Incomplete Urine Collection Research Articles

#2827 Beyond the scale: unveiling the kidney stone risk after bariatric surgery

Abstract Background and Aims Nephrolithiasis is a prevalent condition, with calcium oxalate being the primary component found in kidney stones. Both obesity and gastric bypass surgery pose as risk factors for nephrolithiasis. Malabsorptive bariatric procedures alter 24-hour urine profiles, leading to increased urinary oxalate and reduced urinary citrate levels. This study aims to evaluate the risk factors for calcium oxalate lithiasis in a population after gastric bypass surgery at our center. Method We performed a monocentric retrospective study to evaluate hyperoxaluria and urinary lithiasis in patients who underwent gastric bypass surgery between 2020 and 2021. We assessed urinary oxalate excretion, urinary citrate excretion, and urinary sodium excretion between 4 and 28 months after surgery. To confirm the adequacy of the collection, a comparison was made with the expected urinary creatinine value (20 to 25 mg/kg ideal weight for men and 15 to 20 mg/kg ideal weight for women). We developed a risk score: citraturia < 288 mg/24 h (1 point); oxaluria > 45 mg/L (1 point) and natriuresis > 97.75 mmol/24 h (1 point). Patients were classified as without risk (0 points), at low risk (1 point), at high risk (2 points), and at very high risk (3 points). Additionally, the patients’ historical incidence of lithiasis was examined, both preoperatively and postoperatively, using clinical records. Post-surgery assessments included imaging evidence of lithiasis (when available) or clinical episodes of renal colic. Results Fifty-six patients underwent a 24-hour urine collection. Twenty-two were excluded due to incomplete urine collection, determined by the expected urinary creatinine value and a time lapse exceeding 28 months between surgery and analytical assessment. The median time elapsed between surgery and analytical evaluation was 9.5 months [IQR 6.3 - 12] months. A total of 34 patients were included in the study, 8.8% were male and the median age of the patients was 51.5 [IQR 42.3–57.8] years. The median body mass index decreased from 43.1 [IQR 39.7–46.3] kg/m2 before to 31.8 [IQR 28.6–35.7] kg/m2 six months after surgery. The low risk for calcium oxalate lithiasis in the examined patient sample was 52.9% (n = 18); high risk 20.6% (n = 7), no risk 26.5% (n = 9) and very high risk 0%. We detected 3 (8.8%) patients with concentration hyperoxaluria, 20 (58.8%) patients with natriuresis > 97.75 mmol/24 h and 8 (23.5%) patients with reduced urinary citrate levels. All patients exhibited normal kidney function. The median follow-up duration was 27 months. Out of the total number of patients, only 3 reported renal colic episodes, and imaging evidence of lithiasis was found in just 2 of them before surgery. Among those with a risk score > 0, only 1 had a history of lithiasis. Throughout the follow-up period, none of the patients experienced new lithiasis post-surgery. Regarding the limitations of our study, we highlight the relatively brief duration of follow-up, which may pose challenges in comprehensively evaluating outcomes such as lithiasis. Additionally, the absence of imaging screening represents a notable constraint, impeding the comprehensive assessment of patients with asymptomatic lithiasis. Conclusion This study concludes that within the bariatric surgery population, a specific subgroup is at an elevated risk for renal lithiasis. Recognizing this subgroup promptly and instituting heightened preventive measures may prove advantageous within this demographic.

High protein intake and nitrogen balance in patients receiving venovenous extracorporeal membrane oxygenation: A descriptive cohort study.

This retrospective cohort study sought to describe the ability of high protein regimens to achieve nitrogen equilibrium in patients receiving venovenous extracorporeal membrane oxygenation (VV ECMO). Patients aged ≥18 years with a documented nitrogen balance study (NB) on VV ECMO between February 2018 and December 2021 were included. Studies with incomplete 24-h urine collections or changes in blood urea nitrogen ≥10 mg/dl were excluded. Data were summarized, correlation between first NB and potentially contributing variables was assessed with Kendall tau. Subanalysis described findings after stratifying for weight class (obese vs nonobese) and duration of VV ECMO at the time of NB. A total of 68 NBs in 30 patients were included; 47% of the cohort had obesity. The number of NBs per patient was 2.2 ± 1.1, which were completed on a median of 31.5 (interquartile range: 16, 53.8) days receiving ECMO. Nitrogen equilibrium or positive balance was achieved in 72% of studies despite elevated nitrogen excretion. Patients received 87.9 ± 16.8% of prescribed protein on NB days for average intakes of 2.4 ± 0.4 g/kg of actual weight per day and 2.4 ± 0.5 g/kg of ideal weight per day in patients without and with obesity. Median NB in patients without obesity was -1.46 (-8.96, 2.98) g/day and -0.21 (-10.58, 4.04) g/day in patients with obesity. A difference in median NB after stratification for timing was observed (P = 0.029). Nitrogen equilibrium can be achieved with high protein intake in adults receiving VV ECMO. NB monitoring is one tool to individualize protein prescriptions throughout the course of VV ECMO.

#4412 URINARY SODIUM-TO-POTASSIUM RATIO DOES NOT ACCURATELY REFLECT DIETARY SODIUM-TO-POTASSIUM RATIO

Abstract Background and Aims Low sodium intake is associated with a lower blood pressure and less proteinuria, which are important therapeutic targets in chronic kidney disease. In contrast, a low potassium intake has been associated with higher blood pressure and a higher incidence of chronic kidney disease and cardiovascular events. Counselling of patients regarding their sodium and potassium intake requires accurate estimation of their intake, but 24-hour urinary sodium and potassium excretion can deviate substantially from actual intake. Urinary sodium-to-potassium (Na/K) ratio is a promising alternative as it is less affected by incomplete urine collections and additionally captures both the effect of sodium and potassium. Our study aimed to assess whether the Na/K ratio in 24-hour urine reflects dietary intake more accurately than separate measurement of sodium or potassium in 24-hour urine. Method We performed a post-hoc analysis on data from the long-term sodium balance studies Mars105 and Mars520. Ten healthy participants consumed a diet with a known sodium and potassium content and collected 24-hour urine samples for 105 or 205 days. We calculated the log fold difference between dietary intake and urinary excretion of sodium, potassium and Na/K ratio. A mixed-effects model with a random intercept per subject was used to compare these estimates of accuracy. Subsequently, we performed a subgroup analysis per salt intake level (i.e. 6, 9 or 12 grams per day) and assessed the effect of increasing the number of 24-hour urine collections. Results Overall, the urinary Na/K ratio underestimated dietary Na/K ratio with a median difference of -0.21 (IQR -0.47 to 0.09). Estimation of dietary Na/K ratio intake using the urinary Na/K ratio was significantly less accurate compared to using urinary sodium or potassium measurement for estimation of sodium or potassium intake (Figure 1A). Only during a salt intake of 6 grams per day, the urinary Na/K ratio did not perform significantly worse than sodium measurements. Although increasing the number of 24-hour urine measurements to three or seven improved the accuracy of the urinary Na/K ratio, it remained inferior to separate assessment of urinary sodium and potassium excretion (Figure 1B). Conclusion The 24-hour urinary Na/K ratio is less accurate than 24-hour urinary sodium or potassium excretion for estimation of dietary intake in a controlled setting in healthy volunteers.

URINE SODIUM-TO-POTASSIUM RATIO DOES NOT ACCURATELY REFLECT DIETARY SODIUM-TO-POTASSIUM RATIO

Objective: High sodium intake is associated with an increased risk of cardiovascular disease, whereas a high potassium intake is associated with a reduced risk. Dietary counselling requires accurate estimation of sodium and potassium intake, but 24-hour urine sodium and potassium excretion demonstrated not to reflect actual intake. Urine sodium-to-potassium (Na/K) ratio is a promising alternative as it may be less affected by aldosterone-induced rhythmic changes in total body sodium and potassium content, is less influenced by incomplete urine collections, and incorporates both the effect of sodium and potassium. Our study assesses whether 24-hour urine Na/K ratio is superior in predicting dietary intake compared to 24-hour urine sodium or potassium excretion. Design and method: A post-hoc analysis was performed on data from the long-term sodium balance studies Mars105 and Mars520. Ten healthy participants received a diet with a known sodium and potassium content and collected 24-hour urine samples for 105 or 205 days. We calculated the log fold difference between dietary intake and urine content of sodium, potassium and Na/K ratio. We compared these estimates of accuracy using a mixed-effects model with a random intercept per subject. We analysed whether the accuracy differed among 6, 9 and 12 grams salt intake or was affected by the number of 24-hour urine collections. Results: Urine Na/K ratio underestimated dietary Na/K ratio with a median difference of -0.21 (IQR -0.47 to 0.09). Compared to sodium and potassium assessment, the Na/K ratio was significantly less accurate in predicting intake (Figure 1A). Only for the 6 gram salt phase the Na/K ratio did not perform significantly worse than sodium measurements. Increasing the number of 24-hour urine measurements to three or seven improved accuracy of the Na/K ratio, although it remained inferior to separate assessment of sodium and potassium excretion (Figure 1B). Conclusions: The 24-hour urine Na/K ratio is less accurate than 24-hour urine sodium excretion for estimation of dietary intake in a controlled setting.

PS-P14-2: ARTERIAL HYPERTENSION AND SALT CONSUMPTION IN LITHUANIA

Objective: Though it is an easily modifiable factor, high salt consumption remains the major contributor of the development of arterial hypertension and cardiovascular mortality. The World Health Organization recommends to consume less than 5 g salt per day. We aimed to evaluate the associations of 24-hour urinary sodium excretion and arterial blood pressure in Lithuanian adult population. Design and method: 1082 randomly selected individuals (18–69 years) were invited to participate in the study. We obtained 1035 samples of 24-hour urine collections, but 147 participants were excluded due to incomplete or inaccurate urine collection and/or 24 h urinary creatinine excretion outside 2 standard deviations of the sex-specific distribution. Three blood pressure (BP) readings were measured, separated by at least 1 min. Arterial hypertension was defined as systolic or diastolic BP > 140/90 mmHg and/or antihypertensive treatment and/or previously diagnosed hypertension. 9 individuals were excluded due to missing blood pressure measurements. Results: In a final analysis 879 individuals were enrolled, 52.67% was female. Mean age of all participants was 47.49 (±12.05) years old. Mean 24-hour urinary sodium excretion was 162.5mmol/24 hours and calculated mean salt consumption was 9.97 g (±5.29). Males had higher mean salt consumption than females (11.76 ± 5.8 g vs. 8.36 ± 4.2, p < 0.001). 35.7% of participants were identified to have arterial hypertension, a quarter were treated with antihypertensive medication. Hypertensive individuals had significantly higher salt consumption than normotensive participants of this study (11.1 ± 6.3 g vs. 9.35 ± 4.5 g, p < 0.01). Correlation coefficient between arterial hypertension and salt consumption was 0.25 (p < 0.001). Conclusions: Mean salt consumption in Lithuania twofold exceeds recommended amount. Male individuals use more salt than female. Hypertensive individuals have higher salt consumption.

ESTIMATION OF MEAN SALT INTAKE IN LITHUANIA BY 24-HOUR URINARY SODIUM EXCRETION

Objective: High salt intake is associated with increased arterial blood pressure, high risk of other preventable cardiovascular diseases, reduced life expectancy and higher mortality. WHO strongly recommends to take less than 5 g of salt per day. The aim of this study was to evaluate mean salt intake by 24-hour urinary sodium excretion and correlations with arterial blood pressure in Lithuanian population. Design and method: 1034 participants of age 18–69 years were invited to participate in the study and collect 24-hour urine using random sample design. Their blood pressure (BP) was measured 3 times. Arterial hypertension was defined as systolic or diastolic BP > 140/90 mmHg. 146 participants were excluded due to incomplete or inaccurate urine collection and 24 h urinary creatinine excretion outside 2 standard deviations of the sex-specific distribution. Results: 888 participants were included in a final analysis. An average age of participants was 47,4 years and 52,48% were women. Mean calculated salt intake in Lithuania was 10 ± 5,3 g/d. Only 12,5% of subjects consumed WHO recommended salt amount. Results varied between groups: mean salt consumption in males was 11,7 ± 5,8 g/d vs. in females 8,4 ± 4,1 g/d (p < 0,001). 35,1% of participants has hypertension. Female participants had lower mean BP (systolic 119,1 mmHg vs. 129,7 mmHg, diastolic 75,7 mmHg vs. 80,4 mmHg). Sodium excretion and male sex had significant impact on systolic blood pressure in the multiple linear regression model. Conclusions: Salt consumption in Lithuania extremely exceeds recommended amount. Females use less salt and have lower blood pressure.

Diagnostic usefulness of the spot urine sodium/potassium ratio in cirrhotic patients with ascites.

Background and aimsThe low-salt diet is considered important for control of ascites in cirrhotic patients. To validate whether the spot urine sodium (Na)/potassium (K) ratio could replace 24-h urine Na (uNa) excretion in assessing low-salt diet compliance.MethodsWe prospectively studied 175 patients. 24-h urine collection and spot urine collection were performed. Subsequently, 24-h uNa, urine creatinine (uCr), and spot urine Na and K were assessed. A complete urine collection was confirmed based on 24-h uCr excretion levels of 15mg/kg/day for men and 10mg/kg/day for women. The area under the receiver operating characteristic (AUROC) curve analysis was performed to evaluate the feasibility of spot urine Na/K ratio in predicting 24-h uNa greater than 78mmol/day.ResultsOut of 175 patients, 24-h urine samples were completely collected in 57 patients only. Moreover, urine samples were not completely collected in 118 patients because their 24-h uCr excretion level was less than the established criteria. In complete urine collection group, AUROC curve for spot urine Na/K ratio in predicting 24-h uNa greater than 78mmol/day was 0.874±0.051 (P<0.001). In the incomplete urine collection group, the AUROC was 0.832±0.039 (P<0.001). In complete urine collection group, the classical cutoff value greater than 1.0 of spot urine Na/K ratio showed 90.9% sensitivity and 56.0% specificity.ConclusionsThe spot urine Na/K ratio reflects 24-h uNa, but the AUROC value obtained in this study is lower than that of a previous study. Considered the large number of patients with incomplete urine collection, validating 24-h complete urine collection criteria is necessary.

Association of Single Nucleotide Polymorphisms in Salt Taste Receptor Genes With Dietary Salt Intake and Blood Pressure Among Iranian Adults Population

ObjectivesSo far, few researches has examined how genetic variation in salt taste receptors affects food intake in Iranian population. Thus, in this study, we aimed to investigate associations of single nucleotide polymorphisms (SNPs) in salt taste receptors genes with dietary salt intake and blood pressure. MethodsThis cross-sectional study was carried out among 116 randomly selected adults aged 18 years and over in Isfahan city, Iran. Subjects with diabetes insipidus, renal insufficiency, a special dietary regimen, fasting or menstruating on the day of sampling, using diuretics and oral contraceptives or pregnant and lactating women as well as participants who had incomplete 24-h urine collection were excluded. A 24-h urine collection and blood pressure measurement were done. Whole blood was collected to extract DNA and measure SNP rs239345 in the ENaC and rs224534, rs4790151 and rs8065080 in the TRPV1 gene. ResultsHomozygous carriers of the T allele for rs239345 were found to consume significantly more sodium (4414.7 ± 1943.8 mg/day) compared to the AA genotype (3887.4 ± 1709.1 mg/day). Further, they also had higher diastolic blood pressure compared to subjects with the AA genotype (81.3 ± 9.7 vs. 75.3 ± 8.3 mmHg). Compared to subjects with the CC genotype, those with homozygous carriers of the T allele for rs8065080 in the TRPV1 had higher sodium intake (3592.6 ± 1645.2 mg/day vs. 4604.2 ± 2013.5 mg/day) and systolic blood pressure (118.1 ± 11.3 mmHg vs. 123.4 ± 11.5 mmHg). No differences were found in dietary sodium intake and blood pressure with the rs224534 and rs4790151 SNPs. ConclusionsThese findings suggest that genetic variation in the ENaC and TRPV1 genes may contribute to inter-individual differences in salt intake and blood pressure. Funding SourcesThe National Institute for Medical Research Development (NIMAD) was funded this study via grant number of 977,549.

Augmented Renal Clearance Following Traumatic Injury in Critically Ill Patients Requiring Nutrition Therapy.

The intent of this study was to ascertain the prevalence of augmented renal clearance (ARC) in patients with traumatic injuries who require nutrition therapy and identify factors associated with ARC. Adult patients admitted to the trauma intensive care unit from January 2015 to September 2016 who received enteral or parenteral nutrition therapy and had a 24 h urine collection within 4 to 14 days after injury were retrospectively evaluated. Patients with a serum creatinine concentration > 1.5 mg/dL, required dialysis, or had an incomplete urine collection were excluded. ARC was defined as a measured creatinine clearance > 149 mL/min/1.73 m2. Two hundred and three patients were evaluated. One hundred and two (50%) exhibited ARC. A greater proportion of patients with ARC were male (86% vs. 67%; p = 0.004), had traumatic brain injury (33% vs. 9%; p = 0.001), a higher injury severity score (30 ± 11 vs. 26 ± 12; p = 0.015), were younger (36 ± 15 vs. 54 ± 17 years; p = 0.001), had a lower serum creatinine concentration (0.7 ± 2 vs. 0.9 ± 0.2 mg/dL; p = 0.001) and were more catabolic (nitrogen balance of −10.8 ± 13.0 vs. −6.2 ± 9.2 g/d; p = 0.004). The multivariate analysis revealed African American race and protein intake were also associated with ARC. Half of critically ill patients with traumatic injuries experience ARC. Patients with multiple risk factors for ARC should be closely evaluated for dosing of renally-eliminated electrolytes, nutrients, and medications.

SALT INTAKE ASSESSMENT BY 24-HOUR URINARY SODIUM EXCRETION IN LITHUANIAN POPULATION: PILOT STUDY

Objective: High salt intake is associated with increased arterial blood pressure, high risk of other preventable cardiovascular diseases, reduced life expectancy and higher mortality. WHO and the World Hypertension League strongly recommend to take less than 2000 mg of sodium (or less than 5 g of salt) per day1. However, in many countries the average daily intake of sodium still remains about 4000 mg (10 g of salt). Until now there were no investigations in Lithuania for evaluating sodium (and salt) intake in the population based on reliable methods. Aim of the study is to perform a pilot study and evaluate intake of sodium by 24-hour urinary sodium excretion and correlations with arterial blood pressure in Lithuanian population. Design and method: A study of randomly selected 237 healthy individuals of age 18–69 years old was performed. Each participant collected 24-hour urine samples and the blood pressure was measured 3 times. 15 subjects were excluded due to incomplete urine collection or incomplete data. 222 subjects were included in a statistical analysis. Results: An average salt intake was calculated using 24-hour urinary sodium excretion. The result was – 8,81 g/d [2,15; 25,54] of salt. 85% of subjects exceeded the recommended salt consumption value. Results varied between groups: mean salt consumption in males 10,77 (±4,79)g/d vs. females 7,46 (±3,41)g/d (p &lt; 0,001); in age groups &lt; 45 years old 8,57 (±3,9)g/l vs. &gt; 45 years old 9,08 (±4,69)g/d (p &gt; 0,05). A quartile classification revealed that individuals with higher salt consumption had significantly higher systolic arterial blood pressure (p = 0,02). Conclusions: A pilot study of 24-hour urinary sodium excretion revealed higher than recommended salt intake in Lithuania. Males use more salt. Higher salt intake correlates with higher blood pressure. The study will be continued to collect more detailed assessment of the population's sodium status and to formulate a public health policy strategy.

Detection and correction of incomplete duplicate 24-hour urine collections - theory and practical evidence.

IntroductionThe intraindividual variability in urinary creatinine excretion is notoriously large. The aims of this study were to investigate the variability of duplicate consecutive 24-hour urinary creatinine excretions in patients and to develop a model for the detection and correction of discrepant creatinine excretions.Materials and methodsA group of 270 patients (82 men and 188 women) were included in the study. We collected the following data: urinary 24-hour volumes (volumetric/gravimetric) and urinary creatinine concentrations (Jaffé/enzymatic) on both collection days. We performed specific calculations to detect discrepant creatinine excretions.ResultsIn 60 patients (22%) discrepant collections were found. Among the remaining 78%, 22% of the patients collected very accurately (almost identical urinary creatinine excretions). In this subgroup the volume ratios and the creatinine concentration ratios behave inversely as in a dilution curve. A theoretical model and six collection scenarios were developed to detect, interpret and correct discrepant collections. Practical examples are given to illustrate the use of the model in successful correction of creatinine and other analytes for under- or overcollection.ConclusionsWe conclude that missed or overcollected urine volumes are the largest source of variation in creatinine excretion. Discrepancies in consecutive duplicate 24-hour creatinine excretions can be detected and corrected with specific calculations by means of the presented model. The effectiveness of these corrections is demonstrated with examples from daily practice. These calculations can be easily automated.

Association of microalbuminuria and high–normal 24-hour urinary albumin excretion with metabolic syndrome and its components in the general Chinese population: cross-sectional study

ObjectiveMicroalbuminuria (MAU) has been described as a risk factor for metabolic syndrome (MetS). However, the association between MetS components with MAU and 24-hour urinary albumin excretion (UAE) has not been...

Calcium-creatinine ratio in a morning urine sample for the estimation of hypercalciuria associated with non-glomerular hematuria observed in children and adolescents.

Hypercalciuria might be revealed during the differential diagnosis of hematuria accompanying renal lithiasis (RL). In spite of this, diagnostic accuracy of calcium urinary excretion might be affected by incomplete 24-hour urine collections. In the present study, the diagnostic utility of calcium/creatinine (ICaCre) index for determining hypercalciuria associated with non-glomerular hematuria (NGH) and RL was assessed. ICaCre (mg/mg) index was calculated from calcium (mmol/l) and creatinine (µmol/l) concentrations in an aliquot from a 24-hour urine collection in 169 children and adolescents with NGH or RL. Calciuria values > 4.0 mg/kg in 24 hours were distributed according to the presence of NGH or RL. Mean ICaCre index was 0.2 ± 0.1 mg/mg. Calciuria values estimated from ICaCre were statistically higher to those from 24-hour urine collection (p < 0.05). The frequency of hypercalciuria was independent from the measurement method (estimated from ICaCre 39.5% vs. 24 h collection 32.1%; p > 0.05). Hypercalciuria distribution was as follows: no NGH + no RL: 59.0%; no NGH + RL: 60.0% (∆ = +1.0%); NGH + no RL: 68.2% (∆ = +9.2%); NGH + RL: 73.3% (∆ = +14.4%). The use of ICaCre index for determining calcium urine excretion might be effective in the study of hypercalciuria associated with NGH and RL.

Effect of monitoring salt concentration of home-prepared dishes and using low-sodium seasonings on sodium intake reduction.

Objective methods such as the monitoring of salt concentrations in home-prepared dishes may be effective in reducing salt intake. We investigated the effect of monitoring the salt concentration of home-prepared dishes (Monitoring) on salt reduction and change in taste threshold, and the effect of the simultaneous use of low-sodium seasonings (Seasoning) to compare the effect of Monitoring with the conventional method. We conducted a double-blind randomized controlled study using a 2 × 2 factorial design with two interventions. A total of 50 participants (40-75 years-old) were recruited among residents of Niigata Prefecture, a high sodium-consuming population in Japan, then randomly allocated to four groups. After excluding participants with incomplete urine collection, change in salt intake was evaluated using 24-hour urinary excretion as a surrogate of intake for 43 participants. Change in taste threshold was evaluated in 48 participants after excluding those with incomplete threshold measurement. The Monitoring intervention group showed a significant decrease in sodium intake (-777 mg/24 h), whereas the decrease in the Seasoning intervention group was not significant (-413 mg/24 h). Sodium intake did not statistically differ between the intervention and control groups (-1011 mg/24 h and -283 mg/24 h for Monitoring and Seasoning, respectively). The changes in taste threshold measurement were very small and did not markedly differ between groups. Monitoring the salt concentration of dishes had a potentially stronger salt-reducing effect than the use of low-sodium seasonings, a conventional method. Confirmation requires additional study with a larger sample size.

Association between 24h Urinary Sodium and Potassium Excretion and Estimated Glomerular Filtration Rate (eGFR) Decline or Death in Patients with Diabetes Mellitus and eGFR More than 30 ml/min/1.73m2.

BackgroundData regarding the association between 24h urinary sodium and potassium excretion with kidney outcomes in patients with diabetes mellitus is currently scarce.MethodsWe conducted a single-center, retrospective cohort study in which 1230 patients with diabetes who had undergone a 24h urinary sodium and potassium excretion test were analyzed. Patients with incomplete urine collection were excluded based on 24h urinary creatinine excretion. Outcomes were the composite of a 30% decline in eGFR or death. Multivariate cox regression analysis was used to investigate the association between urinary sodium and potassium excretion and outcomes.ResultsWith a mean follow up period of 5.47 years, 130 patients reached the outcomes (30% decline in eGFR: 124, death: 6). Mean (SD) eGFR and 24h urinary sodium and potassium excretion at baseline were 78.6 (19.5) ml/min/1.73m2, 4.50 (1.64) g/day, and 2.14 (0.77) g/day. Compared with sodium excretion < 3.0 g/day, no significant change in risk of outcomes was observed with increased increments of 1.0 g/day. Compared with potassium excretion of < 1.5 g/day, 2.0–2.5 g/day, and 2.5–3.0 g/day were significantly associated with a lower risk of outcomes (hazard ratio [HR], 0.49 and 0.44; 95% confidence interval [CI], 0.28 to 0.84 and 0.22 to 0.87).Conclusions24h urinary sodium excretion was not significantly associated with a risk of 30% decline in eGFR or death in patients with diabetes. However, an increased risk of 30% decline in eGFR or death was significantly associated with 24h urinary potassium excretion < 1.5 g/day than with 2.0–2.5 g/day and 2.5–3.0 g/day.

The Impact of Using Different Methods to Assess Completeness of 24-Hour Urine Collection on Estimating Dietary Sodium.

The standard for population-based surveillance of dietary sodium intake is 24-hour urine testing; however, this may be affected by incomplete urine collection. The impact of different indirect methods of assessing completeness of collection on estimated sodium ingestion has not been established. The authors enlisted 507 participants from an existing community study in 2009 to collect 24-hour urine samples. Several methods of assessing completeness of urine collection were tested. Mean sodium intake varied between 3648 mg/24 h and 7210 mg/24 h depending on the method used. Excluding urine samples collected for longer or shorter than 24 hours increased the estimated urine sodium excretion, even when corrections for the variation in timed collections were applied. Until an accurate method of indirectly assessing completeness of urine collection is identified, the gold standard of administering para-aminobenzoic acid is recommended. Efforts to ensure participants collect complete urine samples are also warranted.

Effects of a behavioral intervention that emphasizes spices and herbs on adherence to recommended sodium intake: results of the SPICE randomized clinical trial

For decades, dietary sodium intake in the United States has remained high, and few studies have examined strategies for maintaining recommended intakes. We examined the effects of a behavioral intervention, which emphasized spices and herbs, on the maintenance of sodium intake at the recommended intake of 1500 mg/d in individuals to whom the US Dietary Guidelines for Americans apply. We conducted a 2-phase study that included adults ≥18 y of age for whom Dietary Guidelines for Americans recommends 1500 mg Na/d. The study was conducted in Baltimore, Maryland, from 2012 to 2014. In phase 1, 55 individuals consumed a low-sodium diet for 4 wk. Participants were provided all foods, snacks, and calorie-containing drinks. In phase 2, 40 participants from phase 1 were randomly assigned to either a behavioral intervention to reduce sodium intake (n = 20) or a self-directed control group (n = 20) for 20 wk. The primary study outcome was the change in mean 24-h urinary sodium excretion during phase 2. Linear regression analyses were used to determine intervention effects on urinary sodium excretion. Participant characteristics were as follows: women: 65%; African American: 88%; hypertension: 63%; diabetes: 18%; mean age: 61 y; and mean body mass index (in kg/m(2)): 30. At the end of phase 2, mean 24-h sodium excretion was lower in the behavioral intervention than in the self-directed group (mean difference: -956.8 mg/d; 95% CI: -1538.7, -374.9 mg/d) after sodium intake at screening was controlled for (P = 0.002). These findings persisted in sensitivity analyses that excluded potentially incomplete urine collections [Mage's equation mean difference: -1090 mg/d (P = 0.001); Joosens' equation mean difference: -796 mg/d (P = 0.04)]. A multifactorial behavioral intervention emphasizing spices and herbs significantly reduced sodium intake. Because of the ubiquity of sodium in the US food supply, multilevel strategies addressing individual behaviors and the food supply are needed to improve adherence to recommendations. This trial was registered at clinicaltrials.gov as NCT01615159.

Validation and impact of a new technique for assessment of glomerular filtration rate in patients with liver disease.

Previously we have proposed a technique for the measurement of plasma clearance in patients with ascites. The impact of using the technique was assessed and the results compared with those from a reference technique in 111 patients having glomerular filtration rate measurements as part of their workup for liver transplantation. Results of calculations using the new technique were compared with plasma clearance measurements obtained using a conventional slope-intercept technique and with clearance measurements based on urine collection. Discrepancies between the results of plasma clearance and urinary clearance assessments were investigated by using an uncollimated gamma camera to measure the total retention of the tracer. Conventional slope-intercept calculations overestimated clearance compared with the new technique by more than 20% in 21% of the patients. Significant differences between the results of the two methods were more likely in patients with more severe ascites. Results of urine collection-based measurements of Cr-51 EDTA clearance were frequently significantly lower than measurements using the new technique, whereas measurements of urinary clearance of creatinine were higher. Gamma camera measurements suggest that discrepancies between total and urinary clearance of Cr-51 EDTA are due to incomplete urine collection. The new technique is a practical method for assessment of kidney function and should be used in patients with liver disease who have or may have ascites.

Abstract MP37: Effects of a Behavioral Intervention that Emphasizes Spices and Herbs on Adherence to Recommended Sodium Intake

Introduction: Adherence to the recommended dietary sodium intake is challenging given the ubiquity of sodium in the US food supply. We hypothesized that a multifactorial, behavioral intervention that emphasized spices and herbs would facilitate adherence to dietary sodium recommendations. Methods: SPICE was a two-phase study including adults, 18 years or older, for whom Dietary Guidelines for Americans recommends 1500 mg/d of sodium. In phase one, 55 individuals were fed a low sodium diet for 4 weeks to acclimatize them to eating according to dietary sodium recommendations. Participants were provided all food, snacks and calorie-containing drinks. In phase two, 40 participants from phase 1 were randomized to either a multifactorial behavioral intervention designed to reduce sodium intake (n=20) or a self-directed control group (n=20), for 20 weeks. The intervention included advice on replacing sodium with spices and herbs. The primary study outcome was 24-hour urinary sodium excretion. We used linear regression analyses to determine the effects of the intervention on urinary sodium excretion. Results: Participants were 65% female, 88% African American; 63% had hypertension, 18% had diabetes; mean(sd) age was 61(9.7) years, and BMI was 30(8.9) kg/m 2 . During phase one (controlled feeding), mean 24-hour urinary sodium excretion decreased (150 mmol/d to 72 mmol/d). At the end of the 20-week behavioral intervention, 24-hour urinary sodium excretion increased in both arms but was 42 mmol/d lower in the intervention group than in the control group, p=0.002 (Figure). These findings were robust to methods excluding incomplete urine collections (Mage equation: mean difference -47.4, p=0.001, Joosens equation: mean difference -34.6, p=0.04). Conclusions: A multi-factorial behavioral intervention that emphasizes spices and herbs facilitates adherence to the recommended dietary sodium intake.

Problems in methods for the detection of significant proteinuria in pregnancy

The aim of this study was to underscore problems associated with the dipstick test and determination of protein concentration alone in spot-urine (P-test) compared with spot-urine protein-to-creatinine ratio (P/Cr test) and to determine whether urine collection for 24-h test was complete. Dipstick and P/Cr tests were performed simultaneously in 357 random spot-urine specimens from 145 pregnant women, including 35 with pre-eclampsia. Positive results were defined as ≥ 1+ on dipstick test, protein concentration ≥ 30 mg/dL on P-test, and P/Cr ratio ≥ 0.27 (mg/mg) on P/Cr test. Sixty-four 24-h urine tests (quantification of protein in urine collected during 24 h) were performed in 27 of the 145 women. We assumed that P/Cr ratio ≥ 0.27 predicted significant proteinuria (urinary protein ≥ 0.3 g/day). The 24-h urine collection was considered incomplete when urinary creatinine excretion was <11.0 mg/kg/day or >25.0 mg/kg/day. Forty-four percent (69/156) of specimens with a positive test result on dipstick test contained protein < 30 mg/dL. Dipstick test was positive for 25.7% (69/269) of specimens with protein < 30 mg/dL and for 28.8% (79/274) of specimens with P/Cr ratio < 0.27. P-test results were positive for 7.3% (20/274) and negative for 18.1% (15/83) of specimens with P/Cr ratio < 0.27 and ≥ 0.27, respectively. Incomplete 24-h urine collection occurred in 15.6% (10/64) of 24-h urine tests. Daily urinary creatinine excretion was 702-1397 mg, while creatinine concentration varied from 16 mg/dL to 475 mg/dL in spot-urine specimens. Dipstick test and P-test were likely to over- and underestimate risks of significant proteinuria, respectively. The 24-h urine collection was often incomplete.