High Urinary Sodium Excretion Research Articles

Urinary sodium excretion and kidney disease progression in IgA nephropathy: A cohort study.

The role of dietary sodium intake in the risk of CKD progression remains controversial. This study aimed to evaluate the association of urinary sodium excretion and progression of IgA nephropathy. We assessed 596 patients with IgA nephropathy, urinary sodium excretion was measured at the time of kidney biopsy. Cox proportional hazards models and restricted cubic splines were used to assess the association between urinary sodium excretion and kidney disease progression events, defined as 50% eGFR decline or development of kidney failure. After a mean follow-up of 58.9 months, a total of 75 (12.6%) participants of IgA nephropathy reached composite kidney disease progression events. The risk of kidney disease progression events was higher in patients with higher urinary sodium excretion. After adjustment for traditional risk factors, higher levels of ln transformed urinary sodium excretion was associated with the kidney disease progression events in patients with IgA nephropathy (HR, 2.1; 95% CI, 1.4-3.2). In reference to the first tertile of urinary sodium excretion, hazard ratios were 1.9 (95% CI, 1.0-3.4) for the second tertile, 2.1 (95% CI, 1.1-3.9) for the third tertile. Higher levels of urinary sodium excretion were associated with kidney disease progression events in IgA nephropathy independent of clinical and biopsy characteristics.

Blood pressure variability in acute stroke: Risk factors and association with functional outcomes at 1 month.

Blood pressure variability, in acute stroke, may be an important modifiable determinant of functional outcome after stroke. In a large international cohort of participants with acute stroke, it was sought to determine the association of blood pressure variability (in the early period of admission) and functional outcomes, and to explore risk factors for increased blood pressure variability. INTERSTROKE is an international case-control study of risk factors for first acute stroke. Blood pressure was recorded at the time of admission, the morning after admission and the time of interview in cases (median time from admission 36.7 h). Multivariable ordinal regression analysis was employed to determine the association of blood pressure variability (standard deviation [SD] and coefficient of variance) with modified Rankin score at 1-month follow-up, and logistic regression was used to identify risk factors for blood pressure variability. Amongst 13,206 participants, the mean age was 62.19 ± 13.58 years. When measured by SD, both systolic blood pressure variability (odds ratio 1.13; 95% confidence interval 1.03-1.24 for SD ≥20 mmHg) and diastolic blood pressure variability (odds ratio 1.15; 95% confidence interval 1.04-1.26 for SD ≥10 mmHg) were associated with a significant increase in the odds of poor functional outcome. The highest coefficient of variance category was not associated with a significant increase in risk of higher modified Rankin score at 1 month. Increasing age, female sex, high body mass index, history of hypertension, alcohol use, and high urinary potassium and low urinary sodium excretion were associated with increased blood pressure variability. Increased blood pressure variability in acute stroke, measured by SD, is associated with an increased risk of poor functional outcome at 1 month. Potentially modifiable risk factors for increased blood pressure variability include low urinary sodium excretion.

Baseline knowledge about hypertension and sociodemographic factors related to salt intake behavior among hypertensive individuals in a rural community of Bangladesh: Substudy of a randomized controlled trial.

Excess salt consumption increases blood pressure, and therefore, this substudy was designed among rural hypertensive individuals to assess the baseline knowledge about hypertension (HTN), and dietary salt intake behavior and identify the potential predictors for urinary salt excretion in Bangladesh. A total of 420 participants were enrolled after meeting the eligibility criteria during the 12 months of the study period. The participants received behavior changes related to short message services (SMS) and face-to-face education from community health workers. Our study results found that 80% of the participants had positive knowledge of HTN. This study showed that the mean value of overnight urinary sodium excretion was 10.65 ± 3.00 at the 1st-month follow-up and 10.24 ± 3.03 at the endline. We found that mid-upper arm circumference (MUAC), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were significantly related to higher salt intake (P = 0.009, P = 0.011, and P = 0.005, respectively). However, participants had improved their MUAC, SBP, and DBP status in their 1st follow-up period, but still, significant associations were observed between them (P = 0.033, P = 0.011, and P = 0.002, respectively). This study's results found that sodium excretion among hypertensive participants was higher, and higher urinary sodium excretion was associated with overweight and BP in adults. Nonetheless, the real salt intake practice among the Bangladeshi population is still unknown, which demands further research.

Renoprotective effects of genetically proxied fibroblast growth factor 21: Mendelian randomization, proteome-wide and metabolome-wide association study

BackgroundFibroblast growth factor 21 (FGF21) has demonstrated efficacy for reducing liver fat and reversing non-alcoholic steatohepatitis in phase 2 clinical trials. It is also postulated to have anti-fibrotic effects and therefore may be amenable to repurposing for the prevention and treatment of chronic kidney disease (CKD). MethodsWe leverage a missense genetic variant, rs739320 in the FGF21 gene, that associates with magnetic resonance imaging-derived liver fat as a clinically validated and biologically plausible instrumental variable for studying the effects of FGF21 analogs. Performing Mendelian randomization, we ascertain associations between instrumented FGF21 and kidney phenotypes, cardiometabolic disease risk factors, as well as the circulating proteome (Somalogic, 4907 aptamers) and metabolome (Nightingale platform, 249 metabolites). ResultsWe report consistent renoprotective associations of genetically proxied FGF21 effect, including higher glomerular filtration rates (p = 1.9 × 10−4), higher urinary sodium excretion (p = 5.1 × 10−11), and lower urine albumin-creatinine ratio (p = 3.6 × 10−5). These favorable effects translated to lower CKD risk (odds ratio per rs739320 C-allele, 0.96; 95%CI, 0.94–0.98; p = 3.2 × 10−4). Genetically proxied FGF21 effect was also associated with lower fasting insulin, waist-to-hip ratio, blood pressure (systolic and diastolic BP, p < 1.0 × 10−07) and blood lipid (low-density lipoprotein cholesterol, triglycerides and apolipoprotein B, p < 6.5 × 10−24) profiles. The latter associations are replicated in our metabolome-wide association study. Proteomic perturbations associated with genetically predicted FGF21 effect were consistent with fibrosis reduction. ConclusionThis study highlights the pleiotropic effects of genetically proxied FGF21 and supports a re-purposing opportunity for the treatment and prevention of kidney disease specifically. Further work is required to triangulate these findings, towards possible clinical development of FGF21 towards the treatment and prevention of kidney disease.

Proteinuria Modifies the Relationship Between Urinary Sodium Excretion and Adverse Kidney Outcomes: Findings From KNOW-CKD

High sodium intake is associated with increased proteinuria. Herein, we investigated whether proteinuria could modify the association between urinary sodium excretion and adverse kidney outcomes in patients with chronic kidney disease (CKD). In this prospective observational cohort study, we included 967 participants with CKD stages G1 to G5 between 2011 and 2016, who measured 24-hour urinary sodium and protein excretion at baseline. The main predictors were urinary sodium and protein excretion levels. The primary outcome was CKD progression, which was defined as a≥50% decline in the estimated glomerular filtration rate (eGFR) or the onset of kidney replacement therapy. During a median follow-up period of 4.1 years, the primary outcome events occurred in 287 participants (29.7%). There was a significant interaction between proteinuria and sodium excretion for the primary outcome (P= 0.006). In patients with proteinuria of<0.5 g/d, sodium excretion was not associated with the primary outcome. However, in patients with proteinuria of≥0.5 g/d, a 1.0 g/d increase in sodium excretion was associated with a 29% higher risk of adverse kidney outcomes. Moreover, in patients with proteinuria of≥0.5 g/d, the hazard ratios (HRs) (95% confidence intervals[CIs]) for sodium excretion of<3.4 and≥3.4 g/d were 2.32 (1.50-3.58) and 5.71 (3.58-9.11), respectively, compared with HRs for patients with proteinuria of<0.5 g/d and sodium excretion of<3.4 g/d. In sensitivity analysis with 2 averaged values of sodium and protein excretion at baseline and third year, the results were similar. Higher urinary sodium excretion was more strongly associated with an increased risk of adverse kidney outcomes in patients with higher proteinuria levels.

PS-C35-5: URINARY SODIUM EXCRETION AND THE RISK OF CARDIOVASCULAR DISEASE: A COMMUNITY-BASED COHORT STUDY IN TAIWAN

Urinary sodium excretion is a potential risk factor for cardiovascular diseases (CVD). However, the underlying biological mechanisms and effects of salt sensitivity are unclear. The purpose of this study was to characterize the relative contribution of biological factors to the sodium-CVD association. A total of 2112 participants were enrolled in this study. Structured questionnaires and blood and urine samples were obtained. Twenty-four-hour sodium excretion was estimated using a single overnight urine sample. Hypertension, metabolic syndrome, and overweight status were considered to indicate salt sensitivity. Cox proportional hazard models were used to investigate the effects of salt sensitivity on urinary sodium excretion and CVD risk. The traditional mediation approach was used to calculate the proportion of mediation. The mean age (standard deviation) of the 2112 participants was 54.5 (12.2) years, and they were followed up for a mean of 14.1 [8.1] years. Compared with those in the lowest quartile, the highest baseline urinary sodium excretion (&gt; 4.2 g/24 hours) was associated with a 43% higher CVD risk (hazard ratio, 1.43; 95% confidence interval, 1.02–1.99). Participants with high urinary sodium excretion, hypertension, or metabolic syndrome had a significantly high risk of CVD. The carotid intima-media thickness had the largest mediating effect (accounting for 35% of the sodium-CVD association), followed by systolic blood pressure (33%), left ventricular mass (28%), and diastolic blood pressure (14%). Higher urinary sodium excretion increased the risk of CVD, which was explained largely by carotid media-thickness and systolic blood pressure.

PS-C35-2: BASELINE KNOWLEDGE AND SOCIODEMOGRAPHIC FACTORS RELATED TO SALT-INTAKE BEHAVIOR AMONG HYPERTENSIVE INDIVIDUALS IN BANGLADESH: SUB-STUDY OF A RANDOMIZED CONTROLLED TRIAL

Excess salt consumption increases blood pressure which is a leading risk for developing cardiovascular diseases. Therefore, this sub-study was designed among the rural hypertensive individuals to assess the baseline knowledge about hypertension, dietary salt intake behavior and identify the potential predictors for urinary salt excretion in Bangladesh. A total of 420 participants were enrolled after meeting the eligibility criteria during the 12 months of the study period. The participants received behavior changes related to short message services (SMS) and face-to-face education from community health workers. Our study results found that most of the participants (80%) had positive knowledge of HTN. This study showed that the mean value of overnight urinary sodium excretion was 10.65 ± 3.00 at 1st-month follow-up and 10.24 ± 3.03 at the endline. We found mid-upper arm circumference (MUAC) systolic blood pressure (SBP), and diastolic blood pressure (DBP) were significantly related to higher salt-intake (p = 0.009, p = 0.011 and p = 0.005 respectively). However, participants had improved their MUAC, SBP, and DBP status than their 1st follow-up period, but still, significant associations were observed between them (p = 0.033, p = 0.011, and p = 0.002 respectively). In conclusion, most of our study participants had satisfactory knowledge related to HTN and salt intake. Besides, our study results found that sodium excretion among hypertensive participants was higher, and higher urinary sodium excretion was associated with overweight and BP in adults. Nonetheless, the real salt intake practice among the Bangladeshi population is still unknown which demands further research.

ODP270 Prevalence of Primary Hyperaldosteronism in Patients with Resistant Hypertension - An Outpatient Cross-Sectional Clinic-Based Study

Abstract Background Primary hyperaldosteronism is the non-suppressible over secretion of aldosterone caused either by an adenoma or bilateral adrenal hyperplasia. Although its reported prevalence is 8-10% in recent studies, intraindividual variability for aldosterone levels poses diagnostic challenges during the screening of these patients. In this study, we aim to assess the prevalence of primary hyperaldosteronism in patients presenting with drug-resistant hypertension, with or without hypokalemia, at a general endocrinology practice with an emphasis on the variability of renin and aldosterone levels in the screening tests used to detect primary hyperaldosteronism. Method: We included participants presenting at our outpatient clinic from June 2020 until January 2022 with blood pressure&amp;gt;140/90mm Hg despite the use of three antihypertensive medications including a diuretic. The screening tests used were morning (8-9 AM) plasma aldosterone concentration (PAC) and plasma renin (PR) level. Aldosterone was measured using L iquid Chromatography-Tandem Mass Spectrometry assay determined by Mayo Clinic. The screening was considered positive when PAC was&amp;gt;10 ng/dL (277 pmol/l) and PR was &amp;lt;1 ng/ml/hr. The tests were repeated if PAC was between 5-10 ng/dL and PR was between 1-2 ng/ml/hr without any medication changes. If the repeat PR was &amp;gt;2 ng/ml/hr, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers were stopped and changed to calcium channel blockers, and the patient was tested again after 2 weeks. Positive results were further tested with 24-hour urinary aldosterone excretion during high dietary salt ingestion with 24-hour urine sodium and creatinine. Primary hyperaldosteronism was confirmed if plasma renin activity was &amp;lt;1. 0 ng/mL per hour and urinary aldosterone was &amp;gt;12 mcg/24-hour during high urinary sodium excretion (&amp;gt;200 mEq/24-hour). Results We studied a total of 138 patients during this study period. Mean age was 58.7 years and BMI 33.7 kg/m 2, out of which 95 participants had type 2 diabetes mellitus, 7 had obstructive sleep apnea, and 20 had chronic kidney disease stage 3 or higher. We found 3 patients were positive on screening tests and two patients were confirmed to have primary hyperaldosteronism, making prevalence 2/138(1.45%). Conclusion Hyperaldosteronism is the most common cause of secondary hypertension, especially resistant hypertension. Repeat testing of aldosterone levels with intraindividual variability can be very challenging, and time-consuming resulting in repeated follow-up visits and multiple communications with providers posing challenges for effective care coordination, and financial burden on patients. Further large-scale studies are recommended to re-analyze the protocols for screening hyperaldosteronism and treatment initiation without extensive confirmatorytesting. We also suggest health care providers emphasize on effective management of other secondary causes of hypertension such as obesity and Metabolic Syndrome with diabetes for a greater impact on blood pressure control on these patients. Presentation: No date and time listed

Urinary Sodium Excretion Enhances the Effect of Alcohol on Blood Pressure.

Alcohol consumption is linked to urinary sodium excretion and both of these traits are linked to hypertension and cardiovascular diseases (CVDs). The interplay between alcohol consumption and sodium on hypertension, and cardiovascular diseases (CVDs) is not well-described. Here, we used genetically predicted alcohol consumption and explored the relationships between alcohol consumption, urinary sodium, hypertension, and CVDs. Methods: We performed a comparative analysis among 295,189 participants from the prospective cohort of the UK Biobank (baseline data collected between 2006 and 2010). We created a genetic risk score (GRS) using 105 published genetic variants in Europeans that were associated with alcohol consumption. We explored the relationships between GRS, alcohol consumption, urinary sodium, blood pressure traits, and incident CVD. We used linear and logistic regression and Cox proportional hazards (PH) models and Mendelian randomization in our analysis. Results: The median follow-up time for composite CVD and stroke were 6.1 years and 7.1 years respectively. Our analyses showed that high alcohol consumption is linked to low urinary sodium excretion. Our results showed that high alcohol GRS was associated with high blood pressure and higher risk of stroke and supported an interaction effect between alcohol GRS and urinary sodium on stage 2 hypertension (Pinteraction = 0.03) and CVD (Pinteraction = 0.03), i.e., in the presence of high urinary sodium excretion, the effect of alcohol GRS on blood pressure may be enhanced. Conclusions: Our results show that urinary sodium excretion may offset the risk posed by genetic risk of alcohol consumption.

Study on the Correlation between Urinary Sodium and Potassium Excretion and Blood Pressure in Adult Hypertensive Inpatients of Different Sexes

Objective This study aims to understand the difference in the influence of urinary sodium and potassium excretion on blood pressure in patients of different sexes with hypertension by analyzing the relationship between urinary sodium and potassium excretion and blood pressure. Methods In this cross-sectional study, 606 hospitalized patients with essential hypertension were recruited from 16 hospitals in the Shanxi Province between June 2018 and December 2019. These patients were grouped by sex, with 368 males and 238 females. Basic information and relevant serum biochemical indexes of patients in the two groups were recorded. The 24-hour urinary sodium and potassium excretion were measured, and 24-hour ambulatory blood pressure monitoring was performed simultaneously. This was done to analyze and compare the relationship between urinary sodium and urinary potassium excretion and blood pressure in adult hospitalized patients of different sexes with hypertension. Results The 24-hour urinary sodium excretion in male patients with hypertension was significantly higher than that in female patients (P < 0.001). There was no significant difference in 24-hour urinary potassium excretion between male patients with hypertension and female patients. Spearman correlation analysis showed that 24-hour urinary sodium excretion was positively correlated with 24-hour SBP and nSBP in male patients (P < 0.05), while 24-hour urinary potassium excretion was negatively correlated with 24-hour SBP and nSBP in male patients (P < 0.05). The 24-hour urinary sodium in female patients was significantly positively correlated with 24-hour SBP, 24-hour DBP, SBP, dDBP, nSBP, and nDBP (P < 0.01). The 24-hour urinary potassium was significantly negatively correlated with nSBP (P < 0.05). Multiple stepwise linear regression showed that 24-hour urinary sodium excretion was still significantly positively correlated with 24-hour SBP and nSBP in male patients with hypertension after adjusting for various confounding factors. Conclusion High urinary sodium and low urinary potassium excretion are closely related to elevated blood pressure in adult patients with hypertension, and there are sex differences.

Salt-Sensitive Hypertension of the Renal Tubular Cell-Specific NFAT5 (Nuclear Factor of Activated T-Cells 5) Knockout Mice.

[Figure: see text].

Association of Urinary Sodium Excretion and Left Ventricular Hypertrophy in People With Type 2 Diabetes Mellitus: A Cross-Sectional Study

BackgroundIt has been well documented that left ventricular hypertrophy (LVH) is highly associated with the incidence of cardiovascular disease (CVD). Evidence indicated that high sodium intake was closely related with LVH in general population. However, information is not available regarding the association between urinary sodium excretion and LVH in patients with type 2 diabetes mellitus (T2DM). This study aimed to explore the association between urinary sodium excretion and LVH in patients with T2DM.MethodsThis cross-sectional analysis included baseline data from 1,556 individuals with T2DM enrolled in the NanFang Prospective Diabetes Study (NFPDS). Urinary sodium excretion levels were measured from 24-hour urine samples of inpatients and morning fasting urine samples of outpatients. Left ventricular dimensions were assessed by echocardiography. The associations between urinary sodium excretion and the risks of cardiovascular events, LVH and left ventricular mass index (LVMI) were examined using linear regression analysis, logistic regression and restricted cubic splines (RCS).ResultsUrinary sodium excretion levels were positively associated with cardiometabolic risk factors, including systolic blood pressure, body mass index, waist circumference and LVMI (All P<0.001). Odds ratios of the highest quartile of urinary sodium excretion compared with the lowest quartile were 1.80 (95% CI, 1.28-2.54; P=0.001) for LVH and 1.77 (95% CI, 1.06-2.94; P=0.028) for CVD, after adjusted for demographics, lifestyle risk factors and cardiovascular risk factors. Multivariable-adjusted RCS analysis of the association between urinary sodium excretion and LVMI showed a significant association (P=0.001) and lacked evidence of a nonlinear association (P=0.406).ConclusionThis study indicated that high urinary sodium excretion was independently associated with increased risk of LVH and CVD in patients with T2DM, suggesting that control of sodium intake may be valuable for the prevention of diabetic cardiovascular complications.

Association of urinary sodium excretion with fluid overload in patients with chronic kidney disease

Objective: To investigate the relationship between urinary sodium excretion and fluid overload (FO) in non-dialysis patients with chronic kidney disease (CKD). Methods: Patients with CKD stage 1-4 who underwent bioelectrical impedance (BIA) in the Department of Nephrology, Jiangsu Province Hospital from December 2019 to January 2021 were recruited. All enrolled patients were categorized into two groups according to whether or not they develop FO. Further, clinical parameters were compared between the two groups. Spearman correlation analysis was used to investigate the association between over hydration/extracellular water (OH/ECW) and clinical characteristics. Multivariate logistic regression analysis was performed to evaluate the relationship between urinary sodium excretion and FO (FO was defined as OH/ECW≥7%). Results: A total of 385 patients with CKD stage 1-4 were finally included in the study, with a mean age of (46±15) years. There were 216 male cases (56.1%), and 150 cases (39.0%) existed FO. Spearman correlation analysis indicated that OH/ECW positively correlated with urinary sodium excretion (r=0.147, P=0.004), urinary protein excretion (r=0.555, P<0.001) and systolic blood pressure (r=0.241, P<0.001), but inversely related to estimated glomerular filtration rate (eGFR) (r=-0.111, P=0.030) and serum albumin (r=-0.659, P<0.001). After adjusting for confounding factors including age, systolic blood pressure, diabetes, urinary protein excretion, serum albumin, serum sodium, serum chlorine, urinary calcium excretion, urinary phosphorus excretion and use of diuretics, multivariate logistic regression analysis demonstrated that higher level of urinary sodium excretion was associated with increased risk of FO in patients with CKD (OR=1.005, 95%CI: 1.000-1.011, P=0.048). Conclusion: High urinary sodium excretion is independently associated with fluid FO in non-dialysis patients with CKD.

EFFECTS OF DAPAGLIFLOZIN IN HIGH AND LOW DIETARY SALT INTAKE PATIENTS WITH ALBUMINURIC DIABETIC KIDNEY DISEASE: A SUBANALYSIS OF THE Y-AIDA STUDY

Objective: Current guidelines recommend the intensive control of BP as well as blood glucose to reduce albuminuria and prevent the development of diabetic kidney disease (DKD). We reported that improved home BP profile with dapagliflozin is independently associated with amelioration of albuminuria in Japanese patients with DKD (Kinguchi, et al. Cardiovasc Diabetol. 2019). The aim of this subanalysis was to investigate the differences in home BP lowering effects between high and low dietary salt intake patients with albuminuric DKD. Design and method: The Yokohama Add-on Inhibitory efficacy of Dapagliflozin on Albuminuria in Japanese patients with type 2 diabetes (Y-AIDA) study was a prospective, multicenter, single-arm study. A total of 86 T2DM (HbA1c 7.0–10.0%) individuals with albuminuric DKD (UACR &gt; = 30 mg/gCr, eGFR &gt; = 45 ml/min/1.73m2) were enrolled, and 85 participants were administered with add-on dapagliflozin for 24 weeks. Subgroup analysis, in which patients were classified into 2 groups according to their urinary sodium excretion at baseline, was conducted to determine the change from baseline in home BP profile at week 24. Results: At baseline, office systolic BP and morning, evening, and nocturnal home systolic BP were comparable between high urinary sodium excretion group (high group) and low urinary sodium excretion group (low group) (144.0 ± 19.7 vs 140.4 ± 18.4, P = 0.4044; 138.5 ± 12.1 vs 136.4 ± 16.6, P = 0.5179; 137.4 ± 17.6 vs 134.4 ± 17.3, P = 0.4481; 124.7 ± 14.8 vs 125.9 ± 14.9, P = 0.7267). The change in evening home systolic BP was greater in high group than in low group (-13.1 ± 12.0 vs -6.4 ± 11.4, P = 0.0203). The change in office BP, and morning and nocturnal home BP were comparable between high group and low group. Conclusions: In albuminuric DKD patients who have high dietary salt intake, add-on dapagliflozin treatment resulted in a greater decrease in evening home BP than in those who have low dietary salt intake.

Twenty four-hour urine collection is appropriate in a cohort of South African renal stone formers

Objectives: To report the prevalence of metabolic abnormalities found in an urban South African population of stone formers and thereby determine whether international guidelines on 24-hour urine collection should be recommended for South African stone formers.Methods: A retrospective folder review was conducted on patients who were admitted with renal stones or who had renal stone procedures between 1 November 2014 and 31 March 2020, with a confirmed history of renal calculi and who had 24-hour urine collection at a tertiary centre renal stone clinic. All confirmed stone formers were offered 24-hour urine collection once they were infection-free and stone-free. Demographics, 24-hour urine collection findings and stone analysis results (if available) were recorded. A 24-hour urine collection was performed once patients were stone-free while on their regular diet and routine lifestyle.Results: 175 patients with metabolic studies were included (65 females and 110 males). The mean age was 53.8 ±13.6 years. The commonest metabolic risk factors were hypocitraturia (61.0%), hypomagnesiuria (41.1%), mild hypercalciuria (22.0%), and hyperuricosuria (20.2%). Hyperuricaemia, high urinary sodium excretion, mild hypercalciuria and hyperuricosuria were more common in men. A total of 102 patients had both 24-hour urine collection and stone analysis for comparison. There were no differences between different stone types in the prevalence of metabolic risk factors except for hyperuricaemia and high urinary sodium excretion, which were both higher in uric acid predominant stone formers.Conclusion: The prevalence of risk factors was high and seemed similar to that of other populations, except for a higher prevalence of hypocitraturia. Internationally recommended guidelines for 24-hour urine studies are therefore applicable and appropriate for this population. Risk factors seem similar across stone types; however, a larger study is necessary to clarify whether metabolic risk factors are useful to predict stone composition.

Renal salt wasting syndrome in a patient with COVID-19; a case report and review of the literature

Introduction: Cerebral salt wasting or renal salt wasting (RSW) syndrome, may be more common than syndrome of inappropriate antidiuretic hormone secretion (SIADH) and may even occur in the absence of cerebral disease. We report a case of RSW in a Bangladeshi patient positive for COVID-19 without clinical cerebral disease. Case Presentation: A 53 years-old Bangladeshi patient presented with history of chest pain and acute MI. On examination, the patient was conscious, alert, vitally stable, chest with fine bilateral basal crepitation and heart with additional S3 sound and abdomen was lax with no organomegaly. There was no lower limbs oedema. His serum creatinine; 68 umol/L, urea; 3.4 mmol/L, K; 4.7 mmol/L, sodium; 135 mmol/L, uric acid; 141 mmol/L and phosphate was 1.3 mmol./L. Echocardiography (ECG) revealed anterior lateral wall STEMI. PCI was done for LAD. ECG revealed ejection fraction (EF) 10-15 %. Nasopharyngeal swab for COVID-19 was positive. Serum sodium decreased from 135 to 108 with signs of hypovolemia. Work up for hyponatremia revealed serum osmolality of 237 mOsm/kg, urine NA; 109 mmol/L, urine osmolality; 295 mOsm/kg, urine uric acid; 685 umol/L, and urine phosphate; 6.5 mmol/L. Additionally serum T3, T4, TSH and serum basal cortisol were normal. The patient received normal saline infusion and fludrocortisone and serum sodium increased to 134 mmol/L. Our patient had all the important clinical and laboratory characteristics of RSW in the absence of cerebral disease which include hyponatremia associated with hypovolemia, high urinary sodium excretion, increased fraction excretion of phosphate and persistent hypouricemia with increased fractional excretion of urate after correction of hyponatremia and with normal renal, adrenal and thyroid functions. Furthermore, there was a prompt response to saline replacement and fludrocortisone and steady improvement in serum sodium with negativity and improvement of COVID-19. Our diagnosis was RSW in the absence of cerebral disease and to our knowledge; this is the first case of RSW in a patient with COVID-19 in the literature. Conclusion: RSW should be considered in patients with COVID-19 with hyponatremia and absence of cerebral disease. We suggest changing cerebral salt wasting to the more appropriate term RSW.

Urinary Sodium-to-Potassium Ratio and Blood Pressure in CKD

IntroductionIn the general population, urinary sodium-to-potassium (uNa/K) ratio associates more strongly with high blood pressure (BP) than either urinary sodium or potassium alone. Whether this is also the case among patients with chronic kidney disease (CKD) is unknown.MethodsWe studied the associations of spot urine sodium-to-creatinine (uNa/Cr), potassium-to-creatinine (uK/Cr), and uNa/K ratios with a single office BP reading in 1660 patients with moderate to severe CKD at inclusion in the CKD-REIN cohort.ResultsPatients' median age was 68 (interquartile range [IQR], 59–76) years; most were men (65%), had moderate CKD (57%), and albuminuria (72%). Mean systolic and diastolic BP was 142/78 mm Hg. Spot uNa/Cr and uNa/K ratios were positively associated with systolic, mean arterial, and pulse pressures. The mean adjusted difference in systolic BP between the highest and the lowest quartile (Q4 vs. Q1) was 4.24 (95% confidence interval [CI], 1.53–6.96) mm Hg for uNa/Cr and 4.79 (95% CI, 2.18–7.39) mm Hg for uNa/K. Quartiles of spot uK/Cr were not associated with any BP index. The higher the quartile of uNa/K, the higher the prevalence ratio of uncontrolled (Q4 vs. Q1, 1.43; 95% CI, 1.19–1.72) or apparently treatment-resistant hypertension (Q4 vs. Q1, 1.35; 95% CI, 1.14–1.60). Findings were consistent in a subset of 803 individuals with 2 BP readings.ConclusionIn patients with CKD, higher urinary sodium excretion is associated with higher BP, but unlike in general population, lower potassium excretion is not. Urinary Na/K does not add significant value in assessing high BP risk, except perhaps for hypertension control assessment.

The effect of uric acid and urinary sodium excretion on prehypertension: a nationwide population-based study

BackgroundThis study examined the effect of serum uric acid (SUA) level and urinary sodium excretion on blood pressure as well as their combined effect on prehypertension in a Korean population.MethodData from the 7th Korea National Health and Nutrition Examination Survey for adults (≥ 19 years of age) were used. The participants were classified into two groups, normotension and prehypertension, according to the JNC-7 definition. Logistic regression was carried out and adjusted for traditionally regarded confounders of blood pressure. All analyses considered a complex sampling design. A multivariate analysis was performed on subgroups defined according to their SUA level and urinary sodium excretion.ResultsThe 4200 participants were divided into normotension (n = 2646) and prehypertension (n = 1554) groups. In the univariate analysis, patient age, male sex, concurrent comorbidity (diabetes mellitus, cardiovascular disease, stroke, dyslipidemia, and chronic kidney disease), uric acid, and urinary sodium excretion were associated with prehypertension. After adjusting for baseline covariates, both the SUA level and urinary sodium excretion were significant predictors of incident prehypertension (SUA, per 1 mg/dL increase, odds ratio [OR] 1.216, 95% confidence interval [95% CI] 1.131–1.309; urinary sodium excretion, per 1 g/day increase, OR 1.067, 95% CI 1.019–1.117). Additionally, simultaneously higher tertiles of SUA and urinary sodium excretion resulted in higher ORs for prehypertension.ConclusionIncreased SUA is a significant risk marker for the development of prehypertension in normotensives. Simultaneously high SUA and urinary sodium excretion amplified the effect on the development of prehypertension. Our findings suggest that lowering SUA levels and reducing sodium intake will contribute to preventing hypertension.

Hyperinsulinemia rather than insulin resistance itself induces blood pressure elevation in high fat diet-fed rats

ABSTRACT Objective To investigate if insulin resistance per se or the accompanying hyperinsulinemia induced hypertension and its underlying mechanisms. Methods Sprague-Dawley rats were randomized into normal diet-fed group (ND group) and high-fat diet-fed group (HFD group). Then, the HFD group was further randomly divided into the control group (HFD_C group), the PIO group (treated with pioglitazone), the STZ_DM group (to induce diabetes with streptozotocin) and the DM+Ins group (streptozotocin injection followed by insulin treatment). Insulin sensitivity, plasma insulin, endothelin-1, norepinephrine, aldosterone, angiotensinⅡ and 24-h urinary sodium excretion (USE) levels of the groups were measured and analyzed. A multiple stepwise regression analysis method was applied to exam our hypothesis. Results Compared to HFD_C group, the groups with lower plasma insulin, the PIO group and STZ_DM group, showed higher USE and lower blood pressure. The groups with higher plasma insulin (but same level of insulin resistance), the HFD_C group and DM+Ins group, showed lower USE and higher blood pressure. The 24-h urinary sodium excretion was the most important contributor to the significant changes of blood pressure with an R2 of 25.2% in this animal experiment. Conclusions It is the compensatory hyperinsulinemia rather than insulin resistance per se that causes blood pressure elevation. The urinary sodium excretion is the key mediator among the multiple mechanisms. Therapies targeting hyperinsulinemia and restricting salt intake may favor a better control of hypertension associated with insulin resistance.

Factors Influencing Low Sodium Intake in People with Non-Dialysis Dependent Chronic Kidney Disease.

To evaluate dietary sodium intake in people with chronic kidney disease (CKD) and identify contributing factors to low sodium intake by applying the Theory of Planned Behaviour (TPB) framework. Non-dialysed people with CKD completed a 24-hour urinary sodium excretion test and Scored Salt Questionnaire (SSQ). A survey including socio-demographic information, Brief Illness Perception Questionnaire, Short Sodium Knowledge Survey and Dietary Sodium Restriction Questionnaire based on TPB measured the factors contributing to dietary adherence. Sixty-three people [age: 71 (IQR: 64-77); 27% female] participated with 80% having high urinary sodium excretion [median: 134 mmol/day (111; 183)] but only 40% reported high sodium intake [SSQ score = 53 (39; 75)]. Overall sodium knowledge was high in 57% of participants although only 33% had seen a dietitian. There was a positive correlation between attitude towards a low-sodium diet and subjective norm (social expectations), r = 0.44, p < 0.01; urinary sodium and the extent of perceived consequences of CKD (r = 0.26, p < 0.05); and the extent to which willpower was perceived as a barrier to adherence to dietary sodium restriction (r = 0.27, p < 0.05). Multiple regression analysis revealed taste of low-salt foods (β = 8.9, p < 0.01) explained 26.4% of variance in dietary sodium intake (R2 = 0.264, F(12, 34), p < 0.01). TPB successfully identified barriers to follow a low-sodium diet in non-dialysed people with CKD. Taste preferences, willpower, meeting social expectations and disease concern were identified as key contributing factors to adherence.