24-hour Urinary Creatinine Research Articles

Kidney Health Consequences of Patients with Glomerulonephritis; Before and After SARS-COV2 Infection

Objective: The virus that causes severe acute respiratory syndrome (SARS-CoV-2) was first identified in Wuhan, China, in December 2019. Recent studies have proven that SARS-CoV-2 is also a nephrotrophic virus. Methods: Our study aimed to evaluate kidney function and general kidney health of patients with previously diagnosed glomerular diseases and follow-up after SARS-CoV-2 infection. For this purpose, the data of 36 patients who were diagnosed with and routinely followed up for glomerulonephritis and had SARS-CoV-2 infection at the Kocaeli University Faculty of Medicine Hospital nephrology outpatient clinics between January 2020 and January 2022 were examined before and after the infection. Results: No significant differences were observed in serum creatinine, estimated glomerular filtration rate, and 24-hour urine protein values after infection. There was an increase in platelet and albumin levels following the SARS-CoV-2 infection. A significant decrease was detected in 24-hour urine creatinine values. Conclusion: The results of the study showed that kidney function and general kidney health of patients with SARS-CoV-2 infection diagnosed with glomerulonephritis were not different when compared to their condition before SARS-CoV-2 infection.

Muscle Mass, Muscle Strength, and Health-Related Quality of Life in Kidney Transplant Recipients: Results of the TransplantLines Biobank and Cohort Study

IntroductionMuscles are crucial for daily activities, and kidney transplant recipients (KTR) often have reduced muscle mass and strength. We aimed to investigate the potential relationship of muscle mass and strength with physical health-related quality of life (HRQoL) in KTR. MethodsData from the TransplantLines Biobank and Cohort Studies were used. Muscle mass was assessed with appendicular skeletal muscle mass index (ASMI) and 24-hour urinary creatinine excretion rate index (CERI). Muscles strength was assessed by handgrip strength index (HGSI). HRQoL was measured using Short Form 36 physical component score (PCS). ResultsWe included 751 KTR (61% male, mean age 56±13y, median 3y post-transplant). Ordinary least squares regression analyses demonstrated that lower ASMI, CERI and HGSI were all non-linearly associated with lower PCS, independent of potential confounders and each other. Below median values, ASMI, CERI and HGSI were each associated with PCS, whereas above median values, associations were less pronounced. Compared to the 50th percentile, a decrease to the 10th percentile was associated with a decrease in PCS of 4.8% for ASMI (P=0.011), of 5.1% for CERI (P=0.008) and 13.2% for HGSI (P<0.001), whereas an increase to the 90th percentile was associated with an increase in PCS of only 0.7% for ASMI (P=0.54), of 3.6% for CERI (P=0.05) and -0.4% for HGSI (P=0.73). ConclusionsLow muscle mass and strength are potentially modifiable risk factors for impaired physical HRQoL in KTR. The non-linear associations suggest that KTR with low muscle mass or strength may particularly benefit from (p)rehabilitation interventions to improve HRQoL.

Elevated Cystatin C Predicts Higher Mortality in Chronic Heart Failure Independently of Renal Function.

Cystatin C (CysC) is a known prognostic marker in cardiovascular diseases and its role in acute heart failure (HF) has been documented. We prospectively recruited HF patients followed in a HF clinic. Inclusion criteria: HF diagnosed ≥6 months, optimized evidence-based therapy, and ejection fraction <40% (Heart Failure with reduced ejection fraction). Exclusion criteria: renal replacement therapy and hospitalizations or therapeutic adjustments in the previous 2 months. A venous blood sample and 24-hour urine were collected. Follow-up: 5 years; endpoint: all-cause mortality. CysC was measured and creatinine clearance (CrCl) was calculated using 24-hour urine creatinine excretion. A Receiver operating characteristic curve was used to assess association of CysC with 5-year mortality. The prognostic role of CysC was determined using Cox-regression analysis. The multivariate model included CrCl (24-hour urine). We evaluated 215 chronic stable Heart Failure with reduced ejection fraction patients. Mean age was 68 years, 72.1% were male. Median CysC = 1.15 mg/L, creatinine = 1.20 mg/dL, and CrCl = 63.6 mL/min. During follow-up, 103 (47.9%) patients died. The area under the curve for CysC in predicting mortality was 0.77 (0.70-0.83). Best cut-off value for death prediction = 1.00 mg/L with a sensitivity = 83.5%, specificity = 56.2%, positive predictive value = 63.7%, and negative predictive value = 78.7%. Multivariate-adjusted (age-, B-type natriuretic peptide-, evidence-based therapy, New York Heart Association class, and CrCl) 5-year mortality Hazard ratio = 2.40 (95% Confidence interval, 1.25-4.61), P value = 0.008 when CysC ≥1.00 mg/L. Patients with CysC <1.00 mg/L have almost 80% probability of being alive at 5 years; If CysC ≥1.00 mg/L, there is almost 2.5-fold higher death risk independently of B-type natriuretic peptide and CrCl.

618-P: Development of a New Index Based on 24-Hour Urinary Creatinine to Predict Improvement of Lumbar Spine BMD after One Year of Zoledronic Acid Treatment for Osteoporosis

618-P: Development of a New Index Based on 24-Hour Urinary Creatinine to Predict Improvement of Lumbar Spine BMD after One Year of Zoledronic Acid Treatment for Osteoporosis

Predictive Modeling of Urinary Stone Composition Using Machine Learning and Clinical Data: Implications for Treatment Strategies and Pathophysiological Insights.

Purpose: Preventative strategies and surgical treatments for urolithiasis depend on stone composition. However, stone composition is often unknown until the stone is passed or surgically managed. Given that stone composition likely reflects the physiological parameters during its formation, we used clinical data from stone formers to predict stone composition. Materials and Methods: Data on stone composition, 24-hour urine, serum biochemistry, patient demographics, and medical history were prospectively collected from 777 kidney stone patients. Data were used to train gradient boosted machine and logistic regression models to distinguish calcium vs noncalcium, calcium oxalate monohydrate vs dihydrate, and calcium oxalate vs calcium phosphate vs uric acid stone types. Model performance was evaluated using the kappa score, and the influence of each predictor variable was assessed. Results: The calcium vs noncalcium model differentiated stone types with a kappa of 0.5231. The most influential predictors were 24-hour urine calcium, blood urate, and phosphate. The calcium oxalate monohydrate vs dihydrate model is the first of its kind and could discriminate stone types with a kappa of 0.2042. The key predictors were 24-hour urine urea, calcium, and oxalate. The multiclass model had a kappa of 0.3023 and the top predictors were age and 24-hour urine calcium and creatinine. Conclusions: Clinical data can be leveraged with machine learning algorithms to predict stone composition, which may help urologists determine stone type and guide their management plan before stone treatment. Investigating the most influential predictors of each classifier may improve the understanding of key clinical features of urolithiasis and shed light on pathophysiology.

Associations of fat and muscle mass indices with incident atrial fibrillation: data of PREVEND

Abstract Background Whether the association between body mass and atrial fibrillation (AF) risk is driven by fat mass or muscle mass remains unclear. Objective To examine the association of relative fat mass (RFM, a novel marker of whole-body fat percentage) and 24-hour urinary creatinine excretion (a marker of total muscle mass) with incident AF. Participants: We included 8120 community-dwelling adults from the PREVEND cohort without prevalent AF. Results The mean age of the population was 49.8±12.6 years and 50.0% (n=4060) were women. The mean RFM was 30.2±7.4 % and the mean creatinine excretion was 12.3±3.5 mmol/24h. During a mean follow-up period of 9.7±2.4 years, 261 AF events (3.2%) occurred. We included RFM, creatinine excretion, age, sex, height, heart rate, hypertension and cardiovascular disease history in a multivariable Cox regression model. The association between RFM and AF risk was linear, and the hazard ratio per 1 SD increase in RFM was 1.40; 95%CI: 1.17-1.66 (P&amp;lt;0.001). The association between creatinine excretion and AF risk was non-linear (P-value quadratic trend=0.006): compared with individuals in tertile 2 of creatinine excretion, those in tertile 1 had a HR of 1.70; 95%CI: 1.21-2.29 (P=0.002) and those in tertile 3 also had a HR of 1.74; 95%CI: 1.22-2.47 (P=0.002). Conclusion In the general population, both fat mass and muscle mass are associated with incident AF. While obesity should be considered as a major risk factor for AF, increased AF risk in individuals with low and high muscle mass warrants further investigation.

#1483 Creatinine excretion can serve more than a marker of kidney function in patients in the late postoperative period of bariatric surgery

Abstract Background and Aims Bariatric and metabolic surgery is the treatment of choice for severe obesity aiming to improve quality of life and control comorbidities, including chronic kidney disease (CKD). Careful monitoring of metabolic components, including markers of kidney function, are needed in the late postoperative period. The 24-hour urinary creatinine excretion rate (CER) and the Creatinine-Height Index (CHI) are accepted as non-invasive methods to evaluate kidney function, which are associated with skeletal muscle mass. However, it is not known whether these markers are also associated with muscle function among patients who underwent bariatric surgery after a period of massive weight loss. Therefore, the present study aims to investigate the association between kidney function markers with muscle function in individuals in the late postoperative period of bariatric surgery . Method This is a cross-sectional study, including women who underwent bariatric surgery for more than 18 months, when weight loss trajectory tends to stabilize. Age, date of surgery, self-reported preoperative weight, current body mass index (BMI) were collected to determine nutritional status. Patients with a BMI above 25 kg/m² were considered to have excessive body weight. Total weight loss (%TWL) and excess weight loss (%EWL) after surgery were also calculated. Patients underwent a blood test to assess serum creatinine (mg/dL) and collected 24-hour urine to estimate CER and CHI. Urinary collection was checked for adequate collection and patients with inadequate collections were excluded from the analysis. Muscle function comprised the assessment of muscle strength by handgrip strength [(HGS) JAMAR®, USA], 30-second chair stand test (30-CST) and, physical performance by timed-up and go test (TUG). Pearson's correlation was performed to test the correlation between the variables of interest and independent T-test to compare differences in creatinine markers and muscle function in the groups of patients with normal and excessive body weight. Results We analyzed 89 women (mean age 39.4 ± 8.0 years; BMI 28.6 ± 4.7 kg/m²). Bariatric surgery were at a median time of 3.9 (1.7 – 6.6) years post-operative; %TWL and %EWL were 38.0 ± 8.5% and 79.1 ± 20.2 %, respectively. Mean serum creatinine, CER and CHI were 0.67 ± 0.12 mg/dL; 5.7 ± 2.7 mmol/L; and 120.1 ± 22.5%, respectively. Significantly higher muscle strength was found between patients with excessive body weight (n = 69) compared to those with normal body weight (n = 20) for the HGS (29.2 ± 5.1 vs. 26.5 ± 5.8 kgf, p = 0.037) but not for the 30-CST (15.3 ± 4.0 vs. 14.4 ± 3.7 repetitions, p = 0.181) or performance by TUG test (6.1 ± 0.90 vs 6.1 ± 0.95 seconds, p = 0.450). Considering the total sample, HGS was significantly correlated with CHI (r2 0.238, p = 0.025, ) but not with serum creatinine or CER (r2 0.180, p = 0.093; r2 -0.047, p = 0.662, respectively). No significant correlations were found between the creatinine variables with 30-CST and TUG tests, except among patients with excessive body weight, where CER showed a significant correlation with the 30-CST test (r2 0.257, p = 0.034). Conclusion In addition to the already known effects on muscle mass, creatinine variables were correlated with muscle strength and, among those who still present excessive body weight after bariatric surgery, also with muscle functionality. Further studies may clarify mechanisms involved in physical function and creatinine excretion after a massive weight loss promoted by bariatric surgery. Determination of creatinine excretion could be useful in addition to the imaging technique arsenal available for metabolic assessment in studies with this population set.

#1462 Muscle mass, muscle strength, and health-related quality of life in kidney transplant recipients results of the TransplantLines Biobank &amp; cohort study

Abstract Background and Aims Muscles play a vital role in nearly every aspect of daily living, and kidney transplant recipients (KTR) often experience reduced muscle mass and strength, potentially contributing to their diminished health-related quality of life (HRQoL). We aimed to investigate the potential relationship of muscle mass and muscle strength with physical HRQoL in KTR. Method Data of stable KTR (≥1 year after transplantation) enrolled in the TransplantLines Biobank and Cohort Studies were used. Muscle mass was assessed using both appendicular skeletal muscle mass (via bioimpedance analysis) indexed to height squared (ASMI) and 24-hour urinary creatinine excretion rate indexed to height squared (CERI). Muscle strength was assessed using handgrip strength indexed to height squared (HGSI). HRQoL was assessed using the physical component score derived from the Short Form 36 questionnaire. Results A total of 751 KTR (61% male, mean age 56 ± 13 years) at a median of 3 years after transplantation were included. Mean ASMI was 7.5 ± 1.2 kg/m2, mean CERI was 4.1 ± 1.1 mmol/24 h/m2 and mean HGSI was 12.4 ± 3.4 kg/m2. The mean physical HRQoL score was 70 ± 21. Lower ASMI, CERI and HGSI were all associated with lower physical HRQoL, independent of potential confounders. Both associations were best characterized by a significant non-linear relationship (see Figure). Below median values, ASMI, CERI and HGSI were each associated with physical HRQoL, whereas above median values, associations were far less pronounced. When associations of ASMI, CERI and HSGI were adjusted for each other, associations of below median values of ASMI and CERI with physical HRQoL materially weakened, while those of HGSI remained strongly associated. Compared to the 50th percentile, a decrease to the 10th percentile was associated with a decrease in physical HRQoL of 6.0% for ASMI (P = 0.006), of 5.1% for CERI (P = 0.006) and 13.2% for HGSI (P &amp;lt; 0.001), whereas an increase to the 90th percentile was associated with an increase in physical HRQoL of only 1.3% for ASMI (P = 0.22), of 3.6% for CERI (P = 0.05) and −0.4% for HGSI (P = 0.73). Conclusion Our findings suggest that low muscle mass and muscle strength are potentially modifiable risk factors for impaired physical HRQoL. Both muscle mass and muscle strength were complementarily associated with HRQoL. However, muscle strength was most strongly associated with physical HRQoL. The non-linear nature of the associations implies that KTR with low muscle mass or strength may particularly benefit from (p)rehabilitation interventions to improve HRQoL.

Accuracy of eGFR Equation for Predicting Glomeruloar Filtration Rate in Potential Living Kidney Donor

This Descriptive Cross-Sectional Study, involving 201 patients, conducted at Sindh Institute of Urology and Transplantation (SIUT) Karachi, Pakistan after approval from institute research board. The estimated Glomerular Filtration Rate (eGFR) was calculated using the appropriate equation. Participants were instructed to collect their urine over a 24-hour period in a container devoid of any additives or preservatives. The collected urine specimens were subsequently sent to the institutional laboratory for analysis, with GFR determined based on 24-hour urine creatinine clearance to ensure accuracy. All data collected during the study period were meticulously entered into a predefined proforma, which was then electronically stored and utilized for research purposes.&#x0D; Results: Mean ± SD of age was 33.30±9.12 years. Out of 201 patients, 124 (61.7%) were male while 77 (38.3%) were female. In distribution of accuracy of eGFR by CKD-EPI equation, accuracy of (Cr-Cys) equation was noted as 60 (29.9%), (Cys) as 47 (23.4%) while accuracy of CKD- EPI (PK) equation was documented as 96 (47.8%).&#x0D; Conclusion: It is to be concluded that accuracy of CKD-EPI is closer to 24 -h urinary creatinine clearance in the calculation of eGFR. However, none of the eGFR formulas can be used in renal transplant donors because of their low accuracy, and 24-h urine creatinine clearance should be used for evaluation of the GFR in this population.

Pre-donation assessment of cystatin C to improve prediction of pre- and post-donation GFR in potential living kidney donors.

Accurate estimation of glomerular filtration rate (GFR) is crucial in living kidney donation. While most estimated GFR (eGFR) equations are based on plasma creatinine, its levels are strongly influenced by muscle mass. Application of cystatin C (cysC)-based estimates before donation may improve both estimation of current GFR and prediction of post-donation GFR. We assessed the performance of Chronic Kidney Disease Epidemiology Collaboration equations based on creatinine (eGFRcreat-2009, eGFRcreat-2021), cysC (eGFRCysC-2012) or both (eGFRcombined-2012, eGFRcombined-2021) for estimating pre- and post-donation (mGFR) GFR in 486 living kidney donors. We subsequently focused on a subgroup of individuals with high/low muscle mass (25% highest/lowest 24-hour urinary creatinine excretion, sex stratified and height indexed). Pre-donation eGFRcombined-2012 and eGFRcombined-2021 showed the strongest associations with pre- and post-donation mGFR. Pre-donation eGFRcombined-2021 was most accurate for estimating both pre-donation (bias 0.01±11.9ml/min/1.73m2) and post-donation mGFR (bias 1.3±8.5ml/min/1.73m2). In donors with high/low muscle mass, cysC-based equations (with or without creatinine) performed better compared with equations based on only creatinine. Combined eGFR equations yielded a better estimate of pre- and post-donation mGFR compared with estimates based on creatinine or cysC only. The added value of cysC seems particularly pronounced in donors with high or low muscle mass.

Change Over Time in Pre–End-Stage Renal Disease 24-Hour Urine Creatinine as Muscle Mass Surrogate and Post–End-Stage Renal Disease Mortality

Loss of muscle mass and sarcopenia are common in chronic kidney disease (CKD) and end-stage renal disease (ESRD), and sarcopenia can worsen insidiously in patients with advancing CKD. The temporal dynamics of sarcopenia in patients with progressive loss of kidney function, and its association with future outcomes, is unclear. In a contemporary national cohort of incident ESRD US veterans, we selected 661 patients who had at least 2 24-hour urine creatinine (24hrUC) measurements, a surrogate of muscle mass, performed during the 3-year prelude period prior to ESRD transition. We estimated 24hrUC slopes in mixed effects models. To assess the temporal dynamics of pre-ESRD changes in 24hrUC and its association with changing eGFR, we separately fitted in mixed effects models a penalized spline regression of 24hrUC on time and on eGFR. We examined the association of 24hrUC slopes with postdialysis all-cause mortality using Cox models adjusted for confounders. The mean slope of 24hrUC versus time was -78mg/year (95% confidence interval: -102 to -54), with a steeper decline noted in the last year prior to ESRD. More severe decreases in 24hrUC were associated with higher all-cause mortality: a 100mg/year decrease in 24hrUC was associated with a multivariable adjusted death hazard ratio of 1.41 (95% confidence interval: 1.00-1.98, P=.05). Patients with advanced CKD lose a substantial proportion of their muscle mass each year during pre-ESRD prelude. Loss of muscle mass accelerates near ESRD transition, and more loss of muscle mass is associated with higher mortality after ESRD transition.

Preventing Pneumonia in High-risk Patients After Esophageal Cancer Surgery: Mini-tracheostomy and Tazobactam/Piperacillin.

We evaluated the usefulness of prophylactic mini-tracheostomy (PMT) and perioperative administration of tazobactam/piperacillin (TAZ/PIPC) in high-risk patients after esophagectomy. We retrospectively studied 89 consecutive high-risk patients who underwent esophagectomy for esophageal cancer between January 2013 and December 2021. We defined patients with two or more of the following factors as high risk: age ≥70 years, performance status ≥1, respiratory dysfunction, liver dysfunction, cardiac dysfunction, renal dysfunction, diabetes mellitus, albumin <3.5 g/dl, and Brinkman index >600. Standard management was administered to the first 50 patients (standard group). PMT and TAZ/PIPC were administered to the next 39 patients (combination group). Patient characteristics and short-term outcomes were compared before and after propensity-score matching. Before propensity-score matching, 24-hour urine creatinine clearance, retrosternal route, 3-field lymph node dissection, and open abdominal approach were more common, postoperative pneumonia (13% vs. 36%, p=0.045) and complications of grade ≥3b (2.6% vs. 22%, p=0.01) were less frequent, and the postoperative hospital stay was shorter (median: 23 vs. 28 days, p=0.022) in the combination group than in the standard group. In propensity-score matching, patient characteristics, except for 24-h creatinine clearance and reconstructive route, were matched for 23 paired patients. Postoperative pneumonia (8.7% vs. 39%, p=0.035) and complications of grade ≥3b (0% vs. 26%, p=0.022) were less frequent and postoperative hospital stay was shorter (median: 22 vs. 25 days, p=0.021) in the combination group than in the standard group. PMT with TAZ/PIPC can potentially prevent postoperative pneumonia in high-risk patients after esophagectomy.

SAT217 Chronic Asymptomatic Hypoparathyroidism Due To Two Separate Single Nucleotide Heterozygous Mutations In The CaSR Gene

Abstract Disclosure: M. Antony: None. S. Gundlapally: None. S. Storm: None. P. Russell: None. V. Verma: None. R. Kant: None. Introduction: The most common cause for acquired hypoparathyroidism is either post-surgical or autoimmune destruction of the parathyroid glands. The clinical presentation can range from an asymptomatic state to severe life-threatening symptoms that require intensive therapeutic management with intravenous and/or oral calcium, calcitriol and in some cases, recombinant parathyroid hormone therapy. Hypoparathyroidism secondary to CASR (calcium sensing gene receptor) gene mutation is an uncommon etiology that can also have a varied clinical presentation as above. Clinical Case: A 60-year-old Caucasian male with no significant past medical history was found to have chronic hypocalcemia. He denied experiencing symptoms such as numbness, tingling or cramping sensation around face, lips, or upper extremities. He denied a history of movement disorder or dental problems. He denied a history of neck surgeries or neck radiation exposure. He denied a family history of calcium disorders. He was on calcium carbonate/Vitamin D3 600 mg/400 I.U once daily. The first documented low corrected serum calcium was 6.9 mg/dl (8.6-10.0 mg/dl) in November of 2017. Since then, there have been multiple low corrected serum calcium levels ranging between 7 to 7.6 mg/dl. Patient underwent endocrinology work-up after withholding the above calcium/Vitamin D3 supplementation and it revealed a low corrected serum calcium of 7.6 mg/dl with an inappropriately normal serum PTH level of 37 pg/ml (15-65 pg/ml), normal vitamin D level of 45.1 ng/ml (&amp;gt; 30.0 ng/ml), normal serum phosphorus 3.8 mg/dl (2.5-4.5 mg/dl), and normal serum magnesium 1.8 mg/dl (1.6-2.6 mg/dl). The 24-hour urine calcium was 93 mg/24 hour with a corresponding 24-hour urine creatinine of 1836 mg (1040-2350 mg/24hour) and urine volume of 1625 ml. CASR gene analysis revealed two separate single nucleotide heterozygous mutations. The first mutation was at Exon 4/7, nucleotide position was c.614G&amp;gt;A and Amino Acid position was p.Arg205His. The second mutation was at Exon 7/7, nucleotide position was c.2546T&amp;gt;C and Amino Acid Position is p.lle849Thr. Due to lack of specific symptoms, patient was not initiated on specific therapies such as calcitriol or Natpara (recombinant PTH) and was advised to continue taking the daily calcium/vitamin D3 supplementation. He is being currently monitored every 4 to 6 months to assess for any clinical symptoms along with pertinent laboratory work-up. Conclusion: Hypoparathyroidism due to CASR gene mutation has a varied clinical presentation. One-third of cases do not develop any clinical symptoms, such as our patient and hence do not warrant any specific treatment other than periodic clinical and biochemical assessment. Presentation: Saturday, June 17, 2023

Analysis of Clinical Characteristics of Patients with Different Types of Primary Hyperuricemia

Objective: This paper aims to study the clinical characteristics of patients with different types of primary hyperuricemia (HUA). Methods: Using a retrospective research method, 200 patients with primary HUA in the hospital from June 2020 to January 2023 were selected as the research objects. Patients were grouped according to the detection results of 24-hour urinary uric acid excretion (UUE) and fractional excretion of uric acid (FEUA) (renal insufficiency type, renal overload type, mixed type, and other types). The general information of patients in the four groups (gender, age, body mass index, living habits, etc.), underlying diseases (hypertension, diabetes), blood test results [uric acid (UA), creatinine (Cre)], urine test results (24-hour urine UA, 24-hour urine Cre) were summarized and the differences between the groups were analyzed. Results: The 200 cases of HUA patients were divided into 54.00% with renal insufficiency type, 38.50% with mixed type, 6.00% with renal overload type, and 1.50% with other types. The age of patients with mixed HUA was younger than that of patients with other types, renal overload type, and renal insufficiency type, and the difference was statistically significant (P &lt; 0.05). The UA level of patients with other types of HUA was lower than that of patients with mixed type HUA, and there was statistical significance (P &lt; 0.05). The Cre level of patients with mixed type HUA was lower than that of patients with renal insufficiency type and renal overload type, and the difference was statistically significant (P &lt; 0.05). The 24-hour urinary UA level in patients with renal insufficiency type HUA was lower than that in patients with renal overload type and mixed type HUA, and the difference was statistically significant (P &lt; 0.05). The 24-hour urinary Cre level of patients with other types of HUA was lower than that of patients with renal overload type and mixed HUA, the difference was statistically significant (P &lt; 0.05). The estimated glomerular filtration rate (eGFR) level of patients with other types of HUA was lower than that of patients with mixed type HUA, and the difference was statistically significant (P &lt; 0.05). There was no significant difference in the proportions of hypertension, diabetes, coronary heart disease, and urinary calculi among patients with renal insufficiency type, renal overload type, mixed type, and other types of HUA (P &gt; 0.05). Conclusion: The primary HUA patients are mainly of renal insufficiency type, followed by mixed type. There are significant differences in the clinical characteristics of patients with different types of HUA. Among them, patients with other types of HUA are the oldest and have the lowest uric acid levels. Patients with mixed HUA had the best renal function but the highest 24-hour urine creatinine level. This study can be used as a basis for rational selection of urate-lowering drugs for different HUA patients.

Screening of Proteinuria by Urinary Specific Gravity in Nephrotic Syndrome

Background: Nephrotic syndrome is the commonest glomerular disease in children and is often characterized by multiple relapses. Twenty-four hours urinary protein estimation is the accepted method used in the quantification of proteinuria, but it’s a time-consuming, inconvenient and cumbersome and difficult in very young children. This study emphasized screening of proteinuria by urinary specific gravity in nephrotic syndrome. Material &amp; Methods: This cross-sectional study was conducted in the Department of Pediatric Nephrology (NIKDU), Dhaka, Bangladesh from October 2019 to June 2021. A total of 153 patients with nephrotic syndrome were enrolled as the study subjects after taking written consent. Urine samples were collected for both 24 hours and spot for estimation of urinary protein, urinary creatinine (Ucr) and specific gravity by dipstick method. Spot and 24-hour urinary protein creatinine ratio (PCR) were also estimated. From urinary specific gravity, estimated urinary creatinine (estUcr) and estimated urinary protein creatinine ratio (est PCR) were measured. A descriptive method was used and data were processed by using SPSS version 22.0. Results: Among 153 study subjects, the maximum (44.4%) were from the 2-5 years age group followed by 58 (37.9%) from 5-10 years and 27 (17.6%) from &gt;10 years age groups. Boys (61.4%) were more predominant than girls (38.6%) in number. Spot and 24-hour urinary specific gravity have a significant positive correlation with urinary creatinine. Urinary creatinine was estimated by using the equation (Ucr = 1.25×1000 Usg – 1.24×1000). Both spot and 24-hour estimated urinary PCR (est PCR) measured by using urinary specific gravity have a significant positive correlation with corresponding urinary PCR. Conclusion: This study concluded that spot urinary specific gravity has a significant positive correlation with spot urinary protein and spot urinary creatinine. PCR can be estimated from dipstick urinary specific gravity instead of urinary creatinine in the cumbersome laboratory. Therefore, the study may establish an easy, rapid, inexpensive and alternative method for the detection of proteinuria in nephrotic syndrome so that it will help for early detection of relapse and prevent further complications related to nephrotic syndrome.

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

ObjectiveThere are several equations for estimating the glomerular filtration rate (GFR), and each method has its limitations. We compared various estimated GFR (eGFR) equations with 24 hours urine creatinine clearance...

Comparison of Three Glomerular Filtration Rate Estimating Equations with 24-Hour Urine Creatinine Clearance Measurement in Potential Living Kidney Donors.

The accuracy of the measurement of renal function in potential living kidney donors (PLKD) is essential. The direct measurement of glomerular filtration rate (mGFR) has been considered the "gold standard." The estimated GFR (eGFR) with 24-hour urinary creatinine clearance (CrCl) is frequently used because of its availability. We aim to evaluate the correlation and agreement of eGFR using serum-based creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI) and the eGFR based on 24-hour urinary CrCl to evaluate kidney function in PLKD. We evaluated the kidney function in 799 PLKD using 24-hour urinary CrCl method and compared the correlation and agreement with the eGFR based on creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI). We calculated the mean bias (difference), precision (SD of this difference), accuracy, and performed Bland-Altman plots. A total of 799 PLKD were analyzed. The age of the PLKD ranged from 18 to 73 years. Weak to mild correlation was observed between 24-hour urinary CrCl and all formulas (ranged from 0.31 to 0.49). The three equations underestimated the GFR. Using the Bland-Altman graphic, we observed that the CKD-EPI was the least scattered and most precise; however, mean bias and the interval range (limits of agreement) of all formulas were too big to assume equivalence between 24-hour urinary CrCl method and eGFR based on creatinine. Results of mean bias were similar when comparing the three equations in patients with CrCl GFR <60. However, the accuracy of all formulas was better for the female group and the youngest individuals (≤40 years old). In this PLKD cohort, of all the three equations, the CKD-EPI was the least scattered and most precise. However, the correlation and the level of agreement between the three equations and 24-hour urinary CrCl were too low to assume the equivalence.

#5565 USEFULNESS OF URINARY BIOCHEMISTRY IN THE FOLLOW-UP OF PATIENTS WITH CHRONIC KIDNEY DISEASE STAGES 3B-5NOD

Abstract Background and Aims Ion and protein determinations in a simple urine sample are simple and inexpensive laboratory tests that reflect well ion balance and proteinuria. However, they are underused. Evidence of their usefulness in estimating 24-hour urine biochemistry in patients with chronic kidney disease (CKD) would allow widespread use of these tests and would help to optimize therapies. It would also avoid 24-hour urine collections. To evaluate In CKD stages G3b-5noD the accuracy of equations that estimate, through simple urine sampling, creatinine, protein, and ions in 24-hour urines. Method Retrospective observational study in incident adult patients with CKD G3b-5noD from the nephrology outpatient clinic in a Madrid university hospital, with a follow-up of at least two years and with at least one simultaneous determination of biochemistry in a simple urine sample and in 24-hour urine. The 24-hour urine analyses were restricted to those that were estimated to be well collected because urinary creatinine was between 15–25 mg/kg in men and 10–20 mg/kg in women. Correlation, bias (mean differences between estimated and measured analyte), accuracy (percentage of samples estimated at 15–30 or 50% of the measured value - P15, P30, P50) and agreement by the Bland-Altman method were analyzed. CKD progression was defined by the mean annual and percentage decrease in eGFR and the renal event at follow-up as loss of more than 40% of eGFR or entry into renal replacement therapy or conservative-palliative renal treatment. Kawasaki, Tanaka and CKD-epi (Table 1) equations were used. Results The analyzed cohort was made up of 300 patients with a median follow-up of 72 (25) months. Mean eGFR was 32.8 (9.2) ml/min/1.73m2 and mean protein/creatinine ratio was 1,180 (1,740) mg/g. During follow-up 30.7% started renal replacement therapy or conservative and palliative treatment. Twenty-one patients (7%) died. The estimation of 24-hour urine creatinine by CKD-EPI equation showed excellent correlation and accuracy with measured urinary creatinine (r = 0.887; P30: 96.1% in 464 urines). Accuracy was maintained regardless of age and CKD stage. Formulas that, using single urine samples, estimate 24-hour urine elimination of Na and K correlated well with 24-hour urine measurements, but with high dispersion, especially with Na. For Na, the Tanaka and CKD-EPI formulas had the highest performance (r = 0.540; 0.532; P30: 52.6; 54.5%; bias: -14.4; -16.1 mmol, Tanaka and CKD-EPI respectively for 464 urines). These values make them useful for population studies but not for individualized analysis. For K, the Kawasaki and CKD-EPI formulas were the most suitable (r = 0.712; 0.612; P30 = 74.6; 72.4%; bias: 4.2; 5.5 mmol; Kawasaki and CKD-EPI respectively for 464 urines). These results make them useful for both population-based studies and individualized analyses. Patients with Nao &amp;lt; 87 mmol/day (salt-poor diet) estimated by CKD-EPI, Kawasaki or Tanaka and/or Na/K ratio &amp;lt; 2 directly measured had less eGFR loss at follow-up and fewer renal events. Urinary K elimination measured or estimated did not influence renal prognosis. Proteinuria measured in 24-hour urine correlated much better with proteinuria estimated by CKD-EPI in a single urine sample than with the protein/creatinine ratio (r: 0.900 vs. 0.801; mean bias: 92.2 vs. 486 mg; P30: 72.0 vs. 42.7%; CKD-EPI vs. Proto/Cro in 464 24-hour urine samples). Conclusion Urinary biochemistry in a single urine sample in patients with advanced CKD (stages G3b-5noD) is a useful tool for estimating 24-hour urine biochemistry and to identify scenarios of increased progression of renal disease.

Estimation of 24-hour urinary creatinine excretion from patient variables: A novel approach to identify patients with low muscle mass and malnutrition and relationship to outcomes.

Low muscle mass has been correlated with adverse outcomes in patients who are critically ill. Methods to identify low muscularity such as computed tomography scans or bioelectrical impedance analyses are impractical for admission screening. Urinary creatinine excretion (UCE) and creatinine height index (CHI) are associated with muscularity and outcomes but require a 24-h urine collection. The estimation of UCE from patient variables avoids the need for a 24-h urine collection and may be clinically useful. Variables of age, height, weight, sex, plasma creatinine, blood urea nitrogen (BUN), glucose, sodium, potassium, chloride, and carbon dioxide from a deidentified data set of 967 patients who had UCE measured were used to develop models to predict UCE. The model identified with the best predictive ability was validated and then retrospectively applied to a separate sample of 120 veterans who were critically ill to examine if UCE and CHI predicted malnutrition or were associated with outcomes. A model was identified that included variables of plasma creatinine, BUN, age, and weight and was found to be highly correlated, moderately predictive of UCE, and statistically significant. Patients with model-estimated CHI 60% had significantly lower body weight, body mass index, plasma creatinine, and sera albumin and prealbumin levels; were 8.0 times more likely to be diagnosed with malnutrition; and were 2.6 times more likely to be readmitted in 6 months. A model that predicts UCE offers a novel method to identify patients with low muscularity and malnutrition on admission without the use of invasive tests.

WED-388 - 24-Hour urinary creatinine excretion (UCE) a marker of muscle mass is associated with mortality in critically ill patients with cirrhosis

WED-388 - 24-Hour urinary creatinine excretion (UCE) a marker of muscle mass is associated with mortality in critically ill patients with cirrhosis