Urinary Creatinine Excretion Research Articles

Predicting adverse outcomes in hypertensive obstetric cases by using spot urine calcium: Creatinine ratio

Background: Hypertensive disorders complicate upto 5-10% of pregnancies, 3.9% is preeclampsia the leading cause of both direct maternal and perinatal mortality. Mostly preeclampsia is diagnosed only after pathological changes are already established. The study being carried out to investigate the significance of urinary calcium-creatinine ratio in predicting the outcomes with hypertensive disorder of pregnancy. Methods: All women between the gestational ages 20 -28 weeks were taken into the study, spot urine sample was taken to measure the urinary calcium-creatinine-ratio. Ratio less than or equal to 0.04 was considered test positive and those with ratio of >0.04 was considered test negative.Results: 218 normotensive, 17Gestational hypertension, and 21 Preeclampsia were recruited fir the study. Urinary creatinine excretion among gestational hypertension and preeclampsia is more than normotensive women. Calcium excretion is low in preeclampsia compared to normotensive women. CCR was positive 87.69% of preeclampsia and 40% in gestational hypertension. We found that CCR was a better predictor of preeclampsia than gestational hypertension, with sensitivity of 73.81%, specificity of 95.18%.More maternal complications such as abnormal Doppler studies and HELLP syndrome among preeclampsia, and lower birth weight were noted among women with preeclampsia. More number of abnormal APGAR at 1’ and 5’ were noted in preeclampsia group.Conclusion: Spot Urine calcium-creatinine ratio of ≤0.04 in asymptomatic pregnant women between 20-28 weeks of pregnancy is a good predictor for hypertensive disorders of pregnancy, especially preeclampsia. We can also conclude that there is increased maternal and fetal morbidity among women complicated with hypertension than normotensive women.

A Formula for the Estimation of 24-Hour Urinary Creatinine Excretion: A Derivation and Validation Study

Twenty-four-hour urinary creatinine (Cr) excretion (24h-uCr) is the basis of Cr clearance and urinary protein-Cr ratio, and it is related to frailty, worsening kidney function, and mortality in patients with chronic kidney disease. Although subjects with lower estimated glomerular filtration rate (eGFR) tend to have lower 24h-uCr, previous formulae for the estimation of 24h-uCr did not include Cr as a predictor. This retrospective study included patients admitted to the Department of Nephrology at our hospital (derivation cohort and validation cohort: patients admitted between April 2016 and March 2020). The prediction formula of 24h-uCr was calculated using a multivariate linear regression model with the bootstrap method. Age, height, weight, sex, Cr, and cystatin C were used as predictors. The derivation and validation cohorts included 187 and 63 patients, respectively. The characteristics of the derivation and validation cohorts were as follows: age 73 (61-79.5) years and 70 (58.5-79) years; males, 61.5% and 60.3%; eGFRCr 27.0 (13.7-48.6) mL/min/1.73m2 and 26.3 (14.0-51.5) mL/min/1.73m2; and 24-hour urinary protein excretion 0.79 (0.17-2.12) g/day and 1.08 (0.26-2.55) g/day, respectively. Seven prediction formulae were derived. In all models, the Pearson's correlation coefficient was relatively high and statistically significant. However, previous models tended to overestimate the 24h-uCr. Furthermore, the predicted 24h-uCr calculated by the models that do not include Cr as a predictor fluctuates depending on the eGFRCr. The best formula for predicting 24h-uCr (mg/day) in a wide range of eGFR populations is a Cr-containing formula: [-9.04×age (years)+8.03×weight (kg)+0.66×height (cm)+188.59 (if male) - 32.11×Cr (mg/dL)+779.14].

Immunotropic effects of nitrogenous metabolites in patients with chronic pyelonephritis

Background. We have previously shown that nitrogenous metabolites have immunomodulatory effects in healthy rats and humans as well as in patients with encephalopatia. The purpose of this study is their immunotropic activity in patients with chronic pyelonephritis. Materials and Methods. The object of observation were 24 men (aged 23-76 years) with chronic pyelonephritis in remission. The plasma levels and urinary excretion of uric acid, urea and creatinine and parameters of immunity twice (on admission and after 10 days of balneotherapy at the Truskavets’ Spa) was performed. Results. Judging by the multiple correlation coefficient uricemia exhibits maximal immunotropic activity (R=0,772), followed by creatininemia (R=0,643), urea plasma (R=0,584) and creatinineuria (R=0,506) instead, urea and uric acid excretion correlate with immune parameters insignificantly (R=0,327 and 0,262 respectively). Nitrogenous metabolites together upregulate most parameters of phagocytosis by neutrophils Staph. aureus and E. coli, the level in the blood of CD8 T-lymphocytes, CIC, IgM, componentes of leukocytogram as well as entropy of leukocytogram and immunocytogram. Instead, they downregulate the relative level of lymphocytes in general and of CD4 T-lymphocytes in particular. Conclusion. Nitrogenous metabolites exhibit immunotropic activity in both healthy humans and in patients with chronic pyelonephritis in remission. Both common and distinctive features of immunomodulation were revealed.

Anti-urolithiatic activity of Bryophyllum pinnatum Lam. hydroalcoholic extract in sodium oxalate-induced urolithiasis in rats

Background and AimDespite advances in modern medicine, the development and growth of calculi continues to be a source of concern for mankind, as there is no effective treatment for kidney stones. In the present study we investigated antiurolithiatic activity of Bryophyllum pinnatum Lam against sodium oxalate (NaOx) induced urolithiasis in rats.Experimental procedureIn rats with renal calculi caused by sodium oxalate (NaOx, 70 mg/kg, i.p.); the antiurolithiatic action of Bryophyllum pinnatum hydroalcoholic extract (BPHE) was studied. BPHE was given every day orally at doses of 50, 200 mg/kg for 14 days to rats to examine activity against sodium oxalate (NaOx) mediated urolithiasis, with Cystone (500 mg/kg, p.o.) as a reference standard. The effect of the extract on urine oxalate, creatinine and phosphate retention and excretion in the kidney, as well as serum and biochemical analysis of kidney homogenate and histopathological examinations were studied.Results and conclusionOral administration of BPHE at doses of 50,100, and 200 mg/kg to rats with sodium oxalate-mediated renal calculi showed dose-dependent substantial (P<0.05) antiurolithiatic potential, with notable reversal of NaOx-induced ion excretion and urinary CaOx concentration. These findings justify the traditional use of Bryophyllum pinnatum hydroalcoholic extract (BPHE) in the treatment of renal calculi.

Protective Role of Fisetin in STZ Induced Diabetic Nephropathy in Rats

Objectives: Chronic diabetes mellitus associated with devastating complication the diabetic nephropathy, that further progress to ESRD,a major cause of morbidity and premature mortality in many countries worldwide. Accumulated evidences demonstrated that long standing hyperglycemia induced oxidative stress, inflammatory cytokines, and fibrosis plays a significant role in DN. Fisetin, a bioflavonoid, exhibited variety of promising pharmacological properties such as, anti-diabetic, antioxidant, anti-inflammatory, anti-hyperlipidemic ,and anti-carcinogenics. Hence, the present study was hypothesized to investigate, the effect of fisetin on streptozotocin-induced diabetic nephropathy in rats.&#x0D; Materials and Methods: Sprague Dawley rats were divided into 6 groups (n=6) as normal control, diabetic control (vehicle), Glimepiride (0.5 mg/kg, orally) and Fisetin treatment (2.5, 5 and 10 mg/kg, orally) groups. After the confirmation of diabetes, vehicle/drug treatments were started and continued for 6 weeks. Serum glucose, body weight, were measured on weekly basis.Thereafter, on the last day of treatment protocol, ie 42 day, serum insulin, HbA1c in blood, lipid parameters, creatinine, albumin and urea in serum and in urine creatinine excretion, albumin were measured along with urine volume and creatinine clearance. In addition, weight of kidney and histopathological studies were carried out.&#x0D; Results: Fisetin treatment significantly attenuated reduction in body weight. Also, it significantly decreased the blood glucose level, ameliorate lipid profile and HbA1c (p&lt;0.05) value, but serum insulin level were not much influenced. It also increased albumin in serum, decreased serum urea and creatinine and in urine, it reduced the urine volume, albumin with marked improvement in creatinine excretion and creatinine clearance. Further, the fisetin (10mg/kg) treatment attenuated oxidative stress and cytokines TNF-α (p&lt;0.01), IL-1β (p&lt;0.01), and IL-6 (p&lt;0.05) level in kidney tissue along with amelioration of histopathological alterations compared to diabetic control rats. The standard drug, glimepiride also exhibited similar antidiabetic effect without much influence on oxidative stress, albumin in urine, and cytokine levels.&#x0D; Conclusions: The results indicated that fisetin ameliorated diabetic nephropathy through its antidiabetic and antioxidant effect which may be attributed to inhibition of downward pathway of glycemia induced oxidative stress, inflammation and necroptosis of renal tissue.

Effects of guanidinoacetic acid supplementation on nitrogen retention and methionine flux in cattle.

Creatine stores high-energy phosphate bonds in muscle and is synthesized in the liver through methylation of guanidinoacetic acid (GAA). Supplementation of GAA may therefore increase methyl group requirements, and this may affect methyl group utilization. Our experiment evaluated the metabolic responses of growing cattle to postruminal supplementation of GAA, in a model where methionine (Met) was deficient, with and without Met supplementation. Seven ruminally cannulated Holstein steers (161 kg initial body weight [BW]) were limit-fed a soybean hull-based diet (2.7 kg/d dry matter) and received continuous abomasal infusions of an essential amino acid (AA) mixture devoid of Met to ensure that no AA besides Met limited animal performance. To provide energy without increasing the microbial protein supply, all steers received ruminal infusions of 200 g/d acetic acid, 200 g/d propionic acid, and 50 g/d butyric acid, as well as abomasal infusions of 300 g/d glucose. Treatments, provided abomasally, were arranged as a 2 × 3 factorial in a split-plot design, and included 0 or 6 g/d of l-Met and 0, 7.5, and 15 g/d of GAA. The experiment included six 10-d periods. Whole body Met flux was measured using continuous jugular infusion of 1-13C-l-Met and methyl-2H3-l-Met. Nitrogen retention was elevated by Met supplementation (P < 0.01). Supplementation with GAA tended to increase N retention when it was supplemented along with Met, but not when it was supplemented without Met. Supplementing GAA linearly increased plasma concentrations of GAA and creatine (P < 0.001), but treatments did not affect urinary excretion of GAA, creatine, or creatinine. Supplementation with Met decreased plasma homocysteine (P < 0.01). Supplementation of GAA tended (P = 0.10) to increase plasma homocysteine when no Met was supplemented, but not when 6 g/d Met was provided. Protein synthesis and protein degradation were both increased by GAA supplementation when no Met was supplemented, but decreased by GAA supplementation when 6 g/d Met were provided. Loss of Met through transsulfuration was increased by Met supplementation, whereas synthesis of Met from remethylation of homocysteine was decreased by Met supplementation. No differences in transmethylation, transsulfuration, or remethylation reactions were observed in response to GAA supplementation. The administration of GAA, when methyl groups are not limiting, has the potential to improve lean tissue deposition and cattle growth.

MO597ESTIMATING INDIVIDUAL-LEVEL SODIUM INTAKE WITH REPEATED SPOT URINE SAMPLING

Abstract Background and Aims In daily clinical practice, individual-level sodium (Na) intake is often estimated by measuring Na excretion in a single 24h urine collection, but long-term Na balance studies indicate that 7 consecutive 24h urine collections are needed. However, this approach is not feasible in clinical settings. In this study, we investigate whether the use of repeated spot urine sampling is an appropriate alternative for repeated 24h urine collections. Method We performed a post-hoc analysis of a metabolic ward study in 8 healthy male adults who consumed a 7-day diet with a fixed amount of Na (200 mmol/d). Urine was collected in four daily intervals: 7-13h, 13-19h, 19-23h and 23-7h. After reaching steady state, we estimated Na intake with 1 and 3 consecutive 24h urine collections and 3-day spot urine sampling, using the Kawasaki formula with measured 24h urine creatinine excretion. Results: On day 5, mean 24h Na excretion matched intake, indicating that steady state was achieved (Fig A). Mean and standard deviation of absolute differences between estimated and measured Na intake (ΔNa) for each method were: 18.8 ±14.6 mmol (3 x spot urine 7-13h), 32.3 ±18.7 mmol (3 x spot urine 13-19h), 74.6 ±30.0 mmol (3 x spot urine 19-23h), 28.2 ±19.8 mmol (3 x spot urine 23-7h), 29.8 ±23.9 mmol (1 x 24h urine) and 22.9 ±11.3 mmol (3 x 24h urine) (Fig B). With the exception of the 19-23h spot urine collection period, the accuracy of 3-day spot urine sampling did not significantly differ from accuracy of 1 and 3 consecutive 24h urine collections. When combining the pre-night and morning spot urine collections (19-7h), the accuracy of the estimation did not improve (ΔNa 28.7 ±19.6 mmol). Conclusion 3-day spot urine sampling did not perform significantly different than 1 and 3 24h urine collections for estimation of individual-level Na intake. Adequately powered studies need to confirm whether repeated spot urine sampling is an accurate and low burden alternative to repeated 24h urine collections.

Associations Between Surrogates of Skeletal Muscle Mass and History of Bone Fracture in Patients with Chronic Kidney Disease: The Fukuoka Kidney disease Registry (FKR) Study.

Patients with chronic kidney disease (CKD) are at increased risks of both sarcopenia and fragility fractures. However, information on the association between skeletal muscle mass (SMM) and the risk of bone fractures in patients with CKD is lacking. We performed a cross-sectional analysis of 4146 patients with CKD using the baseline dataset of the Fukuoka Kidney disease Registry Study, as a multicenter, prospective cohort study of pre-dialysis CKD patients. The main measure was estimated SMM (eSMM) calculated using an equation validated by bioelectrical impedance analysis with two independent datasets of 100 and 81 CKD patients. The main outcome was historical bone fractures. The associations between sex-specific quartiles (Q1-Q4) of eSMM and fracture history were assessed by logistic regression analyses. The prevalence of a history of fractures increased and eSMM decreased with progressive CKD stages. Among the 4146 patients, 249 had prior bone fractures, including 111 patients in Q1 (lowest quartile), 65 in Q2, 46 in Q3, and 27 in Q4 (highest quartile). A multivariable-adjusted model revealed that patients in Q1 had a significantly higher odds ratio (95% confidence interval) for bone fracture history than those in Q4 (reference): Q1, 2.77 (1.32-5.80); Q2, 1.95 (1.05-3.65); and Q3, 1.57 (0.90-2.75) (P-value for trend < 0.001). Similar associations were obtained when other skeletal muscle surrogates were applied: serum creatinine to serum cystatin C and daily urinary creatinine excretion. These results suggest that a lower eSMM is associated with an increased prevalence of historical bone fractures in pre-dialysis CKD patients.

Sodium Intake and Proteinuria/Albuminuria in the Population-Observational, Cross-Sectional Study.

Sodium effects on proteinuria are debated. This observational, cross-sectional, population-based study investigated relationships to proteinuria and albuminuria of sodium intake assessed as urinary sodium/creatinine ratio (NaCR). In 482 men and 454 women aged 35–94 years from the Moli-sani study, data were collected for the following: urinary NaCR (independent variable); urinary total proteins/creatinine ratio (PCR, mg/g), urinary albumin/creatinine ratio (ACR, mg/g), and urinary non-albumin-proteins/creatinine ratio (calculated as PCR minus ACR) (dependent variables). High values were defined as PCR ≥ 150 mg/g, ACR ≥ 30 mg/g, and urinary non-albumin-proteins/creatinine ratio ≥ 120 mg/g. Urinary variables were measured in first-void morning urine. Skewed variables were log-transformed in analyses. The covariates list included sex, age, energy intake, body mass index, waist/hip ratio, estimated urinary creatinine excretion, smoking, systolic pressure, diastolic pressure, diabetes, history of cardiovascular disease, reported treatment with antihypertensive drug, inhibitor or blocker of the renin-angiotensin system, diuretic, and log-transformed data of total physical activity, leisure physical activity, alcohol intake, and urinary ratios of urea nitrogen, potassium, and phosphorus to creatinine. In multivariable linear regression, standardized beta coefficients of urinary NaCR were positive with PCR (women and men = 0.280 and 0.242, 95% confidence interval = 0.17/0.39 and 0.13/0.35, p < 0.001), ACR (0.310 and 0.265, 0.20/0.42 and 0.16/0.38, p < 0.001), and urinary non-albumin-proteins/creatinine ratio (0.247 and 0.209, 0.14/0.36 and 0.09/0.33, p < 0.001). In multivariable logistic regression, higher quintile of urinary NaCR associated with odds ratio of 1.81 for high PCR (1.55/2.12, p < 0.001), 0.51 of 1.62 for high ACR (1.35/1.95, p < 0.001), and of 1.84 for high urinary non-albumin proteins/creatinine ratio (1.58/2.16, p < 0.001). Findings were consistent in subgroups. Data indicate independent positive associations of an index of sodium intake with proteinuria and albuminuria in the population.

Spot Urine Formulas to Estimate 24-Hour Urinary Sodium Excretion Alter the Dietary Sodium and Blood Pressure Relationship.

[Figure: see text].

DISTRIBUTION OF SPOT URINARY ELECTROLYTES AND THEIR PREDICTED 24 HOUR LEVELS BY ETHNICITY ASSOCIATIONS WITH MORTALITY IN A LONGITUDNAL COHORT

Objective: Hypertension is a modifiable risk factor for development of cardiovascular disease. Increased urinary sodium excretion, representing high dietary sodium intake is associated with hypertension. Observational cohort studies consistently demonstrate a low sodium intake is also associated with increased mortality. It is not known what the optimal amount of salt intake is good for cardiovascular health. Hypertension is a modifiable risk factor for development of cardiovascular disease. Increased urinary sodium excretion, representing high dietary sodium intake is associated with hypertension. Observational cohort studies consistently demonstrate a low sodium intake is also associated with increased mortality. It is not known what the optimal amount of salt intake is good for cardiovascular health. Design and method: Urine samples were obtained from 331 people [100 Afro-Caribbean (AC), 118 European and 113 Gujarati Indians] to estimate 24-hour sodium and potassium excretion. Association between estimated urinary sodium, potassium and creatinine excretion to composite outcome of major cardiovascular event and death were examined. We also aimed to study if ethnicity influenced this relationship. Results: We noted heterogeneity in association between sodium, potassium, creatinine excretion and mortality. Significantly higher, age-sex adjusted, spot urinary sodium (OR- 2.7; CI – 1.9–3.2) and creatinine (OR- 1.7; CI – 1.2–2.2) levels were seen in AC men who also had higher mean diastolic blood pressure (84 ± 5.5 vs 78 ± 3.3; p &lt; 0.05). Overall, 42.9% (n = 142) of the cohort were hypertensive. Of the 331 eligible participants at baseline, a total 69 cardiovascular deaths were recorded. Spot sodium levels were higher in those who died from cardiovascular causes [(125.3; CI- 116.9, 133.7) mmol/l] vs [(108.7; CI - 99.4 – 118.0); p = 0.02]. Survival was associated with a urinary sodium below and urinary potassium above the median. There was no survival advantage associated with differences in creatinine output. Conclusions: This study estimates a sodium intake of between 2.0 g/day and 2.5 g/day as being associated with a lower risk of death and cardiovascular events. A higher potassium excretion was associated with a lower risk of death and cardiovascular events. Creatinine output made no difference to survival advantage.

ACCURATE ESTIMATION OF INDIVIDUAL SODIUM INTAKE WITH REPEATED SPOT URINE SAMPLING

Objective: In clinical practice, individual sodium (Na+) intake is estimated by measuring Na+ excretion in one 24-h urine collection (UC), whereas long-term Na+ balance studies indicate that 7 consecutive 24-h UCs may be needed. In this study, we investigate whether the use of repeated spot UCs is an appropriate alternative for multiple 24-h UCs to estimate Na+ intake. Design and method: We performed a post-hoc analysis of a metabolic ward study in 8 healthy male adults who consumed a 7-d diet with a fixed amount of 200 mmol/d Na+. Urine was collected in 4 daily intervals (7–13 h, 13–19 h, 19–23 h and 23–7 h). After reaching steady state, we estimated Na+ intake by single and repeated 24-h UCs and repeated spot UCs, using the Kawasaki formula with measured 24-h urine creatinine excretion. Results: At day 5, mean 24-h Na+ excretion matched intake, indicating that steady state was achieved (Fig 1A). Mean absolute differences (δ) between measured Na+ intake and 3-d spot UC estimates were 18.8 (SD 14.6), 32.3 (SD 18.7), 74.6 (SD 30.0) and 28.2 (SD 19.8) mmol for interval 7–13 h, 13–19 h, 19–23 h and 23–7 h, respectively (Fig 1B). With the exception of samples collected between 19–23 h, Na+ intake estimates by 3-d spot UCs did not significantly differ from Na+ intake estimates by single (δ 29.8 mmol; SD 23.9) and three 24-h UCs (δ 22.9 mmol; SD 11.4). Figure 1. (A) Mean 24-h Na+ excretion during 7-d diet. (B) Comparison of the performance of three consecutive spot UCs (blue), single 24-h UC (green) and three consecutive 24-h UCs (red) for estimating Na+ intake (200 mmol/d). Absolute differences (δ) between estimated and measured Na+ intake. Data are mean and SD. Conclusions: In this 7-d Na+ balance study, repeated spot UCs performed similar to a single and repeated 24-h UCs in estimating Na+ intake. Adequately powered studies need to confirm whether repeated spot UCs are an accurate and low burden alternative to 24-h UCs.

24 h urinary creatinine excretion during pregnancy and its application in appropriate estimation of 24 h urinary iodine excretion

Urinary creatinine can be used to adjust urinary iodine to evaluate iodine nutritional status during pregnancy. However, the reference intervals and impact factors of urinary creatinine are unknown. 24 h urine creatinine concentration (24 hUCr) and spot UCr at four different time periods of the day of pregnant women from Part 1 (n = 743) were measured. Linear regression analysis was performed to identify the impact factors of 24 h urinary creatinine excretion (24 hUCrE) and obtain the estimated 24 h urinary creatinine excretion (24 hUCrEest). Then measured urinary iodine concentration (UIC) of 24 h and at fasting of pregnant women from Part 2 (n = 325), used spot urinary iodine to creatinine concentration ratio (UIC/UCr) and 24 hUCrEest to calculate the estimated 24 h urinary iodine excretion (24 hUIEest), finally checked the consistency and correlation of 24 hUIEest and 24 h urinary iodine excretion (24 hUIE). In Part 1, the median 24 hUCrE was 1.24(IQR0.98-1.76)g, and the reference interval was 0.61-2.93 g. The median 24 hUCr was 0.76 (IQR0.57-1.01)g/L, and the reference interval was 0.36-1.88 g/L. Multiple linear regression results showed that pregnancy weight was an influencing factor to 24 hUCrE after adjusting by gestational weeks, age, pre-pregnancy BMI, and percentage of body fat (F = 45.029, p＜0.001). In Part 2, there was no statistically significant difference between 24 hUIEest and 24 hUIE (Z =-0.767, p = 0.443). Using 24hUIE as the gold standard, the relative average difference in 24hUIEest was 4.2 %, the relative average differences for UIC and UIC/UCr were 32.4 % and 37.2 %. The reference interval of 24 hUIE and 24 hUIEest were 88.43-585.90 μg and 50.97-700.39 μg, respectively. The reference intervals of 24 hUCrE, spot UCr, 24 hUIE, and 24 hUIEest during pregnancy were established. 24 hUCrE has important application value in iodine nutrition evaluation to gain more lead time for pregnant women with iodine nutrition-related diseases.

Cosinor-rhythmometry for 24-h urinary sodium, potassium, creatinine excretion in the Chinese adult population.

Background:The low accuracy of equations predicting 24-h urinary sodium excretion using a single spot urine sample contributed to the misclassification of individual sodium intake levels. The application of single spot urine sample is limited by a lack of representativity of urinary sodium excretion, possibly due to the circadian rhythm in urinary excretion. This study aimed to explore the circadian rhythm, characteristics, and parameters in a healthy young adult Chinese population as a theoretical foundation for developing new approaches.Methods:Eighty-five participants (mean age 32.4 years) completed the 24-h urine collection by successively collecting each of the single-voided specimens within 24 h. The concentrations of the urinary sodium, potassium, and creatinine for each voided specimen were measured. Cosinor analysis was applied to explore the circadian rhythm of the urinary sodium, potassium, and creatinine excretion. The excretion per hour was computed for analyzing the change over time with repeated-measures analysis of variance and a cubic spline model.Results:The metabolism of urinary sodium, potassium, and creatinine showed different patterns of circadian rhythm, although the urinary sodium excretion showed non-significant parameters in the cosinor model. A significant circadian rhythm of urinary creatinine excretion was observed, while the circadian rhythm of sodium was less significant than that of potassium. The circadian rhythm of urinary sodium and creatinine excretion showed synchronization to some extent, which had a nocturnal peak and fell to the lowest around noon to afternoon. In contrast, the peak of potassium was observed in the morning and dropped to the lowest point in the evening. The hourly urinary excretion followed a similar circadian rhythm.Conclusion:It is necessary to consider the circadian rhythm of urinary sodium, potassium, and creatinine excretion in adults while exploring the estimation model for 24-h urinary sodium excretion using spot urine.

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.

Performance of formulas for the evaluation of 24-hour urine collections using urine creatinine excretion

Creatinine excretion is widely used as a method to evaluate the adequacy of urine collection in different clinical settings. Many factors influence its elimination, such as protein intake, exercise, muscle mass, age, and sex, among many others. As 24-hour urine collections can be cumbersome, several equations have been developed to aid clinicians to correctly interpret results derived from them. In this review article, we report the factors that can modify creatinine excretion and we evaluate the accuracy of different published equations to estimate 24-hour urine creatinine excretion.

FURTHER STUDIES ON URINARY 3-METHYLHISTIDINE EXCRETION AS AN INDIRECT INDEX OF DIETARY AMINO ACID ADEQUACY IN RATS

As a further step in the determination of the sen­sitivity of urinary 3-methylhistidine (3-MeH) to essential amino acid adequacy in diet, 36 male albino rats of the Wistar strain were divided into six groups +of six rats per group. Each group with an initial .mean live weight of 106.52 ± 0.54g was fed in in­dividual metabolic cages on a basal diet sup­plemented with graded levels of DL-methionine. Total methionine in diet ranged between 0.25 and 1.05%. The study lasted 10 days. The response of urinary 3-methylhistidine excretion to the graded levels of methionine in diet was compared to responses obtained from growth performance characteristics, plasma urea concentration, liver nitrogen and creatinine excretion. With the excep­tion of feed intake, all other indices of dietary pro­tein adequcy and efficient amino acid utilization viz growth rate, protein efficiency ratio, serum urea concentration, and creatinine excretion were significantly (P 0.05) to P 0.01) influenced by dietary methionine level. Maximum growth rate, liver N and urinary 3-methylhistidine were observed. in rats given 0.45% total methionine in diet. Supplementing the basal diet to contain 0.45% total,' methonine significantly (P 0.01) decreased serum urea concentration. Urinary 3-methylhistidlne excre­tion was found by regression analysis to be positively correlated to body weight gain (r = 0.73), feed intake (r = 0.61), urinary creatinine excretion (r = 0.74) and liver N (0.72) but negatively correlated to dietary methionine level (r = —0.41). We suggested that urinary 3-MeH excretion be added to the list of available indicts for dietary amino acid adequacy.

Prevalence of sarcopenic obesity and sarcopenic overweight in the general population: The lifelines cohort study

Sarcopenic obesity (SO) is defined by a relatively low muscle mass in combination with obesity. Sarcopenic obesity was first noted as a health risk in geriatric populations but has recently been recognized as a scientific and clinical priority that may extend beyond geriatric settings. Obesity is generally preceded by overweight, so the prevalence and health risks of sarcopenia in those with overweight (SOW) is of interest for preventive purposes. The aim of this study, therefore, was to assess the prevalence and determinants of SO and SOW in a general population. Participants (n=119,494), aged 18-90 years were included from the Dutch Lifelines cohort study. Muscle mass was assessed by 24-h urine creatinine excretion and stratified for gender for analysis, and obesity was defined as a Body Mass Index (BMI) ≥30kg/m2 and overweight ≥25kg/m2. Multivariate logistic regression models were applied to assess the relevant determinants of SO and SOW. Respectively for men and women the prevalence of SO was 0.9% and 1.4%, and prevalence of SOW 6.5% and 6.0%. In subjects with sarcopenia, BMI was ≥25kg/m2 in 45.5% and ≥30kg/m2 in 6.1%. Overall females had a higher prevalence of SOW and SO in all age groups except for SOW in males between ages 40-59. Also, age was a significant determinant of SO and SOW, with a rise in prevalence as of age 50. Of all subjects with SO and SOW, respectively 82.5% and 80.4% were below the age of 70. Compared to those with no morbidities, the odds ratio of SO and SOW among participants with >3 comorbidities was 2.71 (95% CI: 1.62-4.54) and 1.33 (95% CI: 1.07-1.65) among males and 1.14 (95% CI: 0.79-1.65) and 1.28 (95% CI: 1.06-1.54) among females, independent of other determinants. Overall, an inverse association was found between SOW and SO and physical activity and macronutrient intake. The results support the need for more awareness of SO beyond the field of geriatrics, in particular in subjects with comorbidities. SOW is more prevalent than SO and may provide opportunities for preventive strategies for the general population.

Is Water-Only Fasting Safe?

BackgroundWater-only fasting (WF) is a practice used to improve and maintain health.ObjectiveThe aim of the study was to show whether WF performed for 8 days may be a threat to the health and/or life of people undergoing this practice.MethodsTwelve middle-aged men participated in the study. During the 8-day WF, the subjects ate no food except for drinking mineral water. Before and after WF, all subjects had a series of tests performed, beginning with the level of perceived stress and somatic measurements. The concentrations of creatinine, sodium (Na+), potassium (K+), total calcium (Ca), magnesium (Mg++), urea (U), uric acid (UA) and total protein were determined in this urine and in the serum. For these substances, the values ​​of clearance, renal filtration and fractional excretion were calculated. The osmotic clearance and free water clearance as well as the amount of daily urinary excretion of creatinine, Na+, K+, Ca, Mg++, U and UA were also calculated. Moreover, the concentration of glucose in the serum and the concentration of β-hydroxybutyrate in the plasma were determined. In urine, specific gravity, pH and osmolality were also measured.ResultsAfter 8 days of WF, the study showed a significant reduction in the level of perceived stress, weight loss, changes in body composition, dehydration, increased ketogenesis, hyperuricemia, decreased serum glucose concentration, and hyponatremia. These changes were accompanied by Na+, K+ and protein sparing, decreased serum Ca and Mg++ concentrations, and reduced daily volume of more acidic urine with elevated specific gravity.ConclusionsAfter 8 days of WF, all subjects were found to remain safe and feel the sense of well-being. However, the appearance of the above-mentioned adverse metabolic effects, despite partially effective renal compensations, suggests that the further continuation of fasting intervention by the subjects would be detrimental to their body.

Malnutrition according to GLIM criteria in stable renal transplant recipients: Reduced muscle mass as predominant phenotypic criterion

Malnutrition has a negative impact on quality of life and survival in renal transplant recipients (RTR). Therefore, malnutrition detection is important in RTR, but this may be hampered by concomitant presence of weight gain and overweight. Recently, the Global Leadership Initiative on Malnutrition (GLIM) developed a set of diagnostic criteria for malnutrition. We aimed to assess the prevalence of malnutrition according to the GLIM criteria and the distribution of phenotypic criteria in RTR. Additionally, we examined the potential value of 24-h urinary creatinine excretion rate (CER) as alternative measure for the criterion reduced muscle mass. We used data from stable outpatient RTR included in the TransplantLines Cohort and Biobank Study (NCT02811835). Presence of weight loss and reduced intake or assimilation were derived from Patient-Generated Subjective Global Assessment (PG-SGA) item scores. Reduced muscle mass was assessed by multi-frequency bio-electrical impedance analysis (MF-BIA) and defined as an appendicular skeletal muscle mass index (ASMI)<7kg/m2 for men and <5.5kg/m2 for women, and in additional analysis defined as creatinine-height index (CHI, based on 24h urine CER)<80%. Inflammation was present if C-reactive protein (CRP) was >5mg/L. Malnutrition was defined as presence of at least one phenotypic (weight loss and/or low BMI and/or reduced muscle mass) and one etiologic criterion (reduced intake/assimilation and/or disease burden/inflammation). We included 599 RTR (55±13 years old, 62% male, BMI 27.2±4.7kg/m2) at a median of 3.1 years after transplantation. According to GLIM criteria, 14% was malnourished, of which 91% met the phenotypic criterion for reduced muscle mass. Similar results were found by using CHI as measure for muscle mass (13% malnutrition of which 79% with reduced muscle mass). Malnutrition is present in one in 7 stable RTR, with reduced muscle mass as the predominant phenotypic criterion. Assessment of nutritional status, most importantly muscle status, is warranted in routine care, to prevent malnutrition in RTR from remaining undetected and untreated. The diagnostic value of 24-h urinary CER in this regard requires further investigation.