Comparison of the performance of currently used estimated glomerular filtration rate equations with 24-hour urine creatinine clearance: sample analysis of randomised controlled trial participants.

OBJECTIVE: There are several equations for estimating the glomerular filtration rate (GFR), and each method has its limitations. We compared various estimated GFR (eGFR) equations with 24 hours urine creatinine clearance (24u-CCr). DESIGN: Sample analysis of randomised controlled trial participants. SETTING AND PARTICIPANTS: We compared the mean 24u-CCr values measured 2-3 times for 211 patients with eGFR values calculated using the following equations: isotope dilution mass spectrometry-Modification of Diet in Renal Disease (IDMS-MDRD) equation, Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, equations for Koreans (KOR-IDMS-MDRD and KOR-CKD-EPI) and full age spectrum equation. OUTCOME MEASURES: Performance of various creatinine-based eGFR equations, including those with Korean coefficients, compared with the results of the 24u-CCr. RESULTS: IDMS-MDRD showed the best overall correlation with the 24u-CCr (R=0.949, p<0.001), and KOR-CKD-EPI showed the best agreement in terms of the intraclass correlation coefficient (ICC, 0.969, 95% CI 0.959 to 0.976, p<0.001). In subgroup analysis, IDMS-MDRD-GFR showed the highest ICCs in CKD stages 1 and 3 (ICC 0.872 in stage 1 and 0.927 in CKD stage 3, all p<0.001). KOR-CKD-EPI showed the highest ICC in CKD stage 2 (ICC 0.854, p<0.001). Overall, the accuracy of CKD-EPI (2021) was the highest at P15 (15%) and P30 (30%) (P15: 65.4 and P30: 97.6). In addition, CKD-EPI (2021) showed the highest P30 accuracy in CKD stage 1 (98.7), whereas KOR-IDMS-MDRD showed the highest P30 accuracy in CKD stages 2 and 3 (98.8 and 98.2, respectively). CONCLUSIONS: The IDMS-MDRD equation showed the best correlation and overall good agreement with the 24u-CCr; however, the accuracy was low. The most accurate measurements were obtained using the CKD-EPI (2021) equation in CKD stage 1 and the KOR-IDMS-MDRD equation in CKD stages 2-3; nevertheless, the CKD-EPI (2021) equation showed the best overall accuracy. TRIAL REGISTRATION NUMBER: NCT01552954.

Effects of Sustained-Release Beraprost in Patients With Primary Glomerular Disease or Nephrosclerosis: CASSIOPEIR Study Results.

TRK-100STP, a sustained-release preparation of the orally active prostacyclin analogue beraprost sodium, targets renal hypoxia. This study aimed to show the superiority of TRK-100STP over placebos in patients with chronic kidney disease (with either primary glomerular disease or nephrosclerosis) to determine the recommended dose. CASSIOPEIR (Chronic Renal Failure Asian Study with Oral PGI2 Derivative for Evaluating Improvement of Renal Function) was a randomized, double-blind, placebo-controlled study conducted at 160 sites in seven Asia-Pacific countries and regions. Eligible patients (n = 892) were randomized to TRK-100STP 120, 240 µg, or placebo for a treatment period of up to 4 years. The primary efficacy endpoint was time to first occurrence of a renal composite: doubling of serum creatinine or occurrence of end-stage renal disease. No significant differences were observed in composite endpoints between TRK-100STP and placebo (P = 0.5674). Hazard ratios (95% CI) in the TRK-100STP 120 and 240 µg vs. placebo groups were 0.98 (0.78, 1.22) and 0.91 (0.72, 1.14), respectively. The overall incidence of adverse events and adverse drug reactions was comparable between treatment arms.

Weight loss has an additive effect on the proteinuria reduction of angiotensin II receptor blockers in hypertensive patients with chronic kidney disease.

BACKGROUND: Weight reduction is a lifestyle intervention that has been introduced for prevention and management of chronic kidney disease (CKD). We investigate the additive anti-proteinuric effect of weight reduction on the usage of angiotensin II receptor blockers (ARBs) and its potential mechanisms in hypertensive CKD patients. METHODS: This study is a subanalysis of data from an open-label, randomized, controlled clinical trial. Among the 235 participants, 227 were assigned to subgroups according to changes in body weight. RESULTS: Fifty-eight participants (25.6%) were assigned to group 1 (≥1.5% decrease in body weight after 16 weeks), 32 participants (14.1%) were assigned to group 2 (1.5-0.1% decrease in body weight), and 136 participants (59.9%) were assigned to group 3 (≥ 0.0% increase in body weight). Characteristics at enrollment were not different among the three groups, but mean differences in weight and percent changes in urinary sodium excretion over the period were statistically different (P < 0.001 and P = 0.017). Over the study period, unintentional weight loss independently increased the probability of reduced albuminuria (group 1, relative risk 6.234, 95% confidence interval 1.913-20.315, P = 0.002). Among urinary cytokines, only podocalyxin level decreased significantly in participants who lost weight (P = 0.013). CONCLUSION: We observed that weight loss had an additive effect on the anti-proteinuric effects of ARBs in nondiabetic hypertensive CKD patients, although it was minimal. An additive effect was shown in both obese and non-obese participants, and its possible mechanism is related to reduction of podocyte damage.

Associations of urinary sodium levels with overweight and central obesity in a population with a sodium intake.

BACKGROUND: Previous studies have reported an association between dietary sodium intake and overweight/central obesity. However, dietary survey methods were prone to underestimate sodium intake. Therefore, this study investigated the associations of calculated 24-h urinary sodium excretion, an index of dietary sodium intake, with various obesity parameters including body mass index (BMI) and waist circumference (WC) in a population with a relatively high sodium intake. METHODS: A total of 16,250 adults (aged ≥19 years) and 1476 adolescents (aged 10-18 years), with available information on spot urine sodium levels and anthropometric measurements from the Korea National Health and Nutrition Examination Survey (KNHANES) were included in this study. We calculated 24-h urine sodium excretion levels from spot urine sodium levels using the Tanaka formula. RESULTS: In adults, those with high sodium excretion levels (≥ 3200 mg) showed increased odds of overweight and central obesity compared to those with low urinary sodium excretion level (< 2200 mg) (odds ratio [OR] = 2.17, 95% confidence interval [CI] = 1.90-2.49 for overweight; OR = 2.50, 95% CI = 2.13-2.94 for central obesity). These associations were also observed in adolescents (OR = 5.80, 95% CI = 3.17-10.60 for overweight; OR = 4.19, 95% CI = 1.78-9.89 for central obesity). CONCLUSIONS: The present study suggests that reducing salt intake might be important for preventing overweight and central obesity, especially in adolescents. However, because the present study was conducted with cross-sectional study design, further longitudinal studies are warranted to confirm the causal relationship between urinary sodium excretion and overweight/central obesity.

Estimating the urinary sodium excretion in patients with chronic kidney disease is not useful in monitoring the effects of a low-salt diet.

BACKGROUND: Several epidemiologic studies have suggested that the urine sodium excretion (USE) can be estimated in lieu of performing 24-hour urine collection. However, this method has not been verified in patients with chronic kidney disease (CKD) or in an interventional study. The purpose of this study was to evaluate the usefulness of estimating USE in a prospective low-salt diet education cohort (ESPECIAL). METHODS: A new formula was developed on the basis of morning fasting urine samples from 228 CKD patients in the ESPECIAL cohort. This formula was compared to the previous four formulas in the prediction of 24-hour USE after treatment with olmesartan and low-salt diet education. RESULTS: Most previously reported formulas had low predictability of the measured USE based on the ESPECIAL cohort. Only the Tanaka formula showed a small but significant bias (9.8 mEq/day, P < 0.05) with a low correlation (r = 0.34). In contrast, a new formula showed improved bias (-0.1 mEq/day) and correlation (r = 0.569) at baseline. This formula demonstrated no significant bias (-1.2 mEq/day) with the same correlation (r = 0.571) after 8 weeks of treatment with olmesartan. Intensive low-salt diet education elicited a significant decrease in the measured USE. However, none of the formulas predicted this change in the measured urine sodium after diet adjustment. CONCLUSION: We developed a more reliable formula for estimating the USE in CKD patients. Although estimating USE is applicable in an interventional study, it may be unsuitable for estimating the change of individual sodium intake in a low-salt intervention study.

Prophylactic effect of trimethoprim-sulfamethoxazole for pneumocystis pneumonia in patients with rheumatic diseases exposed to prolonged high-dose glucocorticoids.

OBJECTIVES: To investigate the efficacy and safety of trimethoprim/sulfamethoxazole (TMP-SMX) as primary prophylaxis for pneumocystis pneumonia (PCP) in patients with rheumatic diseases receiving high-dose steroids. METHODS: The study included 1522 treatment episodes with prolonged (≥4 weeks) high-dose (≥30 mg/day prednisone) steroids in 1092 patients over a 12-year period. Of these, 262 treatment episodes involved TMP-SMX (prophylaxis group) while other episodes involved no prophylaxis (control group). Differences in 1-year PCP incidence and its mortality between the two groups were estimated using Cox regression. To minimise baseline imbalance, propensity score matching was performed and efficacy outcome was mainly assessed in the postmatched population (n=235 in both groups). RESULTS: During a total of 1474.4 person-years, 30 PCP cases occurred with a mortality rate of 36.7%. One non-fatal case occurred in the prophylaxis group. TMP-SMX significantly reduced the 1-year PCP incidence (adjusted HR=0.07(95% CI 0.01 to 0.53)) and related mortality (adjusted HR=0.08 (95% CI 0.0006 to 0.71)) in the postmatched population. The result of the same analysis performed in the whole population was consistent with that of the primary analysis. Incidence rate of adverse drug reactions (ADR) related to TMP-SMX was 21.2 (14.8-29.3)/100 person-years. Only two serious ADRs (including one Stevens-Johnson syndrome case) occurred. The number needed to treat for preventing one PCP (52 (33-124)) was lower than the number needed to harm for serious ADR (131 (55-∞)). CONCLUSION: TMP-SMX prophylaxis significantly reduces the PCP incidence with a favourable safety profile in patients with rheumatic disease receiving prolonged, high-dose steroids.

Predialysis hyponatremia and mortality in elderly patients beginning to undergo hemodialysis.

BACKGROUND/AIMS: Predialysis hyponatremia has been recently reported to be associated with mortality in incident hemodialysis patients. However, whether hyponatremia is associated with unfavorable outcomes in elderly patients remains unknown. We hypothesized that nephrology referral inf luences hyponatremia, and aimed to define how nephrology referral affects the association between hyponatremia and mortality in the elderly. METHODS: We retrospectively assessed mortality in 599 incident hemodialysis patients aged ≥ 70 at a tertiary university hospital, between 2000 and 2010. We analyzed 90-day and 1-year all-cause mortality (ACM) in relation to predialysis serum sodium (sNa). We divided the patients into two groups according to predialysis glucose-corrected sNa: hyponatremia (< 135 mmol/L) and normonatremia (135 to 145 mmol/L). RESULTS: Low estimated glomerular filtration rate, high phosphorus, low albumin, nonpreparation of arteriovenous fistula or graft, and late referral were associated with a low sNa in the elderly. Among 599 patients, 106 and 174 patients died at the 90-day and 1-year follow-ups, respectively. Each 10-mmol/L increase in predialysis sNa tended to be associated with lower 90-day and 1-year ACM. When patients were stratified by nephrology referral, hyponatremia was associated with increased mortality in early referral group (90-day ACM: hazard ratio [HR] = 2.335, p = 0.041; 1-year ACM: HR = 1.790, p = 0.024). However, hyponatremia was not associated with mortality in late referral group. CONCLUSION: Predialysis hyponatremia at hemodialysis initiation is associated with late referra.

Association of Sodium Excretion With Metabolic Syndrome, Insulin Resistance, and Body Fat.

Sodium intake was reported to be related to metabolic syndrome (MS). Although a strong association between sodium intake and blood pressure (BP) has been reported, the relationship between sodium intake and other components of MS is unknown. An observational study of 18,146 adults in the Korea National Health and Nutrition Examination Survey IV-V databases (2008-2011) was performed. Estimates of 24-h sodium excretion were made from a single fasting urine sample. A significant positive association was found between sodium excretion and systolic BP and between sodium excretion and diastolic BP in participants with and without hypertension after adjusting for multiple covariates (P < 0.001 for trend). The relationship between triglyceride or glucose levels and sodium excretion was linear (P < 0.005). In both men and women, a positive relationship between sodium excretion and waist circumference and an inverse relationship between sodium excretion and high-density lipoprotein were found (P ≤ 0.001). Body fat percentage, body fat mass, and insulin level were positively related to sodium excretion (P ≤ 0.001), and HOMA-IR was significantly associated with sodium excretion (P < 0.05). The risk of MS was elevated 1.279-fold in the second quartile of sodium excretion (95% CI, 1.088-1.504, P = 0.003), 1.479-fold in the third quartile (95% CI, 1.262-1.734; P < 0.001), and 1.929-fold in the highest quartile (95% CI 1.654-2.249, P <  .001) compared with the lowest quartile. Sodium intake is significantly associated with all components of MS, body fat, and insulin resistance. Therefore, a high-salt diet is a significant risk factor for MS.

Effect of urine urea nitrogen and protein intake adjusted by using the estimated urine creatinine excretion rate on the antiproteinuric effect of angiotensin II type I receptor blockers.

OBJECTIVES: The aim of this study was to determine the role of protein intake on proteinuria in chronic kidney disease (CKD), as it is presently not conclusive. METHODS: This is a subanalysis of data from an open-label, case-controlled, randomized clinical trial on education about low-salt diets (NCT01552954). We estimated the urine excretion rate of parameters in a day, adjusted by using the equation for estimating urine creatinine excretion, and analyzed the effect of urine urea nitrogen (UUN), as well as estimating protein intake on the level of albuminuria in hypertensive patients with chronic kidney disease. RESULTS: Among 174 participants from whom complete 24-h urine specimens were collected, the estimates from the Tanaka equation resulted in the highest accuracy for the urinary excretion rate of creatinine, sodium, albumin, and UUN. Among 227 participants, the baseline value of estimated urine albumin excretion (eUalb) was positively correlated with the estimated UUN (eUUN) or protein intake according to eUUN (P = 0.012 and P = 0.038, respectively). We were able to calculate the ratios of eUalb and eUUN in 221 participants and grouped them according to the ratio of eUUN during 16-wk trial period. The proportion of patients that achieved a decrement of eUalb ≥25% during 16 wk with an angiotensin II type I receptor blocker (ARB) medication was 80% (24 of 30) in group 1, with eUUN ratio ≤-25%; 82.2% (111 of 135) in group 2, with eUUN ratio between -25% and 25%; and 66.1% (37 and 56) in group 3, with eUUN ratio ≥25% (P = 0.048). The probability of a decrease in albuminuria with ARB treatment was lower in patients with an increase of eUUN or protein intake during the 16 wk of ARB treatment, as observed in multiple logistic regression analysis as well. CONCLUSIONS: The estimated urine urea excretion rate showed a positive association with the level of albuminuria in hypertensive patients with chronic kidney disease. The increase of eUUN excretion ameliorated the antiproteinuric effect of ARB.

Urinary adiponectin and albuminuria in non-diabetic hypertensive patients: an analysis of the ESPECIAL trial.

BACKGROUND: Although adiponectin levels have been reported to be correlated with albuminuria, this issue remains unresolved in non-diabetic hypertensive subjects, particularly when urinary adiponectin is considered. METHODS: Urinary adiponectin levels were examined using an enzyme-linked immunosorbent assay in 229 participants. who used olmesartan as a hypertensive agent. Their albuminuria levels were measured for 16 weeks after randomization and initiation of conventional or intensive diet education. Linear or logistic regression models were applied, as appropriate, to explore the relationship with albuminuria itself or its response after the intervention. RESULTS: Urinary adiponectin levels were positively related to baseline albuminuria level (r = 0.529). After adjusting for several covariates, the adiponectin level was associated with the albuminuria level (ß = 0.446). Among the 159 subjects with baseline macroalbuminuria, the risk of consistent macroalbuminuria (> 300 mg/day) at 16 weeks was higher in the 3(rd) tertile of adiponectin than in the 1(st) tertile (odds ratio = 6.9), despite diet education. In contrast, among all subjects, the frequency of the normoalbuminuria achievement (< 30 mg/day) at 16 weeks was higher in the 1(st) tertile than in the 3(rd) tertile (odds ratio = 13.0). CONCLUSIONS: Urinary adiponectin may be a useful biomarker for albuminuria or its response after treatment in non-diabetic hypertensive patients.

Outcomes of predialysis nephrology care in elderly patients beginning to undergo dialysis.

BACKGROUND: The proportion of elderly patients beginning to undergo dialysis is increasing globally. Whether early referral (ER) of elderly patients is associated with favorable outcomes remains under debate. We investigated the influence of referral timing on the mortality of elderly patients. METHODS: We retrospectively assessed mortality in 820 patients aged ≥70 years with end-stage renal disease (ESRD) who initiated hemodialysis at a tertiary university hospital between 2000 and 2010. Mortality data was obtained from the time of dialysis initiation until December 2010. We assigned patients to one of two groups according to the time of their first encounters with nephrologists: ER (≥ 3 months) and late referral (LR; < 3 months). RESULTS: During a mean follow-up period of 25.1 months, the ER group showed a 24% reduced risk of long-term mortality relative to the LR group (HR = 0.760, P = 0.009). Rate of reduction in 90-day mortality for ER patients was 58% (HR = 0.422, P=0.012). However, the statistical significance of the difference in mortality rates between ER and LR group was not observed across age groups after 90 days. Old age, LR, central venous catheter, high white blood cell count and corrected Ca level, and lower levels of albumin, creatinine, hemoglobin, and sodium were significantly associated with increased risk of mortality. CONCLUSIONS: Timely referral was also associated with reduced mortality in elderly ESRD patients who initiated hemodialysis. In particular, the initial 90-day mortality reduction in ER patients contributed to mortality differences during the follow-up period.

The Decrement of Hemoglobin Concentration with Angiotensin II Receptor Blocker Treatment Is Correlated with the Reduction of Albuminuria in Non-Diabetic Hypertensive Patients: Post-Hoc Analysis of ESPECIAL Trial.

Blockade of the renin-angiotensin-aldosterone system exhibits a renoprotective effect; however, blockade of this system may also decrease hemoglobin (Hb) and erythropoietin (EPO) levels. We evaluated the correlation between reduced albuminuria and decreased hemoglobin concentrations after treatment with an angiotensin II receptor blocker (ARB). Two hundred forty-five non-diabetic hypertensive participants with established albuminuria and relatively preserved renal function were treated with an ARB (40 mg/day olmesartan) for eight weeks. Subsequent changes in various clinical parameters, including Hb, EPO, and albuminuria, were analyzed following treatment. After the 8-week treatment with an ARB, Hb and EPO levels significantly decreased. Patients with a greater decrease in Hb exhibited a greater reduction in 24-hour urinary albumin excretion compared with patients with less of a decrease or no decrease in Hb, whereas no associations with a decline in renal function and EPO levels were noted. Multivariate logistic regression analysis demonstrated a correlation between the reduction of urine albumin excretion and the decrease in Hb levels (after natural logarithm transformation, adjusted odds ratio 1.76, 95% confidence interval 1.21-2.56, P = 0.003). Linear regression analysis also supported this positive correlation (Pearson correlation analysis; R = 0.24, P < 0.001). Decreased Hb concentrations following ARB treatment were positively correlated with reduced albuminuria in non-diabetic hypertensive patients, regardless of decreased blood pressure and EPO levels or renal function decline.

A low-salt diet increases the estimated net endogenous acid production in nondiabetic chronic kidney disease patients treated with angiotensin receptor blockade.

BACKGROUND/AIMS: An acid-base imbalance precedes renal disease progression in patients with chronic kidney disease (CKD). Little is known about the effects of a low-salt diet (LSD) on net endogenous acid production (NEAP) levels in CKD patients using angiotensin receptor blockade. METHODS: We enrolled a total of 202 nondiabetic CKD patients who underwent an 8-week treatment with olmesartan from the original trial [Effects of Low Sodium Intake on the Antiproteinuric Efficacy of Olmesartan in Hypertensive Patients with Albuminuria (ESPECIAL) trial: NCT01552954]. The patients were divided into good- and poor-LSD-compliance groups. RESULTS: During the interventional 8 weeks, the NEAP in the good-compliance group increased compared to the control group (12.9 ± 32.0 vs. -2.0 ± 35.0 mmol/day, p = 0.002). NEAP was positively associated with the good-LSD-compliance group in the fully adjusted analyses (r = 0.135, p = 0.016). The additional reduction of 2.39 g/day of protein intake with a reduction of 1 g/day of salt intake did not increase the NEAP under angiotensin II receptor blockade (ARB) treatment with an LSD (r = 0.546, p < 0.001). CONCLUSION: We found that an LSD may increase the NEAP in nondiabetic CKD patients using ARB, which suggests that additional acid producing-protein restriction should be required to prevent the NEAP from rising.

A higher salt intake leads to a lower rate of adequate blood pressure control.

The relationship between salt intake and adequate blood pressure control is not well investigated in Korea populations, especially in patients with cardiovascular disease. This cross-sectional study enrolled 19,083 subjects who participated in the Korea National Health and Nutrition Examination Survey conducted from 2009-2011. The amount of salt intake was estimated using the Tanaka equations based on spot urine samples. Comparing patients with and without cardiovascular disease, systolic blood pressure (129.1±18.1 mmHg vs. 120.0±18.1 mmHg, P<0.001) and the amount of urinary sodium excretion (149.4±37.5 mM/day vs. 144.1±36.2 mM/day, P<0.001) were higher in patients with cardiovascular diseases. Among patients with cardiovascular disease, the high blood pressure group showed an increased amount of urinary sodium excretion compared to the normal blood pressure group (155.5±38.2 vs. 146.6±36.9 mM/day, P<0.001). The odds ratio (OR) of high blood pressure was higher (OR, 1.825; 95% CI, 1.187-2.807; P-for-trend 0.003, highest quartile of urinary sodium excretion vs. lowest quartile) in patients with cardiovascular disease. A higher amount of urinary sodium excretion was associated with a lower rate of adequate blood pressure control in Korean population, especially with cardiovascular disease.

Estimated 24-hour urine sodium excretion is correlated with blood pressure in Korean population: 2009-2011 Korean National Health and Nutritional Examination Survey.

No large-scale studies have investigated the association between salt intake and hypertension in Korean population. To investigate the relationship of blood pressure to salt consumption, we analyzed data from 19,476 participants in the 2009-2011 Korean National Health and Nutritional Examination Survey (KNHANES). Urinary sodium excretion over 24-hr (24HUNa) was estimated from spot urine tests using Tanaka's equation. The study subjects were stratified into hypertensive and normotensive groups. Hypertensive participants (n=6,552, 33.6%) had higher estimated 24HUNa, 150.4±38.8 mEq/day, than normotensive participants, 140.5±34.6 mEq/day (P<0.001). The association between 24HUNa and blood pressure outcomes was not affected by adjustment for other risk factors for hypertension (odds ratio 0.001; 95% confidence interval 0.001-0.003; P<0.001). Increases in 24HUNa of 100 mEq/day were associated with a 6.1±0.3/2.9±0.2 mmHg increase in systolic/diastolic blood pressure in all participants. This effect was stronger in hypertensive participants (increase of 8.1±0.5/3.4±0.3 mmHg per 100 mEq/day) and smaller in normotensive participants (2.9±0.3/1.3±0.2 mmHg). These results support recommendations for low salt intake in Korean population to prevent and control adverse blood pressure levels.

Analysis of correlation between 24-hour urinary sodium and the degree of blood pressure control in patients with chronic kidney disease and non-chronic kidney disease.

We investigated the association between 24-hr urinary sodium (24UNA) and adequacy of blood pressure (BP) control in patients with chronic kidney disease (CKD) and nonCKD. All data were collected retrospectively by accessing the electrical medical records in patients with 24-hr urine collection and serum creatinine. Enrolled 400 subjects were subgrouped by the amount of 24UNA, or CKD stage. The appropriate BP was defined as BP < 130/80 mmHg for subjects with proteinuria, and BP < 140/90 mmHg for subjects without proteinuria. The mean level of 24UNA was 166±76 mEq/day. The 24UNA group was an independently related factor to diastolic BP as a continuous variable. The rate of appropriate BP control in patients with proteinuria was highest in 24UNA <100 mEq/L (P=0.012). The odds to fail achievement of BP target in subjects with 24UNA≥90 mEq/day was 2.441 (1.249-4.772, P=0.009) higher than that of 24UNA <90 mEq/day among participants with proteinuria. There was difference in the amount of 24UNA between CKD and non-CKD except each stage of CKD group. In conclusion, salt intake estimated by 24-hr urine sodium excretion is a risk factor to achieve appropriate BP control.

Urinary sodium excretion has positive correlation with activation of urinary renin angiotensin system and reactive oxygen species in hypertensive chronic kidney disease.

It is not well described the pathophysiology of renal injuries caused by a high salt intake in humans. The authors analyzed the relationship between the 24-hr urine sodium-to-creatinine ratio (24HUna/cr) and renal injury parameters such as urine angiotensinogen (uAGT/cr), monocyte chemoattractant peptide-1 (uMCP1/cr), and malondialdehyde-to-creatinine ratio (uMDA/cr) by using the data derived from 226 hypertensive chronic kidney disease patients. At baseline, the 24HUna/cr group or levels had a positive correlation with uAGT/cr and uMDA/cr adjusted for related factors (P<0.001 for each analysis). When we estimated uAGT/cr in the 24HUna/cr groups by ANCOVA, the uAGT/cr in patients with ≥200 mEq/g cr was higher than in patients with <100 mEq/g cr (708 [95% CI, 448-967] vs. 334 [95% CI, 184-483] pg/mg cr, P=0.014). Similarly, uMDA/cr was estimated as 0.17 (95% CI, 0.14-0.21) pM/mg cr in patients with <100 mEq/g cr and 0.27 (95% CI, 0.20-0.33) pM/mg cr in patients with ≥200 mEq/g cr (P=0.016). During the 16-week follow-up period, an increase in urinary sodium excretion predicted an increase in urinary angiotensinogen excretion. In conclusion, high salt intake increases renal renin-angiotensin-system (RAS) activation, primarily, and directly or indirectly affects the production of reactive oxygen species through renal RAS activation.

Estimated amount of 24-hour urine sodium excretion is positively correlated with stomach and breast cancer prevalence in Korea.

Stomach cancer is one of the most common cancers in Korea. The aim of this study was to identify the association between the prevalence of cancer, particularly stomach cancer, and the amount of 24-hr urine sodium excretion estimated from spot urine specimens. The study included 19,083 subjects who took part in the Korean National Health and Nutritional Examination Survey between 2009 and 2011. The total amount of urine sodium excreted in a 24-hr period was estimated by using two equations based on the values for spot urine sodium and creatinine. In subjects who had an estimated 24-hr urine sodium excretion of more than two standard deviations above the mean (group 2), the prevalence of stomach cancer was higher than in subjects with lower 24-hr sodium excretion (group 1). By using the Tanaka equation to estimate it, the prevalence of stomach cancer was 0.6% (114/18,331) in group 1, whereas it was 1.6% (9/568) in group 2 (P=0.006). By using the Korean equation, the prevalence was 0.6% (115/18,392) in group 1, and 1.6% in group 2 (8/507) (P=0.010). By using the Tanaka equation, breast cancer in women is more prevalent in group 2 (1.9%, 6/324) than group 1 (0.8%, 78/9,985, P=0.039). Higher salt intake, as defined by the estimated amount of 24-hr urine sodium excretion, is positively correlated with a higher prevalence of stomach or breast cancer in the Korean population.