = 0.000 and OR-33.250, CI: 11.521-95.960, p = 0.000 vs. 2%, p < 0.001, respectively). Mean survival time decreases from 23.624 months (95% CI: (23.295-23.953)) in the normonatremia group to 16.426 months (95% CI: (13.17-19.134)) in the persistent hyponatremia group, statistically significant (p = 0.000). The mean survival time for all patients was 22.441 months (95% CI: (21.930-22.951)). The highest recurrence rate was recorded at 12 and 24 months in the acquired hyponatremia group (16.7% and 14.1%, respectively). Serum sodium determination is a simple and cost-effective approach in evaluating the short and long-term prognosis in patients with acute PE.

Trajectories of Serum Sodium on In-Hospital and 1-Year Survival among Hospitalized Patients

BACKGROUND AND OBJECTIVES

This study aimed to investigate the association between in-hospital trajectories of serum sodium and risk of in-hospital and 1-year mortality in patients in hospital.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a single-center cohort study. All adult patients who were hospitalized from years 2011 through 2013 who had available admission serum sodium and at least three serum sodium measurements during hospitalization were included. The trend of serum sodium during hospitalization was analyzed using group-based trajectory modeling; the five main trajectories were grouped as follows: (1) stable normonatremia, (2) uncorrected hyponatremia, (3) borderline high serum sodium, (4) corrected hyponatremia, and (5) fluctuating serum sodium. The outcome of interest was in-hospital mortality and 1-year mortality. Stable normonatremia was used as the reference group for outcome comparison.

RESULTS

A total of 43,539 patients were analyzed. Of these, 47% had stable normonatremia, 15% had uncorrected hyponatremia, 31% had borderline high serum sodium, 3% had corrected hyponatremia, and 5% had fluctuating serum sodium trajectory. In adjusted analysis, there was a higher in-hospital mortality among those with uncorrected hyponatremia (odds ratio [OR], 1.33; 95% CI, 1.06 to 1.67), borderline high serum sodium (OR, 1.66; 95% CI, 1.38 to 2.00), corrected hyponatremia (OR, 1.50; 95% CI, 1.02 to 2.20), and fluctuating serum sodium (OR, 4.61; 95% CI, 3.61 to 5.88), compared with those with the normonatremia trajectory. One-year mortality was higher among those with uncorrected hyponatremia (hazard ratio [HR], 1.28; 95% CI, 1.19 to 1.38), borderline high serum sodium (HR, 1.18; 95% CI, 1.11 to 1.26), corrected hyponatremia (HR, 1.24; 95% CI, 1.08 to 1.42), and fluctuating serum sodium (HR, 2.10; 95% CI, 1.89 to 2.33) compared with those with the normonatremia trajectory.

CONCLUSIONS

More than half of patients who had been hospitalized had an abnormal serum sodium trajectory during hospitalization. This study demonstrated that not only the absolute serum sodium levels but also their in-hospital trajectories were significantly associated with in-hospital and 1-year mortality. The highest in-hospital and 1-year mortality risk was associated with the fluctuating serum sodium trajectory.

PODCAST

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High mortality in patients presenting with acute pulmonary embolism and elevated INR not on anticoagulant therapy

The prognostic significance of patients presenting with pulmonary embolism (PE) and elevated International Normalised Ratio (INR) not on anticoagulant therapy has not been described. We investigated whether these patients had higher mortality compared to patients with normal INR. A retrospective study of patients admitted to a tertiary hospital with acute PE from 2000 to 2012 was undertaken, with study outcomes tracked using a state-wide death registry. Patients were excluded if they were taking anticoagulants or had inadequate documentation of their INR and medication status. Of the 1,039 patients identified, 94 (9 %) had an elevated INR (> 1.2) in the absence of anticoagulant use. These patients had higher mortality at six months follow-up (26 % vs 6 %, p< 0.001) compared to controls (INR ≤ 1.2). An INR > 1.2 at diagnosis was an independent predictor of death at six months post-PE (hazard ratio [HR] 2.9, 95 % confidence interval [CI] 1.8–4.7, p< 0.001). The addition of INR to a multivariable model that included the simplified pulmonary embolism severity index (sPESI), chest pain, and serum sodium led to a significant net reclassification improvement estimated at 8.1 %. The final model’s C statistic increased significantly by 0.04 (95 % CI 0.01–0.08, p=0.03) to 0.83 compared to sPESI alone (0.79). In summary, patients presenting with acute PE and elevated INR while not on anticoagulant therapy appear to be at high risk of death. Future validation studies in independent cohorts will clarify if this novel finding can be usefully incorporated into clinical decision making in patients with acute PE.

Predicting in-hospital death during acute presentation with pulmonary embolism to facilitate early discharge and outpatient management

Background

Pulmonary embolism continues to be a significant cause of death. The aim was to derive and validate a risk prediction model for in-hospital death after acute pulmonary embolism to identify low risk patients suitable for outpatient management.

Methods

A confirmed acute pulmonary embolism database of 1,426 consecutive patients admitted to a tertiary-center (2000–2012) was analyzed, with odd and even years as derivation and validation cohorts respectively. Risk stratification for in-hospital death was performed using multivariable logistic-regression modelling. Models were compared using receiver-operating characteristic-curve and decision curve analyses.

Results

In-hospital mortality was 3.6% in the derivation cohort (n = 693). Adding day-1 sodium and bicarbonate to simplified Pulmonary Embolism Severity Index (sPESI) significantly increased the C-statistic for predicting in-hospital death (0.71 to 0.86, P = 0.001). The validation cohort yielded similar results (n = 733, C-statistic 0.85). The new model was associated with a net reclassification improvement of 0.613, and an integrated discrimination improvement of 0.067. The new model also increased the C-statistic for predicting 30-day mortality compared to sPESI alone (0.74 to 0.83, P = 0.002). Decision curve analysis demonstrated superior clinical benefit with the use of the new model to guide admission for pulmonary embolism, resulting in 43 fewer admissions per 100 presentations based on a risk threshold for admission of 2%.

Conclusions

A risk model incorporating sodium, bicarbonate, and the sPESI provides accurate risk prediction of acute in-hospital mortality after pulmonary embolism. Our novel model identifies patients with pulmonary embolism who are at low risk and who may be suitable for outpatient management.

The Economic Burden of Hyponatremia: Systematic Review and Meta-Analysis

BACKGROUND

Hyponatremia is the most common electrolyte abnormality observed in clinical practice. Several studies have demonstrated that hyponatremia is associated with an increased length of hospital stay and of hospital resource utilization. To clarify the impact of hyponatremia on the length of hospitalization and costs, we performed a meta-analysis based on published studies that compared hospital length of stay and cost between patients with and without hyponatremia.

METHODS

An extensive Medline, Embase, and Cochrane search was performed to retrieve all studies published up to April 1, 2015 using the following words: "hyponatremia" or "hyponatraemia" AND "hospitalization" or "hospitalisation." A meta-analysis was performed including all studies comparing duration of hospitalization and hospital readmission rate in subjects with and without hyponatremia.

RESULTS

Of 444 retrieved articles, 46 studies satisfied the inclusion criteria, encompassing a total of 3,940,042 patients; among these, 757,763 (19.2%) were hyponatremic. Across all studies, hyponatremia was associated with a significantly longer duration of hospitalization (3.30 [2.90-3.71; 95% CIs] mean days; P < .000). Similar results were obtained when patients with associated morbidities were analyzed separately. Furthermore, hyponatremic patients had a higher risk of readmission after the first hospitalization (odds ratio 1.32 [1.18-1.48; 95% CIs]; P < .000). A meta-regression analysis showed that the hyponatremia-related length of hospital stay was higher in males (Slope = 0.09 [0.05-0.12; 95% CIs]; P = .000 and Intercept = -1.36 [-3.03-0.32; 95% CIs]; P = .11) and in elderly patients (Slope = 0.002 [0.001-0.003; 95% CIs]; P < .000 and Intercept = 0.89 [0.83-0.97; 95% CIs]; P < .001). A negative association between serum [Na(+)] cutoff and duration of hospitalization was detected. No association between duration of hospitalization, serum [Na(+)], and associated morbidities was observed. Finally, when only US studies (n = 8) were considered, hyponatremia was associated with up to around $3000 higher hospital costs/patient when compared with the cost of normonatremic subjects.

CONCLUSIONS

This meta-analysis confirms that hyponatremia is associated with a prolonged hospital length of stay and higher risk of readmission. These observations suggest that hyponatremia may represent one important determinant of the hospitalization costs.

Hyponatremia improvement is associated with a reduced risk of mortality: evidence from a meta-analysis

BACKGROUND

Hyponatremia is the most common electrolyte disorder and it is associated with increased morbidity and mortality. However, there is no clear demonstration that the improvement of serum sodium concentration ([Na(+)]) counteracts the increased risk of mortality associated with hyponatremia. Thus, we performed a meta-analysis that included the published studies that addressed the effect of hyponatremia improvement on mortality.

METHODS AND FINDINGS

A Medline, Embase and Cochrane search was performed to retrieve all English-language studies of human subjects published up to June 30th 2014, using the following words: "hyponatremia", "hyponatraemia", "mortality", "morbidity" and "sodium". Fifteen studies satisfied inclusion criteria encompassing a total of 13,816 patients. The identification of relevant abstracts, the selection of studies and the subsequent data extraction were performed independently by two of the authors, and conflicts resolved by a third investigator. Across all fifteen studies, any improvement of hyponatremia was associated with a reduced risk of overall mortality (OR=0.57[0.40-0.81]). The association was even stronger when only those studies (n=8) reporting a threshold for serum [Na(+)] improvement to >130 mmol/L were considered (OR=0.51[0.31-0.86]). The reduced mortality rate persisted at follow-up (OR=0.55[0.36-0.84] at 12 months). Meta-regression analyses showed that the reduced mortality associated with hyponatremia improvement was more evident in older subjects and in those with lower serum [Na(+)] at enrollment.

CONCLUSIONS

This meta-analysis documents for the first time that improvement in serum [Na(+)] in hyponatremic patients is associated with a reduction of overall mortality.

Hyponatraemia is an independent predictor of in-hospital mortality

BACKGROUND

Hyponatraemia increases morbidity and mortality, but the extent to which this condition influences mortality independently of other contributing factors is unclear.

MATERIALS AND METHODS

All hyponatremic patients admitted to the internal medicine department during a six month period were included. Medical records were reviewed and patients' demographics, underlying disease, cause of hyponatremia and in-hospital deaths were noted. Control group consisted of patients with normonatremia admitted to the same department during the same period matched 1:1 by sex, age and underlying disease. Difference in in-hospital mortality rate between the study and control groups was tested by chi-square test. Baseline demographics, underlying diseases, cause of hyponatremia and state of hyponatremia correction as possible risk factors for mortality were tested in a multivariate analysis.

RESULTS

The baseline cohort of all admitted patients consisted of 2,171 patients. Hyponatraemia was found in 278 (13%) patients (160 females and 118 males). The three most common causes of hyponatremia included gastrointestinal loss (52 patients), decreased oral intake (47 patients), and dilution hyponatremia (45 patients). The in-hospital mortality rate in the hyponatremic group was significantly higher compared with the control group (22% vs 7%, respectively; OR 3.75, 95% CI 2.17-6.48, p<0.0001). In a multivariate analysis age above 65 years, dilution hyponatremia, decreased oral intake as etiologic factors of hyponatremia, and unsuccessful hyponatremia correction were independent factors associated with increased mortality.

CONCLUSION

Hyponatraemia represents independent factor associated with in-hospital mortality. Age above 65 years, failure to correct hyponatremia and some specific etiologic factors of hyponatremia are related to increased mortality.