Evaluation of sodium intake for the prediction of cardiovascular events in Japanese high-risk patients: the ESPRIT Study

Association between sodium-to-potassium ratio in spot urine and hospitalization due to heart failure in high-risk Japanese patients

Background

In Japanese cardiovascular (CV) high-risk patients, the ESPRIT (Evaluation of Sodium Intake for the Prediction of Cardiovascular Events in Japanese High-risk Patients) study showed that high sodium excretion (≥4.0 g/day) was associated with a composite CV events of heart failure (HF) hospitalization, acute coronary syndrome, cerebrovascular events, and CV deaths. In this context, the sodium-to-creatinine (Na/Cr) ratio in spot urine was found to be significantly associated with HF hospitalizations. Since a stable potassium balance plays a particularly relevant role for CV patients, this post-hoc study was designed to investigate the extent to which consideration of the sodium-to-potassium (Na/K) ratio represents a better predictor of HF hospitalizations in the ESPRIT study population.

Methods

This is a post-hoc analysis of a previously reported ESPRIT study (n = 520, 60 HF hospitalizations).

Results

Receiver operating curve analysis yielded optimal Na/K ratio cut-off value of 2.9 for detecting HF hospitalization. Kaplan-Meier curve showed that high Na/K ratio in spot urine was associated with increased HF hospitalization (p < 0.001). Cox proportional hazards model analysis revealed that high Na/K ratio was associated with HF hospitalization with a hazard ratio of 2.97 (confidence interval: 1.67-5.61). An association between high Na/K ratio and HF hospitalization remained after adjustments for Na/Cr ratio in spot urine or the use of diuretics.

Conclusion

The Na/K ratio in spot urine is associated with HF hospitalization in high-risk Japanese patients.

Sodium status is associated with type 2 diabetes mellitus: a systematic review and meta-analysis of observational studies

PURPOSE

The relationship between sodium intake and the risk of developing type 2 diabetes mellitus (T2DM) is inconsistent. We, therefore, aimed to summarize the current evidence by conducting a systematic review and meta-analysis of observational studies.

METHODS

We retrieved studies which compared any marker of sodium status between individuals with T2DM and those without diabetes published in any language by searching online databases from inception up to June 2019. Summary effects were derived using random-effects model.

RESULTS

A total of 44 studies with 503,830 participants from 25 countries were included in this study. Sodium status was significantly different between individuals with and without T2DM (Hedges' g = 0.21; 95% CI 0.02, 0.40; P = 0.029). Individuals with T2DM had higher sodium intake compared to non-diabetic controls (WMD = 621.79 mg/day; 95% CI 321.53, 922.06; P < 0.001) and 24-h urinary excretion was associated with likelihood of developing T2DM (OR = 1.27, 95% CI 1.15, 1.41; P < 0.001). Furthermore, salivary, hair, and platelet sodium were higher in patients with T2DM compared to controls (P < 0.05).

CONCLUSION

The findings of the current meta-analysis suggest that sodium levels are higher in patients with T2DM compared to non-diabetic controls; however, given that these studies are observational, it is not possible to infer causality.

Nitric Oxide Alleviated High Salt-Induced Cardiomyocyte Apoptosis and Autophagy Independent of Blood Pressure in Rats

The present study aimed to explore whether high-salt diet (HSD) could cause cardiac damage independent of blood pressure, and whether nitric oxide (NO) could alleviate high-salt–induced cardiomyocyte apoptosis and autophagy in rats. The rats received 8% HSD in vivo. H9C2 cells or primary neonatal rat cardiomyocytes (NRCM) were treated with sodium chloride (NaCl) in vitro. The levels of cleaved-caspase 3/caspase 3, cleaved-caspase 8/caspase 8, Bax/Bcl2, LC3 II/LC3 I, Beclin-1 and autophagy related 7 (ATG7) were increased in the heart of HSD rats with hypertension (HTN), and in hypertension-prone (HP) and hypertension-resistant (HR) rats. Middle and high doses (50 and 100 mM) of NaCl increased the level of cleaved-caspase 3/caspase 3, cleaved-caspase 8/caspase 8, Bax/Bcl2, LC3 II/LC3 I, Beclin-1, and ATG7 in H9C2 cells and NRCM. The endothelial NO synthase (eNOS) level was increased, but p-eNOS level was reduced in the heart of HSD rats and H9C2 cells treated with 100 mM NaCl. The level of NO was reduced in the serum and heart of HSD rats. NO donor sodium nitroprusside (SNP) reversed the increases of cleaved-caspase 3/caspase 3, cleaved-caspase 8/caspase 8, Bax/Bcl2 induced by NaCl (100 mM) in H9C2 cells and NRCM. SNP treatment attenuated the increases of cleaved-caspase 3/caspase 3, Bax/Bcl2, LC3 II/LC3 I, Beclin-1, and ATG7 in the heart, but had no effect on the blood pressure of HSD rats with HR. These results demonstrated that HSD enhanced cardiac damage independently of blood pressure. Exogenous NO supplementarity could alleviate the high salt–induced apoptosis and autophagy in cardiomyocytes.

Dietary Sodium Intake and Health Indicators: A Systematic Review of Published Literature between January 2015 and December 2019

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.

Factors associated with heart failure hospitalization in patients with high sodium excretion: subanalysis of the ESPRIT, evaluation of sodium intake for the prediction of cardiovascular events in Japanese high-risk patients, cohort study

We have reported that high sodium excretion ≥ 4.0 g/day, assessed by repeated measurements of spot urine, is associated with composite cardiovascular (CV) events of heart failure (HF) hospitalization, acute coronary syndrome, cerebrovascular events, and documented CV deaths in Japanese high-risk patients with either stable and compensated congestive HF, high brain natriuretic peptide, coronary artery disease, cerebrovascular disease, chronic kidney disease, or atrial fibrillation. A total of 520 patients were enrolled. During the median follow-up period of 5.2 years, 105 (20%) experienced composite CV events, which were predominantly driven by 60 (12%) HF hospitalizations. The aim of the present study was to elucidate which subgroups of patients with high sodium excretion were associated with HF hospitalization. We divided the enrolled patients into three groups according to the amount of sodium excretion (< 3.0 g/day, 3.0-3.99 g/day (reference), and ≥ 4.0 g/day) based on a median of 14 measurements during follow-up. We assessed the hazard ratio for HF hospitalization according to age, bodyweight, and gender, using the Cox hazard model. In the total population, high sodium excretion ≥ 4.0 g/day was associated with HF hospitalization [hazard ratio (HR) 1.75, confidence interval (CI) 1.05-2.83] after adjustment for gender, age, and bodyweight, but was not associated with other CV events. In older patients (≥ 75 years old), high sodium excretion ≥ 4.0 g/day was associated with HF hospitalization after adjustment for gender and bodyweight (HR 3.25, CI 1.55-6.55), which was not observed in younger (< 75 years old) patients. In patients with lower bodyweight (< 60 kg), high sodium excretion ≥ 4.0 g/day was associated with HF hospitalization after adjustment for age and gender (HR 3.05, CI 1.34-6.61), which was not observed in heavier (≥ 60 kg) patients. High sodium excretion is associated with HF hospitalization in patients with older age and lower bodyweight in Japanese high-risk patients.