24-hour Urinary Potassium Excretion Research Articles

Net Endogenous Acid Excretion and Kidney Allograft Outcomes.

High dietary acid load may accelerate a decline in kidney function. We prospectively investigated whether dietary acid load is associated with graft outcomes in kidney transplant recipients, and whether venous bicarbonate mediates this association. We used data from 642 kidney transplant recipients with a functioning graft ≥1 year after transplantation. Net endogenous acid production was estimated using food frequency questionnaires and, alternatively, 24-hour urinary urea and potassium excretion to estimate net endogenous acid production. We defined the composite kidney end point as a doubling of plasma creatinine or graft failure. Multivariable Cox regression analyses, adjusted for potential confounders, were used to study the associations of dietary acid load with the kidney end point. We evaluated potential mediation effects of venous bicarbonate, urinary bicarbonate excretion, urinary ammonium excretion, titratable acid excretion, and net acid excretion on the association between net endogenous acid production and the kidney end point. The median net endogenous acid production using food frequency questionnaires and net endogenous acid production using urinary excretion were 40 (interquartile range, 35-45) and 54 (interquartile range, 44-66) mEq/day, respectively. During a median follow-up of 5.3 years (interquartile range, 4.1-6.0), 121 (19%) participants reached the kidney end point. After multivariable adjustment, net endogenous acid production using food frequency questionnaires and net endogenous acid production using urinary excretion (per SD higher) were independently associated with higher risk for kidney end point (hazard ratio, 1.33; 95% confidence interval, 1.12 to 1.57, P=0.001 and hazard ratio, 1.44; 95% confidence interval, 1.24 to 1.69, P<0.001, respectively). Baseline venous bicarbonate mediated 20% of the association between net endogenous acid production using food frequency questionnaires and the kidney end point. Baseline venous bicarbonate, urinary ammonium excretion, and net acid excretion mediated 25%, -14%, and -18%, respectively, of the association between net endogenous acid production using urinary excretion and the kidney end point. Higher dietary acid load was associated with a higher risk of doubling of plasma creatinine or graft failure, and this association was partly mediated by venous bicarbonate, urinary ammonium, and net acid excretion.

DIFFERENCES IN HYPERTENSION PHENOTYPES BETWEEN AFRICANS AND EUROPEANS: ROLES OF INHERITANCE AND ENVIRONMENT

Objective: Hypertension phenotypes differ in Africans and white Europeans, with a greater prevalence of low renin salt-sensitive hypertension and greater predisposition to adverse cardiac remodelling in Africans. We aim to elucidate roles of inheritance and environment in determining hypertension phenotypes in Africans born and resident in Nigeria (AA), sub-Saharan Africans living in the UK (AE) and white Europeans in the UK (EE). Design and method: 469 hypertensive subjects in the UK and Nigeria were enrolled. Biochemistry, blood pressure, left ventricular structure (echocardiography) and 24 h urinary collections of sodium and potassium were measured Results: 24-hour urinary sodium and potassium excretion were similar in AE and EE but lower in AA with a proportionately greater excretion of potassium compared to sodium in Africans resident in Europe compared to those in Africa (sodium excretion 46.9% greater in AE compared to AA and potassium excretion 109.8% greater in AE compared to AA, both P &lt; 0.01) so that the ratio of sodium to potassium in the urine was higher in AA compared to both AE and EE. Plasma renin was lower in Africans irrespective of residency compared to white Europeans, but aldosterone was higher in Africans in Europe compared to those in Africa (466.15 ± 32.95 pmol/L vs 258.60 ± 17.42 pmol/L, P &lt; 0.001). Left ventricular mass index adjusted for blood pressure was greatest in Africans in Europe (103.27 ± 2.32 g/m2) compared to those in Africa (89.28 ± 1.98 g/m2, P &lt; 0.01) or white Europeans (86.77 ± 2.63 g/m2, P &lt; 0.01). The difference between AE and AA was largely driven by a greater LV cavity size in AE compared to AA (difference in end diastolic diameter, 0.45 ± 0.056 cm, P &lt; 0.001). Consequently, the RWT showed a trend to “eccentricity” moving from AA to AE. Conclusions: Both genetic and environmental differences contribute to phenotypic differences between Africans in Europe and white Europeans. A low renin state is predominantly genetically determined whereas higher aldosterone, related to higher potassium intake or another environmental factor, may contribute to greater LV mass in Africans in Europe.

Spot Urine Samples to Estimate Na and K Intake in Patients With Chronic Kidney Disease and Healthy Adults: A Secondary Analysis From a Controlled Feeding Study

The objective of this study was to assess the agreement between estimated 24-hour urinary sodium excretion (e24hUNa) and estimated 24-hour urinary potassium excretion (e24hUK), calculated from a spot urine sample using several available equations and actual sodium and potassium intake from a controlled diet in both healthy participants and those with chronic kidney disease (CKD). This study is a secondary analysis of a controlled feeding study in CKD patients matched to healthy controls. Participants (n=16) consumed the controlled diet, which provided ∼2400mg Na/day and ∼3000mgK/day, for 8days. On days 7 and 8, participants consumed all meals and collected all urine in an inpatient research setting, and they were discharged on day 9. The day 7 morning spot urine sample was used to calculate e24hUNa and e24hUK, which was compared with known sodium and potassium intake, respectively. Average e24hUNa from the INTERSALT and Tanaka-Na equations were higher than actual sodium intake by 373mg and 559mg, respectively, though the differences were not significant. e24hUNa from the Nerbass-SALTED equation in CKD participants was significantly higher than actual sodium intake by ∼2000mg (P<.001), though e24hUNa from the Nerbass-RRID equation was not different from intake. e24hUK from the Tanaka-K equation was significantly lower than actual potassium intake (P<.001). For both e24hUNa and e24hUK for all participants, agreement with actual intake was poor, and e24hUNa and e24hUK were not correlated with actual sodium or potassium intake, respectively. e24hUNa and e24hUK are poor indicators of true sodium and potassium intake, respectively, in both healthy and CKD participants. Findings should be confirmed in larger sample sizes with varying levels of dietary sodium and potassium.

Urinary Sodium and Potassium, and Risk of Ischemic and Hemorrhagic Stroke (INTERSTROKE): A Case-Control Study.

BACKGROUNDAlthough low sodium intake (<2 g/day) and high potassium intake (>3.5 g/day) are proposed as public health interventions to reduce stroke risk, there is uncertainty about the benefit and feasibility of this combined recommendation on prevention of stroke.METHODSWe obtained random urine samples from 9,275 cases of acute first stroke and 9,726 matched controls from 27 countries and estimated the 24-hour sodium and potassium excretion, a surrogate for intake, using the Tanaka formula. Using multivariable conditional logistic regression, we determined the associations of estimated 24-hour urinary sodium and potassium excretion with stroke and its subtypes.RESULTSCompared with an estimated urinary sodium excretion of 2.8–3.5 g/day (reference), higher (>4.26 g/day) (odds ratio [OR] 1.81; 95% confidence interval [CI], 1.65–2.00) and lower (<2.8 g/day) sodium excretion (OR 1.39; 95% CI, 1.26–1.53) were significantly associated with increased risk of stroke. The stroke risk associated with the highest quartile of sodium intake (sodium excretion >4.26 g/day) was significantly greater (P < 0.001) for intracerebral hemorrhage (ICH) (OR 2.38; 95% CI, 1.93–2.92) than for ischemic stroke (OR 1.67; 95% CI, 1.50–1.87). Urinary potassium was inversely and linearly associated with risk of stroke, and stronger for ischemic stroke than ICH (P = 0.026). In an analysis of combined sodium and potassium excretion, the combination of high potassium intake (>1.58 g/day) and moderate sodium intake (2.8–3.5 g/day) was associated with the lowest risk of stroke.CONCLUSIONSThe association of sodium intake and stroke is J-shaped, with high sodium intake a stronger risk factor for ICH than ischemic stroke. Our data suggest that moderate sodium intake—rather than low sodium intake—combined with high potassium intake may be associated with the lowest risk of stroke and expected to be a more feasible combined dietary target.

586-P: Characteristics of 24-Hour Urinary Electrolyte Excretion and Its Correlation with Renal Function in Type 2 Diabetics

Objective: There are few studies on the characteristics of 24-hour urinary electrolyte excretion in patients with type 2 diabetes mellitus (T2DM),and it is unclear whether the level of 24-hour urinary electrolyte excretion is related to poor renal prognosis.This study aimed to explore associations between 24-hour urinary electrolyte excretion and renal function in T2DM patients. Methods: A total of 479 patients with T2DM in our hospital from 2018 to 2019 were enrolled. According to the estimated glomerular filtration rate (eGFR), patients were divided into normal group(eGFR≥90 mL/min/1.73m`2,n=317)and abnormal group(eGFR&amp;lt;90 mL/min/1.73m`2,n=162). The correlation between 24-hour urinary electrolyte excretion and eGFR in T2DM patients was analyzed. In addition, the 24-hour urine electrolyte excretion was compared with gender, diabetic duration, and HbA1c. Results: The levels of 24-hour urinary potassium, sodium and chlorine excretion in abnormal group were higher than normal group, the levels of calcium and phosphorus excretion were lower. Therein, levels of sodium(P=0.037) and calcium (P&amp;lt;0.001) had significant difference. The levels of 24-hour urinary potassium, sodium, chloride, calcium and phosphorus excretion in the male group were higher than female group, among which potassium (P&amp;lt;0.001), sodium (P=0.001), chloride (P=0.002), and phosphorus (P&amp;lt;0.001) were statistically significant. In addition, duration of disease and HbAlc was not related to 24-hour Urinary Electrolyte Excretion. Conclusion:There is a certain correlation between 24-hour urinary electrolyte excretion in T2DM and renal function. With the increase of 24-hour urinary sodium excretion and decrease of urinary calcium excretion, eGFR decreased, which was related to gender. Therefore, in patients with T2DM of the same gender, 24-hour urinary sodium and calcium excretion may be useful metabolic parameters for predicting poor renal prognosis, which needs further study. Disclosure Y. Wang: None. N. Li: None. L. Bu: None. H. Sun: None. B. Zhu: None. H. Li: None. S. Qu: None. Funding National Key Research and Development Program of China (2018YFC1314100); National Natural Science Foundation of China (81970677)

Estimates of Sodium and Potassium intake and their molar ratio in Irish children: Preliminary findings from NCFSII

AbstractThe Food Safety Authority of Ireland (FSAI) have set target maximum daily salt intakes for children (4–6y: 3 g, 7–10y: 5 g, 11–14y: 6g) while the European Food Safety Authority (EFSA) have set Adequate Intakes (AI) for potassium of 1100mg/d, 1800mg/d and 2700mg/d for children of the same respective age groups. An individual's sodium to potassium (Na:K) intake ratio is an important predictor of hypertension and the World Health Organization (WHO) recommend a Na:K intake ratio of ≤ 1.0mmol/mmol for both adults and children. Although the morbidities associated with hypertension may not be seen until adulthood, blood pressure in childhood has a significant association with blood pressure in adulthood. Therefore, estimation of Na:K intake ratios (best measured by urinary excretion) in children may predict their susceptibility to hypertension related diseases in later life. The aim of this study was to estimate sodium and potassium intake and mean molar Na:K intake ratio of Irish children and to assess compliance with dietary guidance.Morning spot urine samples were collected for 572 children aged 5–12 years (95% of total sample) as part of the nationally representative Irish National Children's Food Survey II (2017–2018) (NCFSII; www.iuna.net). Samples were transported, processed and stored using best practice procedures. Urinary excretion of sodium and potassium were measured using a Randox RX Daytona and were corrected for gender and age-specific 24-hour urine volume estimations based on 24-hour urine volume estimates from Australian children. SPSS Version 25 was used for all analyses.Mean 24-hour urinary sodium excretion was 2018mg/d, equivalent to an average salt excretion of 5.0g/d exceeding the FSAI maximum target intake for all age groups except 11–12 year olds. Mean 24-hour urinary potassium excretion was 1411mg/d with mean intakes below the AI from EFSA for all age groups with the exception of 5–6 year olds. The mean molar Na:K ratio of Irish children was 2.8 for boys and 3.4 for girls. Only 5% of Irish children met the WHO recommendation for a Na:K ratio of ≤ 1.0mmol/mmol.High intakes of sodium and low intakes of potassium reported in this study result in a low compliance with the WHO recommendation of a Na:K ratio ≤ 1.0mmol/mmol. This may lead to a higher risk of hypertension and related morbidities in later life. Based on these findings, dietary interventions to combat hypertension related diseases (such as lowering sodium and increasing potassium intakes) should be implemented from childhood.

Handgrip Strength and Its Association With Hydration Status and Urinary Sodium-to-Potassium Ratio in Older Adults

Objective: Older adults present higher risk of functional disability detected by handgrip strength and an increased risk of poor health conditions, such as dehydration and low values of the sodium-to-potassium (Na/K) ratio. This study aimed to quantify the association of hydration status and Na/K ratio with handgrip strength, based on the urinary excretion of older adults.Methods: A cross-sectional study was conducted in 735 older adults ≥ 65 years old. Handgrip strength was measured with a Jamar Dynamometer and low values were defined according to body mass index and to sex-specific cutoff points. The hydration status was evaluated based on free water reserve. Sodium and potassium intake were evaluated after converting 24-hour urinary sodium and potassium excretion, respectively. A logistic regression model was used to estimate the probability of presenting low handgrip strength, according to risk of hypohydration and to quartiles of Na/K, stratified by sex and adjusted for potential confounders.Results: The adjusted odds ratio (OR) for presenting low handgrip strength was higher in women at risk of hypohydration, but this association was not found in men. Both women and men with the highest values of Na/K ratio presented higher adjusted OR for low handgrip strength (OR in women was 2.03; 95% confidence interval [CI]: 1.12–3.68, and in men was 2.19; 95% CI: 1.11–4.29).Conclusions: The risk of hypohydration was directly associated with low handgrip strength in older women. In older adults, higher values of urinary Na/K ratio were also directly associated with low handgrip strength.

EFFICACY OF THE ANGIOTENSIN RECEPTOR BLOCKER LOSARTAN DURING HIGH POTASSIUM INTAKE IN CKD PATIENTS

Objective: High potassium intake increases natriuresis and lowers blood pressure (BP). Whether these beneficial effects are also present in chronic kidney disease (CKD) patients and whether potassium intake affects BP and proteinuria-lowering efficacy of angiotensin receptor blockade (ARB) is unknown. We set out to address the effect of potassium intake on BP and proteinuria response to losartan in non-diabetic proteinuric CKD patients. Design and method: We performed a post-hoc analysis of a placebo-controlled interventional cross-over study in which 33 non-diabetic proteinuric patients (mean baseline proteinuria 3.8 g/d) were treated for 6 weeks with placebo, losartan 100 mg, and losartan/hydrochlorothiazide 100 mg/25 mg, respectively. Patients underwent the 3 interventions during both a high (>200 mmol/d) and low-sodium diet (<100 mmol/d), in randomized order. To analyze the effects potassium intake, we categorized patients based on median split of 24-hour urinary potassium excretion, reflecting potassium intake. Treatment responses relative to placebo during high sodium were assessed. We used repeated measurements ANOVA with potassium intake as between subjects factor. Results: Mean potassium intake was stable during all 6 treatment periods. Patients with high potassium intake (>85 mmol/day) had similar BP reductions across all treatments as compared to low potassium intake (<85 mmol/day), whereas a trend of lower proteinuria reduction (p = 0.052) was observed for all treatments. Proteinuria reduction to losartan monotherapy was significantly lower during high potassium intake (20% vs. 40%, p = 0.02). The differences in antiproteinuric response abolished when adding a low sodium diet, hydrochlorothiazide, or both to losartan. Serum potassium was similar in both potassium intake groups throughout the study. Conclusions: In proteinuric CKD patients, the proteinuria, but not BP-lowering response to losartan was hampered during high potassium intake. Differences disappeared after sodium status change by low sodium diet and/or hydrochlorothiazide, suggesting that ARB inhibits natriuresis during high potassium intake, via a yet unknown mechanism.

Estimation of 24-hour urinary sodium, potassium, and creatinine excretion in patients with hypertension: can spot urine measurements replace 24-hour urine collection?

Owing to inconvenience of a 24‑hour urine collection, diagnostic methods based on spot urine samples are becoming increasingly popular. Spot urine sodium measurements could replace 24‑hour urinary sodium (24hUNa) excretion, considered a surrogate measure of dietary sodium intake. Spot urine-based approaches to estimating 24hUNa and 24‑hour urinary potassium (24hUK) excretion are potentially useful in patients with hypertension, for example, to identify increased urinary potassium excretion in individuals with primary aldosteronism and high dietary sodium intake in those with resistant hypertension. In this review, we summarized our research on spot urine-based estimation of 24hUNa, 24hUK, and 24‑hour urinary creatinine (24hUCr) excretion to avoid the need for a 24‑hour urine collection in patients with hypertension. We found that the Pan American Health Organization (PAHO) formula was generally the best for predicting the average 24hUNa and 24hUK excretion in hospitalized patients with hypertension, while the Kawasaki equation was inferior for estimating 24hUNa and the Tanaka equation was inferior for estimating 24hUK excretion. However, all 3 equations were imprecise in terms of estimating individual 24hUNa or 24hUK excretion. We also confirmed the general utility of the equations for estimating 24hUCr excretion in hypertensive individuals but with significant differences between various equations, the best formulas being Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) and Rule. Compared with the combined PAHO/CKD‑EPI formula, the Tanaka and Kawasaki equations underestimated increased 24hUNa and 24hUK excretion. Thus, the combined PAHO/CKD‑EPI formula might be the best for identifying increased 24hUNa and 24hUK excretion in patients with hypertension.

Salt Preference is Linked to Hypertension and not to Aging.

BackgroundSeasoning is one of the recommended strategies to reduce salt in foods. However, only a few studies have studied salt preference changes using seasoning.ObjectivesThe aim of this study was to compare preference for salty bread, and if seasoning can change preference in hypertensive and normotensive, young and older outpatients.MethodsOutpatients (n = 118) were classified in four groups: older hypertensive subjects (OH) (n = 32), young hypertensive (YH) (n = 25); older normotensive individuals (ON) (n = 28), and young normotensive (YN) (n = 33). First, volunteers random tasted bread samples with three different salt concentrations. After two weeks, they tasted the same types of breads, with seasoning added in all. Blood pressure (BP), 24-hour urinary sodium and potassium excretion (UNaV, UKV) were measured twice. Analysis: Fisher exact test, McNamer’s test and ANCOVA. Statistical significance: p < 0.05.ResultsSystolic BP, UNaV, and UKV were greater in HO and HY and they had a higher preference for saltier samples than normotensive groups (HO: 71.9%, HY: 56% vs. NO: 25%, NY; 6%, p<0.01). With oregano, hypertensive individuals preferred smaller concentrations of salt, with reduced choice for saltier samples (HO: 71.9% to 21.9%, and HY: 56% to 16%, p = 0.02), NO preferred the lowest salt concentration sample (53.6% vs. 14.3%, p < 0.01), and NY further increased the preference for the lowest one (63.6% vs. 39.4%, p = 0.03).ConclusionsOlder and younger hypertensive individuals prefer and consume more salt than normotensive ones, and the seasoned bread induced all groups to choose food with less salt. Salt preference is linked to hypertension and not to aging in outpatients.

Daily urinary sodium and potassium excretion in Chinese first-generation migrants in Italy

BackgroundChina has one of the highest salt intake levels in the world, and Chinese people form one of the largest foreign-born communities now living in Europe. The present study was performed to assess 24-hour urinary sodium and potassium excretion in Chinese migrants in Italy and to explore possible associations with hypertension, hypertension awareness, and length of residence in Italy. MethodsA cross-sectional evaluation was conducted on 319 first-generation Chinese migrants (154 women and 165 men) aged 18–70 years. Subjects were asked to do a 24-hour urine collection and the relationships of urinary sodium and potassium and arterial blood pressure, hypertension (BP ≥ 140/90 mmHg or anti-hypertensive drug use), hypertension awareness, and years of residence in Italy were investigated with linear or logistic regression analysis. ResultsSodium excretion was 145.2 mmol/day (95%CI 138.0–152.3) in men, and 134.7 (95%CI 127.6–141.8) in women corresponding to a dietary salt intake of 9.4 g/day (95%CI 9.0–9.9) and 8.8 (95%CI 8.3–9.2) respectively. Potassium excretion was 35.1 mmol/day (95%CI 33.6–36.5), with no significant difference by gender. At multivariable adjusted linear regression analysis body mass index, low education level, and hypertension were positive predictors of sodium urinary excretion; gender (women), and body mass index were positive predictors of potassium excretion. Sodium and potassium excretion were unaffected by hypertension awareness or years of residence in Italy. ConclusionsSodium excretion in Chinese workers is higher than recommended and in line with high salt intake in Italy. Potassium consumption remains low.

Blood Pressure in relation to 24-Hour Urinary Sodium and Potassium Excretion in a Uruguayan Population Sample.

Many public health policies in Latin America target an optimized sodium and potassium intake. The aims of this study were to assess the sodium and potassium intake using 24-hour urinary analysis and to study their association with blood pressure in a Uruguayan population cohort using cluster analysis. A total of 149 participants (aged 20–85 years) were included in the study, and office blood pressure, anthropometric measurements, biochemical parameters in the blood, and 24-hour urine samples were obtained. The overall mean sodium and potassium excretion was 152.9 ± 57.3 mmol/day (8.9 ± 3.4 g/day of salt) and 55.4 ± 19.6 mmol/day, respectively. The average office systolic/diastolic blood pressure was 124.6 ± 16.7/79.3 ± 9.9 mmHg. Three compact spherical clusters were defined in untreated participants based on predetermined attributes, including blood pressure, age, and sodium and potassium excretion. The major characteristics of the three clusters were (1) high systolic blood pressure and moderate sodium excretion, (2) moderate systolic blood pressure and very high sodium excretion, and (3) low systolic blood pressure and low sodium excretion. Participants in cluster three had systolic blood pressure values that were 23.9 mmHg (95% confidence interval: −29.5 to −1.84) lower than those in cluster one. Participants in cluster two had blood pressure levels similar to those in cluster one (P = 0.32) and worse metabolic profiles than those in cluster one and three (P < 0.05). None of the clusters showed high blood pressure levels and high sodium excretion. No linear association was found between blood pressure and urinary sodium excretion (r < 0.14; P > 0.47). An effect of sodium and potassium intake on blood pressure levels was not found at the population level using regression or cluster analysis.

Comparison of three formulas to estimate 24-hour urinary sodium and potassium excretion in patients hospitalized in a hypertension unit

Measurements of 24-hour urinary sodium (24hrUNa) and potassium (24hrUK) excretion are useful in hypertensives but 24-hour urine collection may be difficult or unreliable. We compared three formulas (Tanaka, Kawasaki, Pan American Health Organization [PAHO]) proposed to estimate 24hrUNa and 24hrUK based on spot urine measurements. We studied 382 patients admitted to a hypertension unit. Sodium, potassium, and creatinine levels were measured using standard laboratory methods in a morning urine sample, followed by 24-hour urinary collection. Agreement between estimated and measured 24hrUNa and 24hrUK was evaluated using the Pearson correlation and Bland-Altman plots. Measured 24hrUNa was 158 ± 75 mmol/d and 24hrUK was 54 ± 24 mmol/d. The correlation coefficient was r = 0.53 for estimated versus measured 24hrUNa, r = 0.69–0.73 for estimated versus measured 24hrUK (all P < .001). The mean bias for 24hrUNa was significantly smaller for Tanaka (10.5 mmol/d) and PAHO (11.5 mmol/d) compared with Kawasaki formula (−29.9 mmol/d). The mean bias for 24hrUK was significantly smaller for Kawasaki (7.3 mmol/d) and PAHO (8.3 mmol/d) compared with Tanaka formula (16.5 mmol/d). Using a single morning urine sample, we found the PAHO formula to be the best for predicting mean 24hrUK and 24hrUNa in hospitalized hypertensive patients. However, precision and accuracy of all the evaluated formulas was inadequate.

Abstract 008: Casual and 24-hour Urinary Sodium-to-potassium Ratio and Intakes of Sodium and Potassium Among Men and Women From Multi-ethnic General Populations: The Intersalt Study

Background: Urinary sodium-to-potassium ratio may be more strongly related to blood pressure and cardiovascular disease than either urinary sodium or potassium alone. The casual urine sodium-to-potassium ratio is readily obtained, can provide prompt on-site feedback, and with repeated measurements may provide useful individual estimates of 24-hour urinary sodium-to-potassium ratio. The World Health Organization (WHO) has recently published guidelines for sodium and potassium intakes, but no generally accepted guideline prevails for favorable sodium-to-potassium ratio. Objective: Our primary aim was to compare the level of urinary Na/K ratio with the current recommended levels of Na and K intakes suggested in WHO guidelines. Methods: INTERSALT is an international study on associations of multiple urinary variables, with blood pressure (BP), based on standardized data on 24-hour and casual urinary electrolyte excretion in 10,065 individuals from 52 population samples in 32 countries. The associations between casual urinary sodium-to-potassium ratio and 24-hour urinary sodium and potassium excretion of individuals were assessed by correlation and stratification analysis. Results: Mean 24-hour sodium and potassium excretions were 156.0 mmol/24h and 55.2 mmol/24h; mean 24-hour urinary sodium-to-potassium ratio was 3.24. Pearson-r correlation coefficients of casual urinary sodium-to-potassium ratio with 24-hour sodium and potassium excretions were 0.42 and -0.34, respectively, and these were 0.57 and -0.48 for 24-hour urinary sodium-to-potassium ratio. The proportion of participants with estimated sodium chloride intake below the WHO recommended guideline of 85 mmol/day was 61.1% for those with casual urinary sodium-to-potassium ratio less than 1, and 96.3% where the 24-hour ratio was less than 1. For potassium, the proportion of people with potassium intake more than the WHO recommended guideline of 90 mmol/day was 21.3% where the casual urinary sodium-to-potassium ratio was less than 1 and 28.6% for the 24-hour urinary sodium-to-potassium ratio. Conclusions: Casual urinary sodium-to-potassium ratio less than 1 may be a useful indicator of adherence to the World Health Organization recommended levels of sodium intake, and to a lesser extent potassium intake in diverse different populations.

Estimated 24-Hour Urinary Sodium and Potassium Excretion in US Adults

In 2010, the Institute of Medicine (now the National Academy of Medicine) recommended collecting 24-hour urine to estimate US sodium intake because previous studies indicated 90% of sodium consumed was excreted in urine. To estimate mean population sodium intake and describe urinary potassium excretion among US adults. In a nationally representative cross-sectional survey of the US noninstitutionalized population, 827 of 1103 (75%) randomly selected, nonpregnant participants aged 20 to 69 years in the examination component of the National Health and Nutrition Examination Survey (NHANES) collected at least one 24-hour urine specimen in 2014. The overall survey response rate for the 24-hour urine collection was approximately 50% (75% [24-hour urine component response rate] × 66% [examination component response rate]). 24-hour collection of urine. Mean 24-hour urinary sodium and potassium excretion. Weighted national estimates of demographic and health characteristics and mean electrolyte excretion accounting for the complex survey design, selection probabilities, and nonresponse. The study sample (n = 827) represented a population of whom 48.8% were men; 63.7% were non-Hispanic white, 15.8% Hispanic, 11.9% non-Hispanic black, and 5.6% non-Hispanic Asian; 43.5% had hypertension (according to 2017 hypertension guidelines); and 10.0% reported a diagnosis of diabetes. Overall mean 24-hour urinary sodium excretion was 3608 mg (95% CI, 3414-3803). The overall median was 3320 mg (interquartile range, 2308-4524). In secondary analyses by sex, mean sodium excretion was 4205 mg (95% CI, 3959-4452) in men (n = 421) and 3039 mg (95% CI, 2844-3234) in women (n = 406). By age group, mean sodium excretion was 3699 mg (95% CI, 3449-3949) in adults aged 20 to 44 years (n = 432) and 3507 mg (95% CI, 3266-3748) in adults aged 45 to 69 years (n = 395). Overall mean 24-hour urinary potassium excretion was 2155 mg (95% CI, 2030-2280); by sex, 2399 mg (95% CI, 2253-2545) in men and 1922 mg (95% CI, 1757-2086) in women; and by age, 1986 mg (95% CI, 1878-2094) in adults aged 20 to 44 years and 2343 mg (95% CI, 2151-2534) in adults aged 45 to 69 years. In cross-sectional data from a 2014 sample of US adults, estimated mean sodium intake was 3608 mg per day. The findings provide a benchmark for future studies.

Measurements of 24-Hour Urinary Sodium and Potassium Excretion

Measurements of 24-Hour Urinary Sodium and Potassium Excretion

Increased urinary sodium excretion is associated with systolic blood pressure in first degree relatives of hypertensive patients in Ibadan, Southwestern Nigeria.

IntroductionUnderstanding the risk factors of hypertension has led to a better understanding of the pathogenesis, prevention and reduction in morbidity of hypertension. It is well known that offsprings of hypertensive parents have an increased risk of developing hypertension. It is therefore necessary to explore the physiological differences between normotensive patients with and without a positive family history of hypertension with respect to their urinary excretion of sodium.MethodsThis study was carried out at the University College Hospital, Ibadan Nigeria, to determine if normotensive patients with a positive family history of hypertension are different with respect to their urinary excretion of electrolytes and blood pressure. It examined the relationship between 24-hour urinary excretion of sodium, chloride and potassium, urea and creatinine and blood pressure in subjects with and without family history of hypertension. It was a case-control study of sixty-two subjects: normotensive patients’ first degree relatives of primary hypertensive patients and normotensive patients without positive family history.ResultsThe mean (SD) systolic blood pressures for subjects with and without family history of hypertension were significantly different: 120.0(22.25) and 105.0(17.50) respectively, (p=0.001). The mean arterial blood pressures were significantly different: 86.4(10.2) mmHg and 80.1(8.1) mmHg respectively (p=0.010). The mean (SD) 24-hour urinary excretion of sodium for normotensive patients with and without positive family history of hypertension were 180.5 (45.50) mEq/L, and 156.0(36.25) mEq/L respectively. Systolic blood pressure and 24-hour urinary excretion of sodium was also higher in normotensive subjects with a positive family history of hypertension.ConclusionSystolic blood pressure and twenty-four hour urinary excretion of sodium were higher in normotensive subjects with a positive family history of hypertension than in those without a family history of hypertension.

Association Between Urinary Sodium and Potassium Excretion and Blood Pressure Among Adults in the United States: National Health and Nutrition Examination Survey, 2014.

Higher levels of sodium and lower levels of potassium intake are associated with higher blood pressure. However, the shape and magnitude of these associations can vary by study participant characteristics or intake assessment method. Twenty-four-hour urinary excretion of sodium and potassium are unaffected by recall errors and represent all sources of intake, and were collected for the first time in a nationally representative US survey. Our objective was to assess the associations of blood pressure and hypertension with 24-hour urinary excretion of sodium and potassium among US adults. Cross-sectional data were obtained from 766 participants age 20 to 69 years with complete blood pressure and 24-hour urine collections in the 2014 National Health and Nutrition Examination Survey, a nationally representative survey of the US noninstitutionalized population. Usual 24-hour urinary electrolyte excretion (sodium, potassium, and their ratio) was estimated from ≤2 collections on nonconsecutive days, adjusting for day-to-day variability in excretion. Outcomes included systolic and diastolic blood pressure from the average of 3 measures and hypertension status, based on average blood pressure ≥140/90 and antihypertensive medication use. After multivariable adjustment, each 1000-mg difference in usual 24-hour sodium excretion was directly associated with systolic (4.58 mm Hg; 95% confidence interval [CI], 2.64-6.51) and diastolic (2.25 mm Hg; 95% CI, 0.83-3.67) blood pressures. Each 1000-mg difference in potassium excretion was inversely associated with systolic blood pressure (-3.72 mm Hg; 95% CI, -6.01 to -1.42). Each 0.5 U difference in sodium-to-potassium ratio was directly associated with systolic blood pressure (1.72 mm Hg; 95% CI, 0.76-2.68). Hypertension was linearly associated with progressively higher sodium and lower potassium excretion; in comparison with the lowest quartile of excretion, the adjusted odds of hypertension for the highest quartile was 4.22 (95% CI, 1.36-13.15) for sodium, and 0.38 (95% CI, 0.17-0.87) for potassium (P<0.01 for trends). These cross-sectional results show a strong dose-response association between urinary sodium excretion and blood pressure, and an inverse association between urinary potassium excretion and blood pressure, in a nationally representative sample of US adults.

Diagnostic value of potassium level in a spot urine sample as an index of 24-hour urinary potassium excretion in unselected patients hospitalized in a hypertension unit.

BackgroundPrimary hyperaldosteronism may be associated with elevated 24-hour urinary potassium excretion. We evaluated the diagnostic value of spot urine (SU) potassium as an index of 24-hour urinary potassium excretion.MethodsWe measured SU and 24-hour urinary collection potassium and creatinine in 382 patients. Correlations between SU and 24-hour collections were assessed for potassium levels and potassium/creatinine ratios. We used the PAHO formula to estimate 24-hour urinary potassium excretion based on SU potassium level. The agreement between estimated and measured 24-hour urinary potassium excretion was evaluated using the Bland-Altman method. To evaluate diagnostic performance of SU potassium, we calculated areas under the curve (AUC) for SU potassium/creatinine ratio and 24-hour urinary potassium excretion estimated using the PAHO formula.ResultsStrongest correlation between SU and 24-hour collection was found for potassium/creatinine ratio (r = 0.69, P<0.001). The PAHO formula underestimated 24-hour urinary potassium excretion by mean 8.3±18 mmol/d (95% limits of agreement -28 to +44 mmol/d). Diagnostic performance of SU potassium/creatinine ratio was borderline good only if 24-hour urinary potassium excretion was largely elevated (AUC 0.802 for 120 mmol K+/24 h) but poor with lower values (AUC 0.696 for 100 mmol K+/24 h, 0.636 for 80 mmol K+/24 h, 0.675 for 40 mmol K+/24 h). Diagnostic performance of 24-hour urinary potassium excretion estimated by the PAHO formula was excellent with values above 120 mmol/d and good with lower values (AUC 0.941 for 120 mmol K+/24 h, 0.819 for 100 mmol K+/24 h, 0.823 for 80 mmol K+/24 h, 0.836 for 40 mmol K+/24 h).ConclusionsSpot urine potassium/creatinine ratio might be a marker of increased 24-hour urinary potassium excretion and a potentially useful screening test when reliable 24-hour urine collection is not available. The PAHO formula allowed estimation of the 24-hour urinary potassium excretion based on SU measurements with reasonable clinical accuracy.

Abstract MP039: Association Between Estimated 24-hour Urinary Sodium and Potassium Excretion and Blood Pressure in a Japanese Cohort: a Repeated Measure Analysis

Background: While measurement of sodium (Na) and potassium (K) from the collection of urine over a 24-hour period are associated with blood pressure, relationships with 24-hour urinary excretion estimates from more conveniently collected spot urine samples are less clear. Objectives: The purpose of this report is to examine the association of estimated 24-hour excretion of Na, K and their ratio from annually repeated spot urine samples with systolic (SBP) and diastolic (DBP) blood pressures. Methods: Data include 4,958 normotensive Japanese aged 19 to 55 years who participated in annual physical examinations over a 5-year period in the High-Risk and Population Strategy for Occupational Health Promotion Study (1999-2004). At each examination, spot urine samples were collected in the morning and blood pressure was measured following standardized procedures. 24-hour urinary excretion of Na and K were estimated from spot urine specimens using the formula of Tanaka. Adjustments were made for potential confounding from demographic, lifestyle education, body mass index, smoking, alcohol consumption and physical activity. Mixed-effects regression models were used to examine the association of the estimated 24-hour excretion of Na, K, and the sodium-to-potassium (Na:K) ratio with SBP and DBP over the 5-year period of study. Results: A one standard deviation (SD) increase in the estimated 24-hour excretion of Na (36.6 mmol/day) was associated with a 1.3 mm Hg higher SBP and a 0.8 mm Hg higher DBP (P&lt;.001). The association between Na and SBP was greater in men (1.4 mm Hg per SD) than in women (0.9 mm Hg per SD, P=.003 for interaction) and increased with age (1.0 mm Hg per SD at &lt;35 years of age, 1.2 mm Hg per SD at 35 to 45 years of age, and 1.8 mm Hg per SD at &gt;45 years of age, P&lt;.001 for interaction). Estimated 24-hour excretion of K was inversely associated with blood pressure where a one SD increase (8.9 mmol/day) was associated with a 1.1 mm Hg lower SBP and 0.7 mm Hg lower DBP (P&lt;.001). Unlike the estimated 24-hour excretion of Na, interactions between K and age or sex were absent. Estimated 24-hour Na:K ratio were positively associated with SBP and DBP, with greater effects in men than in women and increasing positive associations with age (P&lt;.01 for each interaction). Conclusions: Estimated 24-hour excretion of Na, K, and the Na:K ratio from spot urine samples have significant associations with blood pressure. Findings suggest that the less costly and more convenient collection of spot urine samples for estimating excretion of Na, K, and their ratio over a 24-hour period may be an efficient way of monitoring these electrolytes in large population-based samples.