Performance of the European Kidney Function Consortium (EKFC) creatinine-based equation in United States cohorts.

Estimating glomerular filtration rate (GFR) is important in daily practice to assess kidney function and adapting the best clinical care of patients with and without chronic kidney disease. The new creatinine-based European Kidney Function Consortium (EKFC) equation is used to estimate GFR. This equation was developed and validated mainly in European individuals and based on a rescaled creatinine, with the rescaling factor (Q-value) defined as the median normal value of serum creatinine in a given population. The validation was limited in Non-Black Americans and absent in Black Americans. Here, our cross-sectional analysis included 12,854 participants from nine studies encompassing large numbers of both non-Black and Black Americans with measured GFR by clearance of an exogenous marker (reference method), serum creatinine, age, sex, and self-reported race available. Two strategies were considered with population-specific Q-values in Black and non-Black men and women (EKFCPS) or a race-free Q-value (EKFCRF). In the whole population, only the EKFCPS equation showed no statistical median bias (0.14, 95% confidence interval [-0.07; 0.35] mL/min/1.73m2), and the bias for the EKFCRF (0.74, [0.51; 0.94] mL/min/1.73m2) was closer to zero than that for the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI2021) equation (1.22, [0.99; 1.47]) mL/min/1.73m2]. The percentage of estimated GFR within 30% of measured GFR was similar for CKD-EPI2021 (79.2% [78.5%; 79.9%]) and EKFCRF (80.1% [79.4%; 80.7%]), but improved for the EKFCPS equation (81.1% [80.5%; 81.8%]). Thus, our EKFC equations can be used to estimate GFR in the United States incorporating either self-reported race or unknown race at the patient's discretion per hospital registration records.

Difference Between Estimated GFR Based on Cystatin C Versus Creatinine and Incident Atrial Fibrillation: A Cohort Study of the UK Biobank.

RATIONALE & OBJECTIVE: The difference between cystatin C-based and creatinine-based estimated glomerular filtration rate (eGFRdiff) has been suggested to reflect factors distinct from kidney function that are associated with cardiovascular risk. However, the association between eGFRdiff and atrial fibrillation (AF) risk has not been extensively evaluated. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Using data from the UK Biobank, this study included 363,494 participants with measured serum creatinine and cystatin C levels and without a prior diagnosis of AF or a history of related procedures. EXPOSURE: Estimated GFRdiff, calculated as cystatin C-based eGFR minus creatinine-based eGFR. Estimated GFRdiff was also categorized as negative (<-15mL/min/1.73m2), midrange (-15 to 15mL/min/1.73m2), or positive (≥15mL/min/1.73m2). OUTCOME: Incident AF. ANALYTICAL APPROACH: Subdistribution hazard models were fit, treating death that occurred before development of AF as a competing event. RESULTS: During the median follow-up period of 11.7 years, incident AF occurred in 18,994 (5.2%) participants. In the multivariable-adjusted model, participants with a negative eGFRdiff had a higher risk of incident AF (subdistribution HR [SHR], 1.25 [95% CI, 1.20-1.30]), whereas participants with a positive eGFRdiff had a lower risk of AF (SHR, 0.81 [95% CI, 0.77-0.87]) compared with those with a midrange eGFRdiff. When eGFRdiff was treated as a continuous variable in the adjusted model, every 10mL/min/1.73m2 higher eGFRdiff was associated with a 0.90-fold decrease in the risk of incident AF. LIMITATIONS: A single measurement of baseline serum creatinine and cystatin C levels. CONCLUSIONS: The difference between cystatin C- and creatinine-based eGFRs was associated with the risk of AF development. A higher eGFRdiff was associated with a lower risk of AF. These findings may have implications for the management of patients at risk of incident AF. PLAIN-LANGUAGE SUMMARY: The difference between cystatin C-based estimated glomerular filtration rate (eGFR) and creatinine-based eGFR has recently gained attention as a potential indicator of cardiovascular outcomes influenced by factors other than kidney function. This study investigated the association between the differences in 2 eGFRs (cystatin C-based eGFR minus creatinine-based eGFR) and incident atrial fibrillation (AF) among>340,000 participants from the UK Biobank Study. Compared with those with a near zero eGFR difference, participants with a negative eGFR difference had a higher risk of AF, while those with a positive eGFR difference had a lower risk. These findings suggest that measuring eGFR differences may help identify individuals at a higher risk of developing AF.

Tumour-associated antigens in systemic lupus erythematosus: association with clinical manifestations and serological indicators.

OBJECTIVES: To explore the relationship of tumour-associated antigens (TAAs) with the clinical manifestations and serological markers of SLE. METHODS: This was a retrospective study. Clinical data of SLE patients were extracted from the electronic medical records, including serum levels of TAAs such as alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen (CA) 19-9, CA125, CA15-3 and cytokeratin 19-fragments (CYFRA21-1). TAA positivity was defined as serum level exceeding the upper limit of the corresponding reference range. RESULTS: A total of 149 SLE patients (SLE group) and 149 age- and sex-matched healthy subjects (control group) were enrolled. Compared with healthy controls, the SLE group had higher positivity rates for CA19-9 and CYFRA21-1, and elevated serum levels of CA125, CA15-3 and CYFRA21-1. SLE patients with TAA positivity were older, had a higher prevalence of serous effusion, pericardial effusion, albuminuria and thrombocytopenia, and lower positivity rate for anti-dsDNA than patients without TAA positivity. The levels of serum creatinine (SCR), blood urea nitrogen, glutamic oxalate transaminase and 24-h urinary protein were also higher in SLE patients with TAA positivity, but platelet count and serum albumin levels were lower. On logistic regression, thrombocytopenia and SCR levels were identified as independent risk factors for TAA positivity. CA125 positivity rate and serum levels of CA125 were associated with SLE disease activity. CONCLUSION: The positivity rates and serum levels of some TAAs were elevated in SLE, and thrombocytopenia and SCR levels were independent risk factors for TAA positivity.

Microvascular changes following exposure to iodinated contrast media in vitro. A qualitative comparison to serum creatinine concentrations in post-cardiac catheterization patients.

INTRODUCTION: Contrast-associated acute kidney injury (CA-AKI) is characterized as a loss of renal function following radiological contrast media administration. While all contrast media induce variable changes in microvascular endothelial cells in vitro, only few studies report clinical significance of their findings. A comprehensive assessment of the effect of iodinated contrast media on the renal function in vitro and in vivo is essential. The aim of our study was to morphometrically quantify the effect of two different contrast media (Iobitridol and Iodixanol) on vascular endothelial capillaries in vitro and to analyze their effect on the renal function of patients who underwent cardiac catheterization including the intra-arterial administration of contrast media, by measuring serum creatinine concentration (SCr), a byproduct of muscle metabolism, primarily excreted by the kidneys. Our hypothesis suggests that conducting a qualitative comparison of both outcomes will enable identification of differences and similarities between in vitro and in vivo exposure. MATERIAL AND METHODS: In vitro, co-cultures of human dermal fibroblasts and human dermal microvascular endothelial cells forming capillary beds were exposed to a mixture of phosphate buffered saline and either Iobitridol, Iodixanol, or one of their supplements EDTA or Trometamol for 1.5 or 5 min. Negative control co-cultures were exposed exclusively to phosphate buffered saline. Co-cultures were either directly fixed or underwent a regeneration time of 1, 3 or 7 days. An artificial intelligence software was trained for detection of labeled endothelial capillaries (CD31) on light microscope images and measurements of morphometric parameters. In vivo, we retrospectively analyzed data from patients who underwent intra-arterial administration of contrast media and for whom SCr values were available pre- and post-contrast exposition (1, 3, and 7 days following procedure). Temporal development of SCr and incidence of CA-AKI were assessed. Both exposure types were qualitatively compared. RESULTS: In vitro, Iobitridol, Iodixanol and EDTA induced a strong decrease of two morphometric parameters after 3 days of regeneration. In vivo, a significant increase of SCr and incidence of CA-AKI was observed 3 days following procedure in the post-contrast media patients. No difference was observed between groups. DISCUSSION: Two of the morphometric parameters were inversely proportional to the SCr of the patients. If the endothelial damages observed in vitro occur in vivo, it may result in renal hypoxia, inducing a loss of kidney function clinically translated into an increase of SCr. Further development of our in vitro model could allow closer replication of the internal structure of a kidney and bridge the gap between in vitro studies and their clinical findings.

Association of serum uric acid to serum creatinine ratio with 1-year stroke outcomes in patients with acute ischemic stroke: A multicenter observational cohort study.

BACKGROUND AND PURPOSE: Considering the reliance of serum uric acid (SUA) levels on renal clearance function, its role in stroke outcomes remains controversial. This study investigated the association of renal function-normalized SUA (SUA to serum creatinine ratio, SUA/SCr), a novel renal function index, with the 1-year outcomes in patients with acute ischemic stroke (AIS). METHODS: This is a prospective, multicenter observational study. Renal function-normalized SUA levels were determined by calculating the ratio of SUA to SCr. One-year outcomes included stroke recurrence, all-cause mortality, and poor prognosis. Multivariable Cox regression analyses and restriction cubic splines for curve fitting were used to evaluate SUA/SCr's association with 1-year stroke outcomes. RESULTS: Among 2294 enrolled patients, after adjustment for potential confounders, multivariable Cox regression analyses showed that each one-unit increase in SUA/SCr corresponded to a 19% decrease in 1-year stroke recurrence in patients with AIS. SUA/SCr was analyzed as a continuous variable and categorized into quartiles (Q1-Q4). Compared with the Q1 reference group, Q2, Q3, and Q4 showed significantly lower 1-year stroke recurrence risks. The trend test indicated significant differences in the 1-year stroke recurrence trend from Q1 to Q4. In these patients, SUA/SCr did not show a significant association with poor prognosis or all-cause mortality. Curve fitting revealed SUA/SCr had a negative but nonlinear association with 1-year stroke recurrence. CONCLUSIONS: In patients with AIS, low SUA/SCr may be an independent risk factor for 1-year stroke recurrence. Changes in SUA/SCr had no significant impact on 1-year poor prognosis and all-cause mortality.

Lower serum uric acid to serum creatinine ratio as a predictor of poor functional outcome after mechanical thrombectomy in acute ischaemic stroke.

BACKGROUND AND PURPOSE: The ratio of serum uric acid (SUA) to serum creatinine (SCr), representing normalized SUA for renal function, is associated with functional outcome in acute ischaemic stroke (AIS) patients. However, its effect on AIS patients undergoing mechanical thrombectomy (MT) remains unknown. This study aimed to investigate the influence of the SUA/SCr ratio on clinical outcome in MT-treated AIS patients. METHODS: Acute ischaemic stroke patients who underwent MT were continuously enrolled from January 2018 to June 2023. Upon admission, SUA and SCr levels were recorded within the initial 24 h. Stroke severity was determined using the National Institutes of Health Stroke Scale (NIHSS) score. Clinical outcome included poor functional outcome (modified Rankin Scale score >2) at 90 days, symptomatic intracranial haemorrhage and death. RESULTS: Amongst 734 patients, 432 (58.8%) exhibited poor functional outcome at 90 days. The SUA/SCr ratio exhibited a negative correlation with NIHSS score (ρ = -0.095, p = 0.010). Univariate analysis revealed a significant association between SUA/SCr ratio and poor functional outcome. After adjusting for confounders, the SUA/SCr ratio remained an independent predictor of functional outcome (adjusted odds ratio 0.348, 95% confidence interval 0.282-0.428, p < 0.001). Receiver operating characteristic curve analysis highlighted the ability of the SUA/SCr ratio to predict functional outcome, with a cutoff value of 3.62 and an area under the curve of 0.757 (95% confidence interval 0.724-0.788, p < 0.001). CONCLUSION: The SUA/SCr ratio is correlated with stroke severity and may serve as a predictor of 90-day functional outcome in AIS patients undergoing MT.

Does Severity of Donor Acute Kidney Injury Influence Outcomes Following Kidney Transplantation?

INTRODUCTION: The study purpose was to review retrospectively our single-center experience transplanting kidneys from deceased donors (DD) with acute kidney injury (AKI) according to terminal serum creatinine (tSCr) level. METHODS: AKI kidneys were defined by a doubling of the DD's admission SCr and a tSCr ≥ 2.0 mg/dL. RESULTS: From 1/07 to 11/21, we transplanted 236 AKI DD kidneys, including 100 with a tSCr ≥ 3.0 mg/dL (high SCr AKI group, mean tSCr 4.2 mg/dL), and the remaining 136 from DDs with a tSCr of 2.0-2.99 mg/dL (lower SCr AKI group, mean tSCr 2.4 mg/dL). These two AKI groups were compared to 996 concurrent control patients receiving DD kidneys with a tSCr < 1.0 mg/dL. Mean follow-up was 69 months. Delayed graft function (DGF) rates were 51% versus 46% versus 29% (p < 0.0001), and 5-year patient and death-censored kidney graft survival rates were 96.8% versus 83.5% versus 82.2% (p = 0.002) and 86.7% versus 77.8% versus 78.8% (p = 0.18) in the high tSCr AKI versus lower tSCr AKI versus control groups, respectively. CONCLUSIONS: Despite a higher incidence of DGF, patients receiving kidneys from DDs with tSCr levels ≥3.0 mg/dL have acceptable medium-term outcomes compared to either AKI DDs with a lower tSCr or DDs with a tSCr < 1.0 mg/dL.

Evaluation of clinically relevant serum proteins as biomarkers for monitoring COVID-19 severity, and end-organ damage among hospitalized unvaccinated patients.

BACKGROUND: The extensive variability and conflicting information in Coronavirus Disease 2019 (COVID-19) patient data have made it difficult for the medical community to gain a comprehensive understanding and develop clear, reliable guidelines for managing COVID-19 cases. As the world uncovers the diverse side effects of the pandemic, the pursuit of knowledge about COVID-19 has become crucial. The present study aimed to evaluate some clinically relevant serum proteins, providing analysis of the obtained results to employ them in the diagnosis, prognosis, and disease monitoring among COVID-19 patients. METHODS: Samples were collected from 262 COVID-19 unvaccinated hospitalized patients. Measurement of certain serum proteins, namely C-reactive protein (CRP), ferritin, D-dimer, procalcitonin, interleukin-6 (IL-6), serum creatinine (SCr), alanine transaminase (ALT), aspartate transaminase (AST) was done using standard methods. Statistical analysis was performed on the obtained data and the results were correlated to the severity and prognosis. RESULTS: The calculated Mortality rate was found to be 30% with a higher percentage observed among females. The results showed elevation in serum CRP, ferritin, D-dimer, and procalcitonin in most of the patients, also some patients had elevated SCr, ALT, and AST levels indicating end-organ damage. The statistical analysis displayed a strong correlation between serum levels of CRP and ferritin, between D-dimer and ferritin, and between ferritin and procalcitonin. No significant difference was observed between male and female patients' serum levels of the tested serum proteins. A significant correlation between increased serum procalcitonin and mortality was observed. CONCLUSION: The levels of measured serum proteins were impacted by SARS-CoV-2 infection. Serum ferritin, CRP, D-dimer, and procalcitonin are good predicting tools for end-organ damage and acute kidney impairment in COVID-19. Procalcitonin is a strong indicator of severity and mortality in hospitalized COVID-19 patients.

Effects of aminophylline therapy on urine output and kidney function in children with acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication of children admitted to the paediatric intensive care unit. One key management modality of AKI is the use of diuretics to reduce fluid overload. Aminophylline, a drug that is well known for its use in the treatment of bronchial asthma, is also purported to have diuretic effects on the kidneys. This retrospective cohort study assesses the effect of aminophylline in critically ill children with AKI. METHODS: A retrospective chart review of children admitted to the paediatric intensive care unit of the Red Cross War Memorial Children's Hospital (RCWMCH) with AKI who received aminophylline (from 2012 to June 2018) was carried out. Data captured and analyzed included demographics, underlying disease conditions, medications, urine output, fluid balance, and kidney function. RESULTS: Data from thirty-four children were analyzed. Urine output increased from a median of 0.4 mls/kg/hr [IQR: 0.1, 1.1] at six hours prior to aminophylline administration to 0.6 mls/kg/hr [IQR: 0.2, 1.9] at six hours and 1.6 mls/kg/hr [IQR:0.2, 4.2] at twenty-four hours post aminophylline therapy. The median urine output significantly varied across the age groups over the 24-h time period post-aminophylline, with the most response in the neonates. There was no significant change in serum creatinine levels six hours post-aminophylline administration [109(IQR: 77, 227)-125.5(IQR: 82, 200) micromole/l] P-value = 0.135. However, there were significant age-related changes in creatinine levels at six hours post-aminophylline therapy. CONCLUSIONS: Aminophylline increases urine output in critically ill children with AKI. A higher resolution version of the Graphical abstract is available as Supplementary information.

Mother-child correlation of kidney function: data from the Yamanashi Adjunct Study of Japan Environment and Children's Study (JECS).

BACKGROUND: Individual variation in kidney function can be affected by both congenital and acquired factors, and kidney function in children is possibly correlated with that in their mothers. However, the mother-child correlation in kidney function remains directly unconfirmed. METHODS: We conducted a cross-sectional study of 655 healthy pairs of 7- or 8-year-old children and their mothers as an adjunct study of a nationwide epidemiological study (Japan Environment and Children's Study). RESULTS: Both serum creatinine level (all children, r = 0.324, p < 0.001; girls, r = 0.365, p < 0.001; boys, r = 0.278, p < 0.001) and estimated glomerular filtration rate (eGFR) (r = 0.274, p < 0.001; r = 0.352, p < 0.001; r = 0.195, p < 0.001, respectively) in children were weakly associated with their maternal values. In the single linear regression analyses, maternal values of serum creatinine and eGFR were significantly associated with the children's values. Moreover, several body composition values in children, such as weight-SDS, fat (%), and predicted muscle weight, were also significantly associated with kidney function values in children. In the multiple linear regression analysis for serum creatinine levels in children, in which weight-SDS and predicted muscle weight in children were selected as adjustment factors, maternal serum creatinine level showed a significant positive association (B = 0.214, p < 0.001 in the adjusted model). Moreover, in the multiple linear regression analysis for eGFR value in children, in which fat (%) and predicted muscle weight in children were selected as adjustment factors, maternal eGFR values showed a significant positive association (B = 0.319, p < 0.001). CONCLUSIONS: We directly confirmed mother-child correlations in both serum creatinine levels and eGFR values, particularly in girls. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

Estimated glomerular filtration rate: applicability of creatinine-based equations in African children.

BACKGROUND: The Schwartz equation is the most widely used serum creatinine (SCr)-based formula to estimate the glomerular filtration rate (GFR) in children of European descent, but whether this applies to African children is unclear. METHODS: In a cross-sectional study, 513 apparently healthy African children aged 6 to 16 years were randomly recruited in school area of Kinshasa, the Democratic Republic of Congo (DRC). SCr was measured using calibrated enzymatic method. SCr was normalized using Q-values designed for European descent children, due to the absence of Q-values for African children. Commonly used eGFR equations were applied in this population. RESULTS: Normalization of SCr using Q-values for European descent children was effective in this cohort. The majority of African children (93.4%) have normalized SCr (SCr/Q) values within the reference interval (0.67-1.33) of children of European descent. The bedside-Schwartz equation was associated with significant age and sex dependency. However, the FAS-Age formula showed no sex and age dependency. The new CKiDU25 equation did not show a significant sex dependency. The recently introduced EKFC and LMR18 equations also showed no age and sex dependency, although the distribution of eGFR-values was not symmetrical. On the other hand, the FAS-Height and the Schwartz-Lyon equations showed significant sex dependency but no age dependency. CONCLUSIONS: The reference interval for SCr designed for European descent children can be applied to African children. Of all the equations studied, FAS-Age performed best and is most suitable because no height measurements are required. Establishment of specific Q-values for the widespread Jaffe-measured creatinine in Africa can further broaden applicability.

Pharmacovigilance of nephrotoxic drugs in neonates: the Pottel method for acute kidney injury detection in ELBW neonates.

BACKGROUND: Extremely low birth weight (ELBW) neonates (birth weight ≤ 1000 g) are at high risk to develop drug-induced acute kidney injury (AKI). However, we lack a pragmatic detection tool to capture their time-dependent (patho)physiologic serum creatinine (Scr) patterns. Pottel et al. suggested rescaling Scr by dividing Scr with the mean Scr value of the age- and sex-specific reference population. We explored if this Pottel method can detect drug-related nephrotoxicity in ELBW neonates. METHODS: A previously reported dataset on Scr changes in ELBW neonates exposed to ibuprofen, amikacin, or vancomycin was updated to calculate Pottel scores for every available Scr value in the first 28 postnatal days. We hereby used previously published postnatal age-specific 50th centile values in an ELBW population. Linear mixed models were applied, analyzing Pottel scores as response variable and continuous time (day), drug exposure, and interaction thereof in the explanatory model. RESULTS: Serum creatinine (n = 3231) observations in 201 ELBW neonates were collected. A statistically significant rise of Pottel scores was observed with ibuprofen starting from postnatal day 4. In addition, a cumulative effect of treatment with mean Pottel scores on day 0 of 1.020 and on day 3 during treatment of 1.106 (95% CI 1.068-1.145, p < 0.001) was observed, corrected for effect of antibiotics. Antibiotic administrations showed a small but statistically significant difference up to postnatal day 5. CONCLUSIONS: As rescaled Scr biomarker, the Pottel method showed a clear association with ibuprofen-exposed ELBW neonates, suggesting its applicability as a pragmatic bedside alternative tool to assess nephrotoxicity.

GWAS meta-analysis of kidney function traits in Japanese populations.

BACKGROUND: Genetic epidemiological evidence for the kidney function traits in East Asian population including Japanese remain still relatively unclarified. Especially, the number of GWASs for kidney traits reported still remains limited, and the sample size of each independent study is relatively small. Given the genetic variability between ancestries/ethnicities, implementation of GWAS with sufficiently large sample sizes in specific population of Japanese is considered meaningful. METHODS: We conducted the GWAS meta-analyses of kidney traits by leveraging the GWAS summary data of the representative large genome cohort studies with about 200,000 Japanese participants (n = 202,406 for estimated glomerular filtration rate [eGFR] and n = 200,845 for serum creatinine [SCr]). RESULTS: In the present GWAS meta-analysis, we identified 110 loci with 169 variants significantly associated with eGFR (on chromosomes 1-13 and 15-22; p < 5×10-8), whereas we also identified 112 loci with 176 variants significantly associated with SCr (on chromosomes 1-22; p < 5×10-8), of which one locus (more than 1Mb distant from known loci) with one variant (CD36 rs146148222 on chromosome 7) for SCr was considered as the truly novel finding. CONCLUSIONS: The present GWAS meta-analysis of largest genome cohort studies in Japanese provided some original genomic loci associated with kidney function in Japanese, which may contribute to the possible development of personalized prevention of kidney diseases based on genomic information in the near future.

Diagnostic test accuracy of serum creatinine and cystatin C-based index for sarcopenia: a systematic review and meta-analysis.

BACKGROUND: Sarcopenia is an important prognostic factor, but its optimal screening methods remain challenging. Several new indices developed based on serum creatinine (Cr) and cystatin C (CysC) have been proposed to be diagnostic biomarkers for sarcopenia screening. OBJECTIVE: This review aimed to evaluate the diagnostic accuracy of serum Cr- and CysC-based indices for sarcopenia diagnosis. METHODS: We systematically searched MEDLINE, EMBASE, SCIE and SCOPUS from inception to 2 April 2023. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. A bivariate random-effects model was used to synthesise the pooled sensitivity, specificity and area under the curves of the summary receiver operating characteristic (SROC-AUC). RESULTS: We retrieved 936 publications and included 16 studies with 5,566 participants (mean age ranged: 51.0-78.4 years, 50.2% men). The prevalence of sarcopenia ranged from 7.8 to 69.5%. All included studies presented a moderate to high risk of bias. The serum Cr- and CysC-based indices showed moderate diagnostic accuracy for sarcopenia (pooled sensitivity: 0.67, 95% CI 0.57-0.75; pooled specificity: 076, 95% CI 0.67-0.83; pooled SROC-AUC: 0.78, 95% CI 0.74-0.81). The Cr/CysC ratio is the most widely studied index, followed by the Cr × eGFRcys index. Overall, both indicators had satisfactory and comparable performance in screening sarcopenia. CONCLUSION: Serum Cr- and CysC-based indices showed moderate diagnostic accuracy for sarcopenia. The most studied indices-the Cr/CysC ratio and Cr × eGFRcys index-had comparable diagnostic accuracy for evaluating sarcopenia and may serve as surrogate markers for sarcopenia. However, further validation is required to verify these findings.

Creatinine levels in French children with Down syndrome up to ten years old.

Assess creatinine levels in French children with Down syndrome (DS) on the basis of the relationship between creatinine levels and age. The study included 279 children with DS aged 0 to 10 years who had been regularly monitored between 2004 and 2021 in a single genetics department and who had had at least one creatinine measurement. The creatinine level curves were established by estimating the median and the quantiles of order 2.5 and 97.5% according to age. A Generalized Additive Model for Location, Scale, and Shape was used. The results showed higher creatinine levels in children with DS than in children from the general population.   Conclusion: The present results allow to propose an original chart of creatinine levels according to age in French children with DS, which should help optimize their medical management and improve the early detection of renal diseases. What is Known: • Creatinine is a product of muscle breakdown and depends on muscle mass and children with Down syndrome have muscle and growth characteristics that differ from those of the general paediatric population. • Serum creatinine values in Japanese children with DS are higher than those of children from the general Japanese population. What is New: • Creatinine values in French children with DS are higher than those of children from the general French population. • The proposed original chart for creatinine values according to age, specifically designed for individuals up to 10 years old, should serve for further investigation, prevention, and follow-up of children with DS.

Relationship between the serum creatinine concentrations of preterm neonates within 24 h of birth and their mothers before delivery.

BACKGROUND: Neonatal serum creatinine (n-sCr) concentrations during the first few days of life have been reported to correlate with the maternal serum Cr (m-sCr) concentrations. We aimed to derive a regression equation to describe the relationship between n-sCr within 24 h of birth in preterm neonates and m-sCr before delivery, and to perform multiple regression analysis to identify factors related to n-sCr and the difference between n-sCr and m-sCr. METHODS: We recruited preterm neonates who were treated at the University of the Ryukyus Hospital between March 2012 and October 2022. Patients with underlying diseases or conditions that might affect hemodynamics were excluded, as were patients whose n-sCr and m-sCr were not measured in pairs. A total of 278 cases were included in the analysis. RESULTS: The median (interquartile range) gestational age, birth weight, n-sCr, and m-sCr were 33.9 weeks (32.0-35.1 weeks), 1901 g (1579-2284 g), 0.55 mg/dL (0.48-0.64 mg/dL), and 0.47 mg/dL (0.42-0.57 mg/dL), respectively. The regression equation derived was n-sCr = 0.092 + 0.970 × m-sCr (R2 = 0.768, p < 0.001). The multiple regression analysis showed that m-sCr was the most potent influencer of n-sCr, and the ratio of placental weight to birth weight (PW/BW ratio) was the most potent influencer of the difference between n-sCr and m-sCr. CONCLUSIONS: We have obtained an approximate equation of n-sCr = 0.1 + m-sCr for preterm neonates. In addition, the high PW/BW ration may reduce the difference between n-sCr and m-sCr.

The use of concomitant medications on nephrotoxicity associated with teicoplanin: A retrospective observational study.

BACKGROUND: Teicoplanin (TEIC) is a nephrotoxic agent. However, little is known about the effects of concomitant medications on nephrotoxicity. In this study, we investigated the effects of concomitant drugs on nephrotoxicity. METHODS: A retrospective observational case-control study was conducted on patients (≥18 years) who started TEIC at the Tokyo Dental College, Ichikawa General Hospital, between January 2013 and April 2023. The primary outcome was nephrotoxicity, defined as an increase in serum creatinine levels of ≥50 % or ≥0.5 mg/dL from baseline. Logistic regression analysis was used to determine the risk factors for nephrotoxicity associated with TEIC. In addition, we investigated the relationship between nephrotoxicity and predicted free TEIC concentrations. RESULTS: Of 305 patients, 43 (14.1 %) developed nephrotoxicity. The multivariate logistic regression analysis identified that serum albumin (odds ratio [OR] = 0.50, 95 % confidence interval [CI] 0.27-0.89, p = 0.02), concomitant use of loop diuretics (OR = 2.22, 95 % CI 1.10-4.59, p = 0.03), antivirals (OR = 3.24, 95 % CI 1.32-7.62, p < 0.01), and vasopressors (OR = 2.57, 95 % CI 1.10-5.78, p = 0.03) were the associated risk factors for nephrotoxicity in patients administered with TEIC. In 216 patients, predicted TEIC concentrations were 3.6 [interquartile range (IQR), 2.6-4.9] µg/mL in the nephrotoxicity group versus 3.6 [IQR, 2.5-4.7] µg/mL in the non-nephrotoxicity group, with no significant difference (p = 0.69). CONCLUSION: Our results indicate the importance of modifying the concomitant use of loop diuretics, antivirals, and vasopressors.

Acute kidney injury surveillance in the high-risk neonatal population following implementation of creatinine screening protocol.

AIM: Acute kidney injury (AKI) in neonates is associated with longer hospital stays and higher mortality rates. However, there is significant variability in prevalence rates of AKI and the true burden is incompletely understood. In November 2020, the University of Iowa Stead Family Children's Hospital Neonatal Intensive Care Unit implemented a creatinine screening protocol to enhance kidney function monitoring. We sought to evaluate adherence to the protocol to determine if increased surveillance led to increased detection of AKI events. METHODS: A retrospective chart review was conducted for neonates born at <30 weeks' gestation admitted between 2015 and 2020. We reviewed 100 charts in both the pre (2015-2016) and post (2020-2021) implementation era of the AKI surveillance protocol. AKI was defined according to neonatal modified KDIGO criteria. RESULTS: Following implementation of the protocol, neonates were significantly more likely to have creatinine checked (p < 0.001). Serum creatinine was drawn according to protocol guidelines 68% of the time, and 42% of patients (34/82) had an 80% or higher adherence to the protocol. There was a significant increase in detection of AKI in the post-protocol cohort (13/82, incidence of 16%) compared to the pre-protocol cohort (5/83, incidence of 6%), (p = 0.047). CONCLUSION: The implementation of a serum creatinine screening protocol increased the frequency of creatinine draws and detection of AKI.

Continuous Urine Output-Based Alert Identifies Cardiac Surgery-associated Acute Kidney Injury Earlier Than Serum Creatinine: A Prospective and Retrospective Observational Study.

OBJECTIVE(S): Acute kidney injury (AKI) is defined and staged by reduced urine output (UO) and increased serum creatinine (SCr). UO is typically measured manually and documented in the electronic health record, making early and reliable detection of oliguria-based AKI and electronic data extraction challenging. The authors investigated the diagnostic performance of continuous UO, enabled by active drain line clearance-based alerts (Accuryn AKI Alert), compared with AKI stage 2 SCr criteria and their associations with length of stay, need for continuous renal replacement therapy, and 30-day mortality. DESIGN: This study was a prospective and retrospective observational study. SETTING: Nine tertiary centers participated. PARTICIPANTS: Cardiac surgery patients were enrolled. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 522 patients were analyzed. AKI stages 1, 2, and 3 were diagnosed in 32.18%, 30.46%, and 3.64% of patients based on UO, compared with 33.72%, 4.60%, and 3.26% of patients using SCr, respectively. Continuous UO-based alerts diagnosed stage ≥1 AKI 33.6 (IQR =15.43, 95.68) hours before stage ≥2 identified by SCr criteria. A SCr-based diagnosis of AKI stage ≥2 has been designated a Hospital Harm by the Centers for Medicare & Medicaid Services. Using this criterion as a benchmark, AKI alerts had a discriminative power of 0.78. The AKI Alert for stage 1 was significantly associated with increased intensive care unit and hospital length of stay and continuous renal replacement therapy, and stage ≥2 alerts were associated with mortality. CONCLUSIONS: AKI Alert, based on continuous UO and enabled by active drain line clearance, detected AKI stages 1 and 2 before SCr criteria. Early AKI detection allows for early kidney optimization, potentially improving patient outcomes.

Lower serum creatinine to cystatin C ratio associated with increased incidence of frailty in community-dwelling elderly men but not in elderly women.

BACKGROUND: Sarcopenia has been reported to play an important role in frailty syndrome. The serum creatinine/serum cystatin C ratio (Scr/Cys C ratio) has recently been recognized as a valuable indicator for assessing sarcopenia. However, few studies have examined the association between serum creatinine/serum cystatin C ratio and frailty. The objective of this study is to investigate the relationship between the serum creatinine/serum cystatin C ratio and frailty among older adults residing in the community. METHODS AND MATERIALS: A Total of 1926 community-dwelling older adults aged ≥ 60 years in the 2011 waves of the China Health and Retirement Longitudinal Study (CHARLS) were included. The participants' frailty status was determined using a 39 item frailty index (FI), which classified individuals as "robust" (FI ≤ 0.1), "pre-frailty" (0.1 < FI < 0.25), or "frailty" (FI ≥ 0.25). The Scr/Cys C ratio was determined by dividing the serum creatinine level (mg/dL) by the cystatin C level (mg/L). The one-way analysis of variance(ANOVA) and Chi-squared test (χ2)were applied to compare the differences between the 3 groups. Both linear regression and logistic regression models were used to further investigate the relationship between Scr/Cys C ratio and frailty. RESULTS: After adjusting for potential confounding factors, the study revealed that participants in the Q1 quartile of Scr/Cys C ratio had increased odds of frailty (Q1vs.Q4: OR = 1.880, 95% CI 1.126-3.139, p = 0.016) compared with those in the Q4 quartile group. In fully adjusted logistic regression models, male participants in the Q2 quartile of Scr/Cys C ratio were significantly correlated with higher odds of pre-frailty (Q2 vs.Q4: OR = 1.693, 95%CI 1.040-2.758, p = 0.034). However, this correlation was not observed in females (OR = 0.984, 95% CI 0.589-1.642, p = 0.950,). Additionally, the study observed an increase in both the frailty index and the incidence of frailty as age increased in both males and females. CONCLUSION: Among community-dwelling older adults, lower Serum creatinine to cystatin C ratio were found to be associated with increased odds of frailty prevalence in males.