Establishing the presence or absence of chronic kidney disease:Uses and limitations of formulas estimating the glomerular filtration rate

The development of formulas estimating glomerular filtration rate(eG FR) from serum creatinine and cystatin C and accounting for certain variables affecting the production rate of these biomarkers, including ethnicity, gender and age, has led to the current scheme of diagnosing and staging chronic kidney disease(CKD),which is based on e GFR values and albuminuria.This scheme has been applied extensively in various populations and has led to the current estimates of prevalence of CKD. In addition, this scheme is applied in clinical studies evaluating the risks of CKD and the efficacy of various interventions directed towards improving its course. Disagreements between creatinine-based and cystatin-based e GFR values and between e GFR values and measured GFR have been reported in various cohorts. These disagreements are the consequence of variations in the rate of production and in factors, other than GFR, affecting the rate of removal of creatinine and cystatin C. The disagreements create limitations for all e GFR formulas developed so far. The main limitations are low sensitivity in detecting early CKD in several subjects, e.g., those with hyperfiltration, and poor prediction of the course of CKD. Research efforts in CKD are currently directed towards identification of biomarkers that are better indices of GFR than the current biomarkers and,particularly, biomarkers of early renal tissue injury.

Risk estimation of chronic kidney disease in a leptospirosis endemic area: A case-control study from south Andaman Islands of India

Objective:To estimate the risk of chronic kidney disease in patients with leptospirosis.Methods:All reported(41890)and later confirmed leptospirosis(1990)cases from 2010-2020 were traced by universal sampling.386 Laboratory-confirmed leptospirosis cases were enrolled and 413 age,gender,area,and occupation matched healthy persons were included as controls.Variables including socio-demographic characteristics,medical history,and health-related behaviours were compared between the two groups and association between these variables and reduced estimated glomerular filtration rate(eGFR)was analyzed with multiple linear regression.Results:The median of eGFR was 49.0(27.0,75.0)mL/min/1.73 m^(2) in the cases and 96.0(72.0,121.0)mL/min/1.73 m^(2) in the controls,showing significant differences(P<0.001).Bivariate analysis showed that leptospirosis seropositivitiy,repeat leptospirosis infection,diabetes,male gender,working in field(sun exposure),COVID-19 infection and smoking had statistically significant association with reduced eGFR.Leptospirosis seropositivity had negative effects on eGFR.Multiple linear regression confirmed that leptospirosis seropositivity had negative effects on eGFR(unstandardised β coefficients=−30.86,95%CI−49.7 to−11.9,P<0.001).Conclusions:Chronic kidney disease is a complex disease with multiple risk factors involved.Exposure to leptospirosis is one of the essential factors in accelerating its progression.

Can Peripheral Venous Gases Replace Arterial Gases in a Patient with Chronic Kidney Disease?

Introduction: Metabolic acidosis (MA) is a frequent alteration in chronic kidney disease (CKD) that is associated with numerous complications, which is why its correction is recommended. Oral sodium bicarbonate is currently the treatment of choice. Objective: The objective is to determine if venous bicarbonate is equal to arterial bicarbonate in the follow-up of a patient with chronic kidney disease. Materials Methods: Single-center Cross-sectional studies in a cohort of adult patients with stage 4 - 5 CKD. Samples were taken between January 2022 and January 2023, in a Clinic in the city of Ibague/ Colombia obtained from the radial artery. The inclusion criteria were: not being treated with alkaline at the time of inclusion. Results: A total of 71 patients were included, 73.2% male (52) and 26.8% female (19), with different stages: stage 3 with 5.6% (4), stage 4 with 60.6% (43), stage 5 with 33.8% (23). 66.2% were diabetic, 88.7% had arterial hypertension, and 15.5% of the patients presented hematoma as a complication and pain associated with arterial puncture. The result of mean venous bicarbonate was 18.8 with a standard deviation of 2.3, arterial bicarbonate a mean of 19.4 with a standard deviation of 2.1 with a value of P 0.46, venous pH with a mean of 7.37 with a standard deviation of 0.48 and a mean arterial pH of 7.38 with a standard deviation of 0.48 with a P value of 0.01. Values of venous bicarbonate compared to arterial bicarbonate showed no statistically significant difference in patients with chronic kidney disease, but there were more complications such as hematoma and pain in patients in the arterial puncture cohort, because of this result venous bicarbonate corresponds to arterial bicarbonate, but has less risk of complications associated with the procedure. Conclusion: Metabolic acidosis is a frequent alteration in advanced chronic kidney disease, these results showed that the values of arterial and venous bicarbonate have no statistically significant differences, but there is a greater risk of complications with arterial blood gases, due to this, venous bicarbonate could be a useful tool for patients with chronic kidney disease.

Difference between CKD-EPI and MDRD equations in calculating glomerular filtration rate in patients with cirrhosis

AIM:To evaluate the difference between the performance of the (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations in cirrhotic patients. METHODS: From Jan 2004 to Oct 2008, 4127 cirrhotic patients were reviewed. Patients with incomplete data with respect to renal function were excluded; thus, a total of 3791 patients were included in the study. The glomerular filtration rate (GFR) was estimated by the 4-variable MDRD (MDRD-4), 6-variable MDRD (MDRD-6), and CKD-EPI equations.RESULTS:When serum creatinine was 0.7-6.8 mg/dL and 0.6-5.3 mg/dL in men and women, respectively, a significantly lower GFR was estimated by the MDRD-6 than by the CKD-EPI. Similar GFRs were calculated by both equations when creatinine was > 6.9 mg/dL and > 5.4 mg/dL in men and women, respectively. In predicting in-hospital mortality, estimated GFR obtained by the MDRD-6 showed better accuracy [81.72%; 95% confidence interval (CI), 0.94-0.95] than that obtained by the MDRD-4 (80.22%; 95%CI, 0.96-0.97), CKD-EPI (79.93%; 95%CI, 0.96-0.96), and creatinine (77.50%; 95%CI, 2.27-2.63). CONCLUSION: GFR calculated by the 6-variable MDRD equation may be closer to the true GFR than that calculated by the CKD-EPI equation.

Biomarkers in chronic kidney disease,from kidney function to kidney damage

Chronic kidney disease(CKD) typically evolves over many years, with a long latent period when the disease is clinically silent and therefore diagnosis, evaluation and treatment is based mainly on biomarkers that assess kidney function. Glomerular filtration rate(GFR) remains the ideal marker of kidney function. Unfortunately measuring GFR is time consuming and therefore GFR is usually estimated from equations that take into account endogenous filtration markers like serum creatinine(SCr) and cystatin C(Cys C). Other biomarkers such as albuminuria may precede kidney function decline and have demonstrated to have strong associationswith disease progression and outcomes. New potential biomarkers have arisen with the promise of detecting kidney damage prior to the currently used markers. The aim of this review is to discuss the utility of the GFR estimating equations and biomarkers in CKD and the different clinical settings where these should be applied. The CKD-Epidemiology Collaboration equation performs better than the modification of diet in renal disease equation, especially at GFR above 60 m L/min per 1.73 m2. Equations combining Cys C and SCr perform better than the equations using either Cys C or SCr alone and are recommended in situations where CKD needs to be confirmed. Combining creatinine, Cys C and urine albumin to creatinine ratio improves risk stratification for kidney disease progression and mortality. Kidney injury molecule and neutrophil gelatinase-associated lipocalin are considered reasonable biomarkers in urine and plasma to determine severity and prognosis of CKD.

Impact of chronic kidney disease on mortality in older adults treated with pacemaker implantation

Objective To investigate whether chronic kidney disease could negatively impact survival in older adults needing pacemaker implantation after admission for bradyarrhythmias. Methods This retrospective observational study considered 538 older adults consecutively admitted, who had been followed-up for 31 ± 20 months. Subjects with poor short-term prognosis were excluded. Charlson comorbidity index （CCI） and estimated glomerular filtration rate （eGFR） was calculated, along with the independent relationship between all-cause mortality and clinical data. Hazard Ratio （HR） was calculated by Cox regression analysis. Results Mean age of the population was 85 ± 3.7 years, and causes for implantation were atrioventricular block in 51.9% and other bradyarrhythmias in 48.1% of cases. Mean eGFR was 58.3 ± 24 mL/min per 1.73 m2, and mean CCI was 3.65 ± 2.28. Death for all-causes was recorded in 213 subjects. Deceased patients were older, had lower eGFR, higher comorbidity, higher prevalence of myocardial infarction, congestive heart failure, cerebrovascular disease, dementia and chronic pulmonary disease. Age （HR： 1.081, 95% CI： 1.044-1.119; P 〈 001）, CCI （HR： 1.651, 95% CI： 1.286-2.121, P 〈 001） and eGFR 〈 45 mL/min per 1.73 m2 （HR： 1.360, 95% CI： 1.024-1.806; P = 0.033） were predictors of death. Conclusions Renal dysftmction, as well as comorbidity, impacts negatively survival of older adults treated with pacemaker implantation because of bradyarrhythmias.

Risk factors and urinary biomarkers of non-albuminuric and albuminuric chronic kidney disease in patients with type 2 diabetes

BACKGROUND A number of recent studies indicate a transformation in the natural course of chronic kidney disease(CKD)in type 2 diabetes(T2D)patients:an increasing prevalence of declined renal function without proceeding to the accompanying elevation of albuminuria.It has been suggested that albuminuric and nonalbuminuric CKD patterns could be different in their phenotypes and pathogenic mechanisms.AIM To identify the risk factors and biomarkers of albuminuric and non-albuminuric patterns of CKD in patients with T2D.METHODS Three hundred sixty patients with T2D duration≥10 years were included in this observational cross-sectional study.The associations of a panel of demographic and clinical characteristics,complications,comorbidities,and metabolic and hematology parameters with albuminuric and non-albuminuric CKD patterns were analyzed.The urinary excretion of nephrin and podocin,two podocytespecific markers,and WAP-four-disulfide core domain protein 2(WFDC-2),a marker of tubulointerstitial fibrosis,was determined by ELISA in comparison with healthy controls.RESULTS Non-albuminuric CKD was associated with age≥65 years(P=0.0001),female sex(P=0.04),diabetes duration≥15 years(P=0.0009),and the use of diuretics(P=0.0005).Male sex(P=0.01),smoking(P=0.01),waist-to-hip ratio>1.0(P=0.01)and hemoglobin A1c(HbA1c)>8.0%(P=0.005)were risk factors for elevated albuminuria not accompanied by a decrease in estimated glomerular filtration rate(eGFR).Duration of diabetes≥15 years and the use of calcium channel blockers were risk factors for albuminuria with decreased eGFR(both P=0.01).In multivariate logistic regression analysis,age,HbA1c,female sex and diuretics were significant predictors for reduced eGFR,while waist-to-hip ratio,HbA1c and male sex were associated with elevated urinary albumin-to-creatinine ratio(UACR).Excretion of nephrin and podocin was increased in patients with albuminuria,regardless of decline in renal function(P<0.001),correlating positively with UACR.The urinary excretion of WFDC-2 was markedly higher in men than in women(P<0.000001).Men with T2D demonstrated increased WFDC-2 levels independently of the CKD pattern(all P<0.05).In T2D women,WFDC-2 excretion was increased in those with reduced renal function(P≤0.01),correlating negatively with eGFR.CONCLUSION The data provide further evidence that albuminuric and non-albuminuric CKD phenotypes correspond to different pathways of diabetic kidney disease progression.

Chronic kidney disease prediction is an inexact science: The concept of “progressors” and “nonprogressors”

In 2002,the National Kidney Foundation Kidney Disease Outcomes Quality Initiative(NKF KDOQI)instituted new guidelines that established a novel chronic kidney disease(CKD)staging paradigm.This set of guidelines,since updated,is now very widely accepted around the world.Nevertheless,the authoritative United States Preventative Task Force had in August 2012acknowledged that we know surprisingly little about whether screening adults with no signs or symptoms of CKD improve health outcomes and that we deserve better information on CKD.More recently,the American Society of Nephrology and the American College of Physicians,two very well respected United States professional physician organizations were strongly at odds coming out with exactly opposite recommendations regarding the need or otherwise for"CKD screening"among the asymptomatic population.In this review,we revisit the various angles and perspectives of these conflicting arguments,raise unanswered questionsregarding the validity and veracity of the NKF KDOQI CKD staging model,and raise even more questions about the soundness of its evidence-base.We show clinical evidence,from a Mayo Clinic Health System Renal Unit in Northwestern Wisconsin,United States,of the pitfalls of the current CKD staging model,show the inexactitude and unpredictable vagaries of current CKD prediction models and call for a more cautious and guarded application of CKD staging paradigms in clinical practice.The impacts of acute kidney injury on CKD initiation and CKD propagation and progression,the effects of such phenomenon as the syndrome of late onset renal failure from angiotensin blockade and the syndrome of rapid onset end stage renal disease on CKD initiation,CKD propagation and CKD progression to end stage renal disease all demand further study and analysis.Yet more research on CKD staging,CKD prognostication and CKD predictions are warranted.Finally and most importantly,cognizant of the very serious limitations and drawbacks of the NKF K/DOQI CKD staging model,the need to individualize CKD care,both in terms of patient care and prognostication,cannot be overemphasized.

Impact of creatinine methodology on glomerular filtration rate estimation in diabetes

AIM To evaluate the influence of creatinine methodology on the performance of chronic kidney disease(CKD)-Epidemiology Collaboration Group-calculated estimated glomerular filtration rate(CKD-EPI-eGFR) for CKD diagnosis/staging in a large cohort of diabetic patients. METHODS Fasting blood samples were taken from diabetic patients attending our clinic for their regular annual examination, including laboratory measurement of serum creatinine and eGFR.RESULTS Our results indicated an overall excellent agreement in CKD staging(kappa = 0.918) between the Jaffé serum creatinine-and enzymatic serum creatinine-based CKDEPI-eGFR, with 9% of discordant cases. As compared to the enzymatic creatinine, the majority of discordances(8%) were positive, i.e., associated with the more advanced CKD stage re-classification, whereas only 1% of cases were negatively discordant if Jaffé creatinine was used for eGFR calculation. A minor proportion of the discordant cases(3.5%) were re-classified into clinically relevant CKD stage indicating mildly to moderately decreased kidney function(< 60 m L/min per 1.73 m^2). Significant acute and chronic hyperglycaemia, assessedas plasma glucose and Hb A1 c levels far above the recommended glycaemic goals, was associated with positively discordant cases. Due to a very low frequency, positive discordance is not likely to present a great burden for the health-care providers, while intensified medical care may actually be beneficial for the small number of discordant patients. On the other hand, a very low proportion of negatively discordant cases(1%) at the 60 m L/min per 1.73 m^2 eGFR level indicate a negligible possibility to miss the CKD diagnosis, which could be the most prominent clinical problem affecting patient care, considering high risk of CKD for adverse patient outcomes. CONCLUSION This study indicate that compensated Jaffé creatinine procedure, in spite of the glucose-dependent bias, is not inferior to enzymatic creatinine in CKD diagnosis/staging and therefore may provide a reliable and cost-effective tool for the renal function assessment in diabetic patients.

Chronic kidney disease as a predictor of clinical risk in the elderly

Facing the needs of an increasingly ageing population is rapidly becoming a major public health issue in western countries, Chronic kidney disease （CKD）, whose current prevalence is estimated around 10%-15% in the general population, with considerably higher figures in at-risk groups, is widely known to increase with age. In the elderly, renal impairment is often concomitant or secondary to several other systemic disorders such as hypertension, atherosclerosis,

Efficacy and Safety of Diflstat for the Treatment of Secondary Dyslipidemia in Chronic Kidney Disease

1104 patients with Secondary Dyslipidemia and CKD （Chronic Kidney Disease） （females： 387; males： 717; aged： 70 4- 11 years） were given Diflstat with diet to evaluate efficacy and safety. The study lasted two years. Patients were assigned to three groups （A, B, C） based upon basal renal function. Group A consisted of 180 patients with GFR （glomerular filtration rate） of 67 4- 16 mL/min/m2. TC （Total-Cholesterol） （-31%）, LDLC （LDL-Cholesterol） （-42%）, TG （triglycerides） （-36.8%） levels, and nonHDLC （non HDLC holesterol） （-41%） and TC/HDLC ratio （-40%） were significantly reduced （P 〈 0.001）. GFR （＋2.5%） increased significantly. No significant changes were observed in HDLC （＋13%）. Group B was of 744 patients, 69% （males： 514）, 31% （females： 230） （median age： 70 ± 13 years）, and moderate stage Ill CKD （GFR： 38 ± 12 mL/min/l.73m2）. After 24 months the change of HDLC （＋3.5%） was not significant, while TC （-27%）, TG （-32%）, LDLC （-33%）, non-HDLC （33.4%）, TC/HDLC （-30%）, and GFR （＋2.1%） were statistically significant （P 〈 0.001）. Group C consisted of 180 patients, 51.6% （males： 93）, 48.3% （females： 87） （median age： 72±11 years）, with severe stage IV CKD （GFR： 19 mL/min/l.73m2）. HDLC （＋13%） was not significant, while TC （-32%）, TG （-38%）, LDLC （-35%）, non-HDLC （-38.5%）, TC/HDLC （-40%）, and GFR （＋2.1%） were statistically significant （P 〈 0.001）. An effective but safe lipid-lowering therapy in patients with CKD, may be crucial to prevent cardiovascular events. The treatment with Dill stat~ combined with diet is to be started as soon as possible in patients with CKD in order of improving lipid and lipoprotein profile, and reducing the progression of renal damage.

Relative performance of two equations for estimation of glomerular filtration rate in a Chinese population having chronic kidney disease

Background The new Chronic Kidney Disease Epidemiology Collaboration （CKD-EPI） equation was developed to address the systematic underestimation of glomerular filtration rate （GFR） by the Modification of Diet in Renal Disease （MDRD） Study equation in patients with relatively well-preserved kidney function.Performance of the new equation in the Chinese population is unknown.The goal of the present study was to compare performance of these two equations in Chinese patients with chronic kidney disease （CKD）.Methods We enrolled 450 Chinese patients （239 women and 211 men） with CKD in the present study.The renal dynamic imaging method was used to measure the referenced standard GFR （rGFR） for comparison with estimations using the two equations.Their overall performance was assessed with the Bland-Altman method and receiver-operating characteristics （ROC） analysis.Performance of the two equations in lower and higher estimated GFR （eGFR） subgroups was further investigated.Results Both eGFRs correlated well with rGFR （r=0.88,0.81,P〈0.05）.In overall performance,the CKD-EPI equation showed less bias,higher precision and improved accuracy,and was better for detecting CKD.In the higher-eGFR subgroup,the CKD-EPI equation corrected the underestimation of GFR by the abbreviated MDRD equation.Conclusions The CKD-EPI equation outperformed the abbreviated MDRD equation not only in overall performance but also in the subgroups studied.For the present,the CKD-EPI equation appears to be the first-choice prediction equation for estimating GFR.

Analysis of chronic kidney disease staging with different estimated glomerular filtration rate equations in Chinese centenarians

Background: Accurate estimation of the glomerular filtration rate (GFR) and staging of chronic kidney disease (CKD) are important. Currently, there is no research on the differences in several estimated GFR equations for staging CKD in a large sample of centenarians. Thus, this study aimed to investigate the differences in CKD staging with the most commonly used equations and to analyze sources of discrepancy. Methods: A total of 966 centenarians were enrolled in this study from June 2014 to December 2016 in Hainan province, China. The GFR with the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Berlin Initiative Study 1 (BIS1) equations were estimated. Agreement between these equations was investigated with the k statistic and Bland-Altman plots. Sources of discrepancy were investigated by partial correlation analysis. Results: The k values of the MDRD and CKD-EPI equations, MDRD and BIS1 equations, and CKD-EPI and BIS1 equations were 0.610, 0.253, and 0.381, respectively. Serum creatinine (Scr) explained 10.96%, 41.60% and 17.06% of the variability in these three comparisons, respectively. Serum uric acid (SUA) explained 3.65% and 5.43% of the variability in the first 2 comparisons, respectively. Gender was associated with significant differences in these 3 comparisons (P<0.001). Conclusions: The strengths of agreement between the MDRD and CKD-EPI equations were substantial, but those between the MDRD and BIS 1 equations and the CKD-EPI and BIS 1 equations were fair. The difference in CKD staging of the first 2 comparisons strongly depended on Scr, SUA and gender, and that of CKD-EPI and BIS1 equations strongly depended on Scr and gender. The incidence at various stages of CKD staging was quite different. Thus, a new equation that is more suitable for the elderly needs to be built in the future.

Effects of glycaemic management on diabetic kidney disease

Hyperglycaemia contributes to the onset and progression of diabetic kidney disease(DKD). Observational studies have not consistently demonstrated a glucose threshold, in terms of HbA1c levels, for the onset of DKD. Tight glucose control has clearly been shown to reduce the incidence of micro-or macroalbuminuria. However, evidence is now also emerging to suggest that intensive glucose control can slow glomerular filtration rate loss and possibly progression to end stage kidney disease. Achieving tight glucose control needs to be balanced against the increasing appreciation that glucose targets for the prevention of diabetes related complications need be individualised for each patient. Recently, empagliflozin which is an oral glucose lowering agent of the sodium glucose cotransporter-2 inhibitor class has been shown to have renal protective effects. However, the magnitude of empagliflozin's reno-protective properties are over and above that expected from its glucose lowering effects and most likely largely result from mechanisms involving alterations in intra-renal haemodynamics. Liraglutide and semaglutide, both injectable glucose lowering agents which are analogues of human glucagon like peptide-1 have also been shown to reduce progression to macroalbuminuria through mechanisms that remain to be fully elucidated. Here we review the evidence from observational and interventional studies that link good glucose control with improved renal outcomes. We also briefly review the potential reno-protective effects ofnewer glucose lowering agents.

The role of endothelial biomarkers in predicting damp-heat syndrome in diabetic kidney disease

Objective:To explore the role of endothelial biomarkers in predicting damp-heat syndrome in diabetic kidney disease(DKD).Methods:A total of 183 patients with DKD were divided into 3 groups:the early DKD group,established DKD group,and advanced DKD group.All patients were classified according to traditional Chinese medicine(TCM)syndrome type,and clinical indexes were collected for statistical analysis.Results:A total of 183 DKD patients were included in this study.Fibroblast growth factor 23(FGF23),chitinase-3-like protein 1(CHI3L1),endocan,tumor necrosis factor receptor 1(TNFR1),secretory leukocyte protease inhibitor(SLPI),and vascular endothelial growth factor A(VEGF-A)were increased in advanced DKD.FGF23,CHI3L1,endocan,SLPI,and TNFR1 showed a negative correlation with estimated glomerular filtration rate(eGFR),while they had a positive correlation with 24 h urine protein.After adjusting for age,gender,diabetes duration,body mass index(BMI),hemoglobin,glucose,uric acid,24 h urine protein,cholesterol,triglyceride,low-density lipoprotein,and hemoglobin A1c(HbA1c),the multiple regression analysis showed that FGF23,endocan,TNFR1,and SLPI significantly correlated with eGFR.Conclusions:FGF23,endocan,TNFR1,and SLPI are elevated in advanced DKD compared with early stage,and they may take part in the pathogenesis and progression of DKD.Our study provides useful biomarkers for predicting the appearance of damp-heat syndrome,including FGF23,endocan,TNFR1,and SLPI.

Assessment of Cystatin C-Based GFR Estimating Equations as a Novel Reliable Biomarker for Renal Pathology Diagnosis in Patients with Mild to Severe Tubular Affection

Background and Objective: Serum creatinine, a commonly used biomarker in determining glomerular filtration rate (GFR) and chronic kidney disease (CKD) stage, is highly variable biologically and does not rise until > 50% of renal function (RF) impairment occurs. Also, its production is not constant & is affected by many factors as muscle mass, age, inflammation. On the other hand, Cystatin C shows more stable production making it more suitable for assessment of kidney function. Also, It has been shown that the progression of CKD to renal failure, even in glomerular diseases, correlated better with the degree of tubular damage and interstitial fibrosis. So, our aim was to investigate the relation between kidney function assessed by different cystatin (Cys-C)-based estimated glomerular filtration rate (eGFR) in comparison to the gold standard Iohexol (Ioh) based measured (m)GFR in relation to the pathological degree of tubular damage in renal biopsy. To our knowledge, this is the first study that evaluates the relation of (Cys-C)-based eGFR to tubulointerstitial fibrosis in renal biopsy. Methods: This cross-sectional study was performed on 20 CKD cases who attended the Nephrology Department at Ain Shams University, where a renal biopsy was obtained, and individuals were allocated into two groups: group A (GA) with mild tubular affection (TA) and group B (GB) with moderate to severe TA. All participants were referred for measure-ment of GFR using Iohexol (Ioh) together with serum Cys-C level and eGFR was calculated using different Cys-C-based GFR estimating equations, which were further compared using Multivariate Linear Regression and Bland-Altman analyses. Results: Our results revealed a substantial statistical difference among the two studied groups regarding Hb, s creatinine, urea. GB had significantly lower levels for both eGFR and mGFR (82, 93, 115, or 115) ml/min/1.73m2, Vs. GA (200, 123, 162 or 124) ml/min/1.73m2, according to GFR_iohexol, Stevens, Grubb, and CKD_EPI_CYST equations, respectively, p 0.05. A significant correlation between CKD-EPI CYST and mGFR_Iohexol (Ioh) for GA was found (R = 0.601, p = 0.030), where there was a non-substantial relation between any of the used equations and the mGFR in category B (p > 0.05). There was no independent association between the eGFR results and Iohexol clearance. Stevens eGFR had the highest-level bias 33.9 compared with CKD_EPI_CYST (28) and Grubb eGFR (22.85). Conclusion: eGFR by CysC-based equations underestimate GFR in comparison to GFR-iohexol. There is significant correlation between eGFR by CysC-based equations and the gold standard GFR-iohexol only in mild degree of tubular affection and only with CKD-EPI-CYST equation. Stevens equation showed the highest bias while Grubb equation showed the least bias. Although cystatin-based equations have demonstrated a high level of correlation with measured GFR, they are still regarded as imprecise and cannot be established as equal to measured GFR or as a gold standard for GFR estimate.

血清肌酐的特异性分析及新eGFR公式的适用性研究

目的验证血清肌酐(Cr)参考区间的适用性及不同影响因素下Cr的分布特征,探讨不同估算肾小球滤过率(eGFR)公式在慢性肾脏病中的差异及新公式的验证。方法选取2020年9月1日至2023年8月31日该院实验室信息系统中健康体检者的数据。采用偏度-峰度法判断数据正态性,Box-Cox法转换偏态数据,四分位间距法剔除离群值。Mann-Whitney U检验、Kruskal-Wallis单因素方差分析及协方差分析比较Cr在性别、年龄及季节上的差异。参照我国行业标准对现行的Cr参考区间进行适用性验证。另选取同期住院的慢性肾脏病患者数据,以目前实验室在用的CKD-EPI Cr2009公式为标准,验证法国新开发的MMB-eGFR公式。Spearman相关、Deming回归及Bland-Altman图分析两种估算公式结果的相关性、线性关系与一致性。结果纳入健康体检者数据54710例。Cr在性别、年龄、季节间差异均有统计学意义:男性Cr水平明显高于女性(P<0.001);除20~<30岁与30~<40岁外,其余年龄段间差异有统计学意义(P<0.001),随年龄增长,Cr水平升高;男、女性Cr水平在四季之间变化呈“对号”形和“倒梯”形。上述数据均用于Cr参考区间的适用性验证,各亚组通过率均大于90%。筛选慢性肾脏病患者数据后,纳入研究336例,进行CKD-EPI Cr2009和MMB-eGFR结果间的比较,两种估算公式的结果呈正相关(r=0.943,P<0.001),并且存在线性关系,具有92.86%的一致性。结论血清Cr水平在年龄、性别、季节方面的差异均有统计学意义。行业标准中提供的Cr参考区间适用于长春地区。MMB-eGFR与CKD-EPI Cr2009公式一致性较高,适用于该地区。

新型冠状病毒感染对未接受肾脏替代治疗的慢性肾脏病患者肾功能的长期影响

目的 探讨新型冠状病毒感染(COVID-19)对未接受肾脏替代治疗的慢性肾脏病(CKD)患者肾功能的长期影响。方法 选取贵州航天医院2022年12月—2023年3月收治的确诊COVID-19时估算肾小球滤过率(eGFR)<60 mL/(min·1.73 m^(2))的39例CKD患者纳入COVID-19组,另选取2021年9—12月收治的未患COVID-19的40例CKD患者纳入对照组。比较2组患者的eGFR变化情况,基于混合线性模型分析COVID-19组eGFR水平随时间的变化。结果 COVID-19组患者的基线eGFR水平和随访1、3个月时的eGFR水平与对照组比较,差异均无统计学意义(P>0.05);随访1年时,COVID-19组患者的eGFR水平低于对照组,差异有统计学意义(P<0.05)。混合线性模型分析结果显示,COVID-19组患者发生COVID-19后1年内eGFR水平下降1.84 mL/(min·1.73 m^(2)),相当于较基线水平下降4.62%,其中糖尿病患者的eGFR水平下降幅度最大(7.45%)。结论 未接受肾脏替代治疗的CKD患者发生COVID-19后1年内eGFR大幅下降,肾功能恶化加剧,应接受密切的长期肾功能监测和及时干预。

5种估算肾小球滤过率计算公式对肾脏滤过功能进行评估的临床应用评价

目的 评估肾脏病膳食改良试验(MDRD)、MDRD中国公式(MDRD_(CHN))、慢性肾病流行病学协作组(CKD-EPI)_(Cr)、CKD-EPI_(CysC)、CKD-EPI_(Cr-CysC)5种估算肾小球滤过率(eGFR)公式在评价肾小球滤过功能和诊断慢性肾病(CKD)的临床应用价值,明确最适公式。方法 纳入2 610例宁波大学附属第一医院门诊和住院患者作为研究对象,检测血清肌酐(Cr)和半胱氨酸蛋白酶抑制剂C(CysC)水平,分别采用5种公式评估eGFR,比较不同公式计算值的差异性。选取412例住院患者,以内生肌酐清除率(cCr)作为参考方法,分析其与5种eGFR结果的相关性,绘制受试者工作特征(ROC)曲线比较5种eGFR计算值诊断CKD的效能。选取239例健康人群,建立本实验室eGFR参考区间。结果 5种eGFR计算结果均呈偏态分布,两两比较差异大多具有统计学意义。5种eGFR与cCr均呈显著正相关,其中CKD-EPI_(Cr-CysC)的相关系数最高(r=0.903)。5种eGFR诊断CKD的ROC曲线下面积依次为0.968、0.969、0.970、0.967和0.976,CKD-EPI_(Cr-CysC)的诊断效能最佳(敏感性97.3%、特异性89.8%)。5种公式的健康人群95%可信区间下限分别为76、87、82、99和93mL/min/1.73m2。结论 在评估肾小球滤过功能和诊断CKD方面,以参考区间下限为93 mL/min/1.73m2的CKD-EPI_(Cr-CysC)公式诊断效率最佳,值得在宁波地区推广应用。

Significant methodologic variations in calculating renal function changes following kidney tumor surgery:A quality reporting issue?

Renal tumor surgery places patients at increased risk for chronic kidney disease(CKD). Accurate quantification of kidney function changes before and after surgery is essential to determine the magnitude of decline attributable to an index procedure. Current literature, however, highlights heterogeneity and inconsistencies in measurement techniques thereby contributing to ambiguity amongst studies. Further efforts are necessary to standardize reporting of kidney function outcomes related to renal surgery.