Comparisons between the 2012 new CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations and other four approved equations. PLoS One. 2014;9:e84688. [PMID: 24454737 PMCID: PMC3890277 DOI: 10.1371/journal.pone.0084688]

Estimating eGFR using serum creatinine or cystatin C in healthy Vietnamese population

Very few studies worldwide have assessed the estimated glomerular filtration rate (eGFR) using serum cystatin C (ScysC) in comparison to the gold standard measured glomerular filtration rate (mGFR) with a gamma camera technique using 99m-Technetium-Diethylene Triaminepentoacetic Acid (99mTc-DTPA). To determine the eGFR formula with the most accurate estimate of glomerular filtration rate when compared with mGFR in a healthy population in Vietnam. We conducted a cross-sectional descriptive study of more than 100 adults without hypertension. The study subjects were examined for general characteristics and blood biochemistry tests to assess eGFR, and the glomerular filtration rate was measured using 99mTc-DTPA with the Gates technique to record mGFR. The estimated values of the eGFR formula were evaluated and compared with the actual mGFR using 99mTechnetium-DTPA. Serum creatinine (Scr) concentration showed a significant difference between males and females: 0.9 ± 0.1 versus 0.8 ± 0.1 (P < .001), while ScysC concentration did not show this difference. The mGFR in the age groups < 40, 40 to 59, and ≥ 60: 105.0 ± 9.9, 94.8 ± 8.6, and 93.4 ± 10.6, respectively (P < .001). The eGFR-CKD-EPI-cystatin C 2012 formula showed the highest positive correlation with mGFR (ΔGFR = -1.6, R = 0.68, P < .001). eGFR calculated using cystatin C does not require sex adjustment, whereas, for creatinine, sex adjustment is necessary. The eGFR-CKD-Epi-CysC formula showed the lowest difference and a strong correlation with mGFR.

Comparison of glomerular filtration rate estimating equations in older adults: A systematic review and meta-analysis

BACKGROUND

Debates persist regarding the performance of existing glomerular filtration rate (GFR) estimating equations in older individuals. We performed this meta-analysis to assess the accuracy and bias of six commonly used equations, including the Chronic Kidney Disease Epidemiology Collaboration creatinine equation (CKD-EPICr) and its combination with cystatin C (CKD-EPICr-Cys), with the corresponding pair of the Berlin Initiative Study equations (BIS1 and BIS2) and the Full Age Spectrum equations (FASCr and FASCr-Cys).

METHODS

PubMed and the Cochrane Library were searched for studies comparing estimated GFR (eGFR) with measured GFR (mGFR). We analyzed the difference in P30 and bias among the six equations and investigated subgroups based on the area (Asian and non-Asian), mean age (60-74 years and ≥75 years), and levels of mean mGFR (<45 mL/min/1.73m2 and ≥45 mL/min/1.73m2).

RESULTS

27 studies with 18,112 participants were included, all reporting P30 and bias. BIS1 and FASCr exhibited significantly higher P30 than CKD-EPICr. While no significant differences were observed between FASCr and BIS1, or among the three combined equations in terms of either P30 or bias. Subgroup analyses revealed FASCr and FASCr-Cys achieved better results in most situations. However, in the subgroup of mGFR<45 mL/min/1.73m2, CKD-EPICr-Cys had relatively higher P30 and significantly smaller bias.

CONCLUSIONS

Overall, BIS and FAS provided relatively more accurate estimates of GFR than CKD-EPI in older adults. FASCr and FASCr-Cys may be better suited for various conditions, while CKD-EPICr-Cys would be a better option for older individuals with impaired renal function.

Relationship of Frailty with Kidney Function in Adults More Than 60-Years-Old: Effect of Using Different Formulas to Estimate Glomerular Filtration Rate

Objective

Determine the relationship of renal function with frailty using different formulas for estimated glomerular filtration rate (eGFR).

Methods

Individuals who were 60-years-old or more (n=507) were recruited from August 2020 to June 2021, and the FRAIL scale was used to classify them as non-frail or frail. The three equations used to compute the eGFR were based on serum creatinine (eGFRcr), cystatin C (eGFRcys), or SCr+CysC (eGFRcr-cys). Renal function was classified using eGFR and defined as normal (≥90 mL/min/1.73m²), mild damage (59-89 mL/min/1.73m²), or moderate damage (≤60 mL/min/1.73m²). The relationship of frailty with renal function was analyzed. A subset of participants (n=358) was used to analyze changes in eGFR from 1 January 2012 to 31 December 2021 according to frailty and using the different eGFR equations.

Results

There were significant differences between the eGFRcr-cys and eGFRcr values in the frail group (P<0.05), but not the non-frail group; however, the differences between the eGFRcr-cys and eGFRcys values were significant in the frail and non-frail groups (P<0.001). Based on each eGFR equation, the prevalence of frailty increased as eGFR decreased (P<0.001), but there was no significant relationship after adjusting for age or the age-adjusted Charlson co-morbidity index. There were temporal declines in eGFR in all three frailty groups (robust, pre-frail, and frail), especially in the frail group (2.226 mL/min/1.73m² per year; P<0.001).

Conclusion

For older individuals who are frail, the eGFRcr value may not provide accurate estimates of renal function. Frailty is associated with a rapid decline in kidney function.

Comparison of Creatinine and Cystatin C to Estimate Renal Function in Geriatric and Frail Patients

The aim of this study was to compare estimated glomerular filtration rate (eGFR) with creatinine (eGFRcrea) and cystatin C (eGFRcys) in geriatric and frail patients. A retrospective, cross-sectional study was performed at a geriatric clinic in Stockholm (n = 95). The revised Lund−Malmö equation was used to calculate eGFRcrea and the Caucasian-Asian-Pediatric-Adult (CAPA) equation was used for eGFRcys. The absolute mean percentage difference between eGFRcrea and eGFRcys was used as a surrogate measure for accuracy in eGFR. Other outcome measures were consistency expressed in Lin’s concordance correlation coefficient and the proportion of consistent staging of renal failure. Subgroup analyses were performed with regard to frailty (according to Clinical Frailty Scale) and age. eGFRcys estimated lower GFR than eGFRcrea across the entire study population as well as in all subgroups (p < 0.05). Difference between the estimates increased with increasing frailty (r2 = 0.15, p < 0.01), but was not significantly affected by age (r2 = 0.004, p = 0.55). In conclusion, eGFRcys was significantly lower compared to eGFRcrea in geriatric and frail patients. Moreover, frailty had greater impact than age on the accuracy of eGFR. However, this study cannot determine if any of the estimates are preferable over the other in this patient group.

OUP accepted manuscript

Background

Methods

Results

Conclusions

Comparison of cystatin C-based and creatinine-based glomerular filtration rate in the prediction of postoperative residual hypertension in aldosterone-producing adenoma patients after adrenalectomy

Renal function is associated with postoperative residual hypertension in aldosterone-producing adenoma(APA) patients. Cystatin C-based glomerular filtration rate (GFR) can more accurately estimate renal function than creatinine-based methods. However, which renal function estimation method can more accurately predict postoperative hypertension in APA patients is still unknown. We recruited 180 APA patients who underwent adrenalectomy. Preoperative creatinine and cystatin C-based GFRs were calculated. Residual hypertension was defined as persistent hypertension > 140/90 mmHg or requiring anti-hypertensive medications 1 year after surgery. Sixty-five(36.1%) of the 180 APA patients had residual hypertension. Multivariate logistic regression and receiver operating characteristic (ROC) curve analysis showed a combination of creatinine and cystatin method CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine-cystatin GFR was significantly associated with residual postoperative hypertension and had the largest area under the ROC curve, which was statistically larger than that of Cockcroft-Gault creatinine-based GFR. In both net reclassification index and integrated discrimination index models, CKD-EPI creatinine-cystatin GFR significantly improved the discriminatory power of CG-GFR. Among these renal function estimations used in the presented study, creatinine-cystatin combined GFR was a precise method to predict residual postoperative hypertension in APA patients received adrenalectomy. These finding may help identify those patients with higher risk of residual hypertension after operation.

Estimation of renal function by three CKD-EPI equations in Chinese HIV/AIDS patients: A STROBE-compliant article

Assessing renal function accurately is important for human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) patients. Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) recommended three equations to calculate estimated glomerular filtration rate (eGFR). There is evidence that eGFR based on the combination of serum creatinine and cystatin C is the most accurate of the three equations. But there is limited data on the comparison of three CKD-EPI equations in Chinese HIV/AIDS patients. The aim of our study was to compare the three CKD-EPI equations in Chinese HIV/AIDS population and assess renal function.Cross-sectional, single center, prospective study.One hundred seventy two Chinese adult HIV/AIDS patients were enrolled, including 145 (84.3%) males and 27 (15.7%) females. Mean age was 40(±12) years old. Overall mean eGFR based on serum creatinine, cystatin C and the combination of the 2 markers was 112.6(±19.0) mL/min/1.73 m2, 92.0(±24.2)mL/min/1.73 m2, and 101.7(±21.8)mL/min/1.73 m2, respectively (P = .000). The eGFR calculated by serum creatinine alone is higher than eGFR calculated by combination of serum creatinine and cystatin C, and eGFR calculated by cystatin C individual is lower than eGFR calculated by combination of the 2 markers.Of the 3 CKD-EPI equations, the CKD-EPIscr-cys equation may have the most accuracy in evaluating renal function in Chinese HIV/AIDS patients while the CKD-EPIscr equation may overestimate renal function and the CKD-EPIcys equation may underestimate renal function.

The effects of aging on the renal function of a healthy population in Beijing and an evaluation of a range of estimation equations for glomerular filtration rate

We investigated how age affected renal function in healthy subjects in Beijing and compared different estimated glomerular filtration rate (eGFR) equations. Kidney function was evaluated by five equations: Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI); Modification of Diet in Renal Disease Study (MDRD); the Chinese version of the MDRD (MDRDc); Full Age Spectrum (FAS); and Berlin Initiative Study (BIS). A total of 46,708 subjects were enrolled and followed-up for 3 years. All showed an increase in sCr and a reduction in eGFR with increasing age. Over the 3 years, the eGFR and serum creatinine (sCr) remained unchanged in most subjects. Different equations showed good consistency; the intraclass correlation coefficients (ICC) was 0.849 for males, and 0.817 for females. The CKD-EPI equation yielded higher GFR values than the other equations (according to sCr levels). For subjects aged over 70 years, the BIS equation produced the lowest eGFR values. In summary, we observed that the renal function of individuals was relatively stable with increasing age, although different eGFR equations yielded data that varied across different populations of subjects and sCr levels.

The interaction between serum uric acid and triglycerides level on blood pressure in middle-aged and elderly individuals in China: result from a large national cohort study

Background

The purpose of the research was to explore the extent of interaction between triglycerides (TG) and serum uric acid (SUA) level with blood pressure (BP) in middle-aged and elderly individuals in China.

Methods

Data were selected from the China Health and Retirement Longitudinal Study (CHARLS), a cross-sectional study. 3345(46.99%) men with average ages of 60.24 ± 9.24 years and 3774 (53.01%) women with average ages of 59.91 ± 9.95 years were included in the study. Differences between gender, or between categories of blood pressure levels were evaluated by t-test or chi-square test. The adjusted associations between various characteristics and BP status were first compared using linear regression models, as appropriate. Then, A general linear model adjusted for confounding factors (socio-demographic characteristics [age, educational levels, marital status, place of residence], health behaviors [cigarette smoking, alcohol drinking, eating habits, social and leisure activities, accidental injury, physical activities], medical history [history of cardiovascular diseases, hepatitis history, antidiabetic drugs, history of antilipidemic medication, anti-hypertensive therapy], metabolic measures [C-reactive protein (CRP), hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), estimated glomerular filtration rate (eGFR), body mass index (BMI)]) was used to examine the synergistic effect of SUA and TG level on BP in middle-aged and elderly individuals in China.

Results

Age-adjusted partial Pearson’s correlation coefficient showed that SUA and TG level positively correlated with both systolic blood pressure (SBP) and diastolic blood pressure (DBP) in both men and women. Multiple linear regression analysis showed the TG level was significantly and positively associated with SBP and DBP in both men (SBP: β =0.068, P = 0.001; DBP: β =0.064, P = 0.002) and women (SBP: β =0.061, P = 0.002; DBP: β =0.084, P = 0.000), but SUA were significantly and positively associated with SBP in both men (SBP: β =0.047, P = 0.013) and women (SBP: β =0.040, P = 0.028), regardless of other confounding factors. After adjusting for related potential confounders, evidence of interaction between SUA and TG level on SBP (men: β = − 1.090, P = 0.726; women: β = − 0.692, P = 0.861) and DBP (men: β = − 1.026, P = 0.572; women: β = − 0.794, P = 0.842) was not observed.

Conclusion

The interaction effect of SUA and TG level on BP was not observed in our study. Moreover, high SUA level was significantly associated with SBP, while high TG level was strongly related to both DBP and SBP.

Body mass index and serum uric acid level: Individual and combined effects on blood pressure in middle-aged and older individuals in China

Few studies on the individual and combined analysis between serum uric acid (SUA) and body mass index (BMI) and blood pressure (BP) were conducted in individuals aged ≥45 years. We aimed to assess the extent to which BMI and SUA and their interaction affect BP in Chinese middle-aged and older adults.Data were selected from the China Health and Retirement Longitudinal Study (CHARLS). A total of 5888 individuals aged 45 to 96 was included. Differences between BMI, or between categories of blood pressure were evaluated by t test or chi-square test. The trend of related variables according to four BMI categories was also tested using contrast analysis. The adjusted associations between various characteristics and BP status were first compared using linear regression models, as appropriate. Then, general linear models adjusting for related potential confounders were used to examine the synergistic effect of SUA and BMI level on BP for middle-aged and elderly individuals in China.Age-adjusted partial Pearson correlation coefficient showed that BMI was significantly and positively correlated with BP both in male and female, SUA positively correlated with both systolic blood pressure (SBP) and diastolic blood pressure (DBP) in males with BMI <24.0 kg/m and females with BMI <24.0 kg/m. However, SUA level significantly and positively correlated with DBP, but not with SBP, in females with BMI ≥24.0 kg/m. Multiple linear regression analysis showed that BMI was independently associated with BP both in male and female, SUA significantly and positively associated with SBP in both males and females with BMI <24.0 kg/m, However, SUA level positively correlated with DBP in females with BMI <24.0 kg/m, but not with males with BMI <24.0 kg/m, independent of other confounding factors. A general linear model analysis adjusted for confounding factors did not reveal interaction between BMI, SUA levels and SBP (β=-1.404, P = .686 in males; β=-2.583, P = .575 in females) and DBP (β=-2.544, P = .263 in males; β=-2.619, P = .622 in females).No interaction between BMI, SUA levels, and BP was observed in either males or females; However, BMI was independently associated with BP both in male and female, SUA independently associated with SBP both in males and females with BMI <24.0 kg/m, and SUA independently associated with DBP in females with BMI ≥24.0 kg/m.

A Clinical Drug-Drug Interaction Study Assessing a Novel Drug Transporter Phenotyping Cocktail With Adefovir, Sitagliptin, Metformin, Pitavastatin, and Digoxin

A new probe drug cocktail containing substrates of important drug transporters was tested for mutual interactions in a clinical trial. The cocktail consisted of (predominant transporter; primary phenotyping metric): 10 mg adefovir-dipivoxil (OAT1; renal clearance (CL_R )), 100 mg sitagliptin (OAT3; CL_R ), 500 mg metformin (several renal transporters; CL_R ), 2 mg pitavastatin (OATP1B1; clearance/F), and 0.5 mg digoxin (intestinal P-gp, renal P-gp, and OATP4C1; peak plasma concentration (C_max ) and CL_R ). Using a randomized six-period, open change-over design, single oral doses were administrated either concomitantly or separately to 24 healthy male and female volunteers. Phenotyping metrics were evaluated by noncompartmental analysis and compared between periods by the standard average bioequivalence approach (boundaries for ratios 0.80-1.25). Primary metrics supported the absence of relevant interactions, whereas secondary metrics suggested that mainly adefovir was a victim of minor drug-drug interactions (DDIs). All drugs were well tolerated. This cocktail may be another useful tool to assess transporter-based DDIs in vivo.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

PrEP-RN: Clinical Considerations and Protocols for Nurse-Led PrEP

HIV pre-exposure prophylaxis (PrEP) is an increasingly important part of the HIV prevention armamentarium. Issues with PrEP, however, include access. We propose that one way to surmount this issue would be to have nurses provide PrEP. Although clinical guidelines exist for PrEP, they are overwhelmingly not targeted to nonprescriber clinicians. In this article, we overview current U.S. and Canadian PrEP guidelines and provide explicit guidance about how nurses can provide PrEP, including the clinical pathways and medical directives we use in our clinic. We call nurse-led provision of PrEP, PrEP-RN (Pre-Exposure Prophylaxis-Registered Nurse) and feel it may be an important step forward in HIV prevention.

Chronic kidney disease, cardiovascular risk markers and total mortality in older men: cystatin C versus creatinine

Background

It remains uncertain whether cystatin C is a superior marker of renal function than creatinine in older adults. We have investigated the association between estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations based on creatinine (CKD-EPIcr) and cystatin C (CKD-EPIcys), and cardiovascular risk markers and mortality in older adults.

Methods

This is a cross-sectional and prospective study of 1639 British men aged 71–92 years followed up for an average of 5 years for mortality. Cox survival model and receiving operating characteristic analysis were used to assess the associations.

Results

The prevalence of chronic kidney disease (CKD) was similar using the two CKD-EPI equations, although cystatin C reclassified 43.9% of those with stage 3a CKD (eGFR 45–59 mL/min/1.732, moderate damage) to no CKD. However, CKD stages assessed using both CKD-EPIcr and CKD-EPIcys were significantly associated with vascular risk markers and with all-cause and cardiovascular disease mortality. In all men with CKD (eGFR <60 mL/min/1.732), the HRs (95% CI) for all-cause mortality after adjustment for cardiovascular risk factors compared with those with no CKD were 1.53 (1.20 to 1.96) and 1.74 (1.35 to 2.23) using CKD-EPIcr and CKD-EPIcys, respectively. Comparisons of the two CKD equations showed no significant difference in their predictive ability for mortality (difference in area under the curve p=0.46).

Conclusion

Despite reclassification of CKD stages, assessment of CKD using CKD-EPIcys did not improve prediction of mortality in older British men >70 years. Our data do not support the routine use of CKD-EPIcys for identifying CKD in the elderly British male population.

A review of urinary angiotensin converting enzyme 2 in diabetes and diabetic nephropathy

Urinary angiotensin converting enzyme 2 (ACE2) is significantly increased in diabetes and diabetic nephropathy. While studies on its clinical significance are still underway, its urinary expression, association with metabolic and renal parameters has been in the recent past considerably studied. The recent studies have demystified urine ACE2 in many ways and suggested the roles it could play in the management of diabetic nephropathy. In all studies the expression of urinary ACE2 was determined by enzyme activity assay and/with the quantification of ACE2 protein and mRNA by methods whose reliability are yet to be evaluated. This review summarizes recent findings on expression of urinary ACE2, examines its relationship with clinical parameters and highlights possible applications in management of diabetic nephropathy.

Association and Interaction Analysis of Body Mass Index and Triglycerides Level with Blood Pressure in Elderly Individuals in China

Objectives

To assess the extent of interaction between body mass index (BMI) and triglyceride (TG) level and its effects on blood pressure (BP) in elderly individuals in China.

Design

Cross-sectional study.

Setting

Data were taken from a cross-sectional study called the China Health and Retirement Longitudinal Study.

Participants

The analytic sample included 3629 subjects aged 45 to 96 years.

Main Outcome Measurements

Data were obtained from the China Health and Retirement Longitudinal Study, which is a cross-sectional study. Age-adjusted partial Pearson's correlation test was used to compare various characteristics and BP. Adjusted associations were first used as linear regression models, as appropriate. Then, general linear models adjusted for related potential confounders were used to examine the synergistic effects of BMI and TG level on BP. Finally, a binary logistic regression model adjusted for confounding factors was used to examine the association between BMI or TG level and hypertension.

Results

Age-adjusted partial Pearson's correlation coefficient showed that the TG level was positively correlated with both systolic blood pressure (SBP) and diastolic blood pressure (DBP) in both men and women with BMI < 24.0 kg/m²; however, TG level was positively correlated with DBP in women with BMI ≥ 24.0 kg/m² but not with DBP in men with BMI ≥ 24.0 kg/m². Multiple linear regression analysis showed that BMI level was significantly and positively associated with both SBP and DBP in men and women with BMI < 24.0 kg/m², and TG level was significantly and positively associated with SBP in women with BMI < 24.0 kg/m², independent of other confounding factors. A general linear model analysis with adjustment for confounding factors (age, educational level, marital status, current residence, smoking, eating habits, taking activities, antidiabetic medication, antihypertensive therapy, fasting plasma glucose [FPG], low-density lipoprotein cholesterol [LDL-C], estimated glomerular filtration rate [eGFR], and serum uric acid [SUA]) showed no interaction between BMI and TG level and SBP (men, β = 0.572, P = 0.845; women, β = 0.122, P = 0.923) and DBP (men, β = -0.373, P = 0.810; women, β = 0.272, P = 0.828). A binary logistic regression model analysis with adjustment for confounding factors (age, educational level, marital status, current residence, smoking, drinking, eating habits, taking activities, major accidental injury, physical activity, history of cardiovascular disease, history of liver disease, antilipidemic medication, antidiabetic medication, antihypertensive therapy, FPG, LDL-C, high-density lipoprotein cholesterol [HDL-C], eGFR, and SUA) showed that overweight and obese men and women were more likely to have hypertension (men: odds ratio [OR] = 1.781, 95% confidence interval [CI] = 1.393–2.277; women: OR = 1.653, 95% CI = 1.330–2.055) and women with high TG were more likely to have hypertension (OR = 1.558, 95% CI = 1.219–1.992).

Conclusion

An interactive effect of BMI and TG level on BP was not observed in either men or women; however, independent effects of BMI on BP were observed in both men and women, and an association between TG level and hypertension was observed in women.

A comparison between 2017 FAS and 2012 CKD-EPI equations: a multi-center validation study in Chinese adult population

BACKGROUND

The recent guidelines recommend using the estimated glomerular filtration rate (eGFR) to evaluate renal function. There are two reported full-age-spectrum (FAS) equations in 2017, which are based on serum cystatin C concentrations with or without accompanying serum creatinine level (FAS_Cr-Cys or FAS_Cys). We compared the performance and assessed the applicability of the new FAS equation with the 2012 CKD-EPI (CKD-EPI_Cys and CKD-EPI_Cr-Cys) equation in Chinese subjects.

METHODS

A total of 1184 patients, mean aged 55.06 year who underwent ^99mTc-DTPA GFR measurements (rGFR) from four hospitals were enrolled. The bias (eGFR-rGFR), precision (interquartile range of difference [IQR]), and accuracy (the proportion of eGFR within 30% of rGFR [P30]) of eGFR and rGFR calculated by four equations were compared.

RESULTS

Generally, the equation based on the combination of Cys and Scr performed superior to that on the basis of Cys alone, either the CKD-EPI_Cr-Cys or the FAS_Cr-Cys. Detailedly, referred to rGFR (67.33 ml/min/1.73 m²), the CKD-EPI_Cys, CKD-EPI_Cr-Cys, FAS_Cys, and the FAS_Cr-Cys estimated GFR 56.46 ml/min/1.73 m², 62.79 ml/min/1.73 m², 56.45 ml/min/1.73 m², and 61.04 ml/min/1.73 m², gave ROC^AUC0.944, 0.954, 0.943, and 0.953, respectively. Another comparison as to bias, precision, P₃₀, and RMSE with FAS_Cr-Cys were - 2.87 ml/min/1.73 m², 19.01 ml/min/1.73 m², 74.16%, and 17.84 ml/min/1.73 m² showed that FAS_Cr-Cys performed approximately more accurate than other equations, as well as the diagnostic consistency of GFR staging. In the rGFR < 60 ml/min/1.73 m² subgroup, the FAS_Cr-Cys equation showed the best performance. In older subjects, compared with FAS_Cys, CKD-EPI_Cr-Cys, and CKD-EPI_Cys, the FAS_Cr-Cys equation had relatively less bias (- 8.09 vs. - 9.63, - 7.52, - 11.04, P < 0.05), most precise (15.18 vs. 16.32, 15.22, 16.63), and most accuracy, P₃₀ was statistically different from the other equations, and achieved a ideal value > 70%.

CONCLUSION

The performance of the FAS_Cr-Cys equation is better than that of the CKD-EPI_Cr-Cys equation in the Chinese population, particularly in the elderly. Yet, further modification of FAS equations from a large-scale study could be more suitable for the Chinese population, particularly in older people.

Corticosteroid therapy in IgA nephropathy with minimal proteinuria and high renal pathological score: A single‑center cohort study

Currently, there is no clear evidence that advocates the widespread use of corticosteroids for the treatment of immunoglobulin A nephropathy (IgAN) with minimal proteinuria (<1 g/day). The recent Kidney Disease: Improving Global Outcomes Clinical Practice Guideline recommends supportive corticosteroid treatment. In the present study, 45 IgAN patients with high renal pathological scores and minimal proteinuria were enrolled. The patients were randomly divided into two groups. The treatment group received methylprednisolone tablets in addition to angiotensin‑converting‑enzyme inhibitor (ACE‑I) and/or angiotensin‑receptor blocker (ARB) treatment. The control group only received ACE‑I and/or ARB treatment. In the treatment group, a single dose of 1 mg/kg (maximum 60 mg/day) methylprednisolone tablets was given daily followed by gradually decreasing dosage. The follow‑up time of the patients was 3 years. In addition, the underlying mechanisms were investigated. The results indicated that there was a significant reduction in the amount of urinary proteins in the treatment group compared with the control group. At the end of the follow‑up, the endpoint event rate of moderate or severe proteinuria and decrease in estimated glomerular filtration rate (eGFR) in the treatment group was significantly lower than the control group. Furthermore, higher levels of serum cytokines, interleukin (IL)‑4, IL‑17, transforming growth factor‑β1 and IL‑21, were detected in patients with IgAN compared with a group of healthy controls. There was no significant difference in IFN‑γ expression between the IgAN and healthy control groups. Furthermore, the expression of Janus kinase (Jak)1, Jak3, signal transducer and activator of transcription (STAT)3 and STAT6 was significantly upregulated in patients with IgAN compared with healthy controls. However, the expression levels of STAT5 and chaperone protein, C1GALT1 specific chaperone 1, in IgAN patients were significantly reduced compared with healthy controls. In addition, there was no significant difference in the expression of Jak2, tyrosine kinase 2, STAT1 and STAT4 between the two groups. In conclusion, for IgAN patients with minimal proteinuria and high renal pathological score corticosteroid therapy is likely to be effective. The dysregulation of serum cytokine levels in these patients with IgAN may have a role in the pathogenesis and progression of disease, which is associated with the activation of the JAK/STAT signaling pathway.

Proenkephalin, Neutrophil Gelatinase-Associated Lipocalin, and Estimated Glomerular Filtration Rates in Patients With Sepsis

Background

Proenkephalin (PENK) has been suggested as a novel biomarker for kidney function. We investigated the diagnostic and prognostic utility of plasma PENK in comparison with neutrophil gelatinase-associated lipocalin (NGAL) and estimated glomerular filtration rates (eGFR) in septic patients.

Methods

A total of 167 septic patients were enrolled: 99 with sepsis, 37 with septic shock, and 31 with suspected sepsis. PENK and NGAL concentrations were measured and GFR was estimated by using the isotope dilution mass spectrometry traceable-Modification of Diet in Renal Disease (MDRD) Study and three Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations: CKD-EPI_Cr, CDK-EPI_CysC, and CKD-EPI_Cr-CysC. The PENK, NGAL, and eGFR results were compared according to sepsis severity, presence or absence of acute kidney injury (AKI), and clinical outcomes.

Results

The PENK, NGAL, and eGFR results were significantly associated with sepsis severity and differed significantly between patients with and without AKI only in the sepsis group (all P<0.05). PENK was superior to NGAL in predicting AKI (P=0.022) and renal replacement therapy (RRT) (P=0.0085). Regardless of the variable GFR category by the different eGFR equations, PENK showed constant and significant associations with all eGFR equations. Unlike NGAL, PENK was not influenced by inflammation and predicted the 30-day mortality.

Conclusions

PENK is a highly sensitive and objective biomarker of AKI and RRT and is useful for prognosis prediction in septic patients. With its diagnostic robustness and predictive power for survival, PENK constitutes a promising biomarker in critical care settings including sepsis.

Comparative evaluation of technetium-99m-diethylenetriaminepentaacetic acid renal dynamic imaging versus the Modification of Diet in Renal Disease equation and the Chronic Kidney Disease Epidemiology Collaboration equation for the estimation of GFR

PURPOSE

We compared the performance of technetium-99m-diethylenetriaminepentaacetic acid (^99mTc-DTPA) renal dynamic imaging (RDI), the MDRD equation, and the CKD EPI equation to estimate glomerular filtration rate (GFR).

METHODS

A total of 551 subjects, including CKD patients and healthy individuals, were enrolled in this study. Dual plasma sample clearance method of ^99mTc-DTPA was used as the true value for GFR (tGFR). RDI and the MDRD and CKD EPI equations for estimating GFR were compared and evaluated.

RESULTS

Data indicate that RDI and the MDRD equation underestimated GFR and CKD EPI overestimated GFR. RDI was associated with significantly higher bias than the MDRD and CKD EPI equations. The regression coefficient, diagnostic precision, and consistency of RDI were significantly lower than either equation. RDI and the MDRD equation underestimated GFR to a greater degree in subjects with tGFR ≥ 90 ml/min/1.73 m² compared with the results obtained from all subjects. In the tGFR60-89 ml/min/1.73 m² group, the precision of RDI was significantly lower than that of both equations. In the tGFR30-59 ml/min/1.73 m² group, RDI had the least bias, the most precision, and significantly higher accuracy compared with either equation. In tGFR < 30 ml/min/1.73 m², the three methods had similar performance and were not significantly different.

CONCLUSIONS

RDI significantly underestimates GFR and performs no better than MDRD and CKD EPI equations for GFR estimation; thus, it should not be recommended as a reference standard against which other GFR measurement methods are assessed. However, RDI better estimates GFR than either equation for individuals in the tGFR30-59 ml/min/1.73 m² group and thus may be helpful to distinguish stage 3a and 3b CKD.

The Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of a TYK2/JAK1 Inhibitor (PF-06700841) in Healthy Subjects and Patients With Plaque Psoriasis

The safety, tolerability, pharmacokinetics, and pharmacodynamics of PF-06700841 were assessed in a randomized, double-blind, placebo-controlled, single- and multiple-dose escalation, parallel-group study in healthy subjects and patients with plaque psoriasis. The single ascending dose (1, 3, 10, 30, 100, or 200 mg) and multiple ascending dose (MAD; PF-06700841; up to 175 mg once daily or 50 mg twice daily for 10 days) periods included 54 healthy participants. In addition, 30 patients with psoriasis received PF-06700841 30 or 100 mg or placebo once daily for 28 days. Single PF-06700841 doses were rapidly absorbed, with peak plasma concentrations ≤ 1 hour, proportional exposure up to 100 mg, and mean half-life 3.8-7.5 hours. On day 10 of MAD, plasma concentrations peaked at ≤1.5 hours postdose (10-175 mg once daily). Elimination half-life was 4.9-10.7 hours; steady state was reached by day 8. In psoriasis patients on day 28, peak plasma concentrations occurred at 1-2 hours. Biomarkers IP-10 and high-sensitivity C-reactive protein were reduced and returned to near baseline levels after dosing. Maximal mean percent change from baseline in the Psoriasis Area and Severity Index scores for PF-06700841 30 mg once daily and 100 mg once daily were -67.92% and -96.31%, respectively, in week 4. All adverse events were mild/moderate. PF-06700841 was safe and well tolerated up to 200 mg once daily in healthy subjects and 100 mg once daily in patients with psoriasis, suggesting potential therapeutic utility in plaque psoriasis and other inflammatory diseases.

Accuracy of glomerular filtration rate estimationequations in patients with hematopathy

Renal dysfunction is a common side-effect of chemotherapeuticagents in patients with hematopathy. Although broadly used, glomerularfiltration rate (GFR) estimation equations were not fully validatedin this special population. Thus, this study was designed to furtherassess the accuracy of various GFR equations, including the newly2012 CKD-EPI equations. Referring to 99mTc-DTPA clearance method, three Scr-based (MDRD, Peking, and CKD-EPIScr), three Scys C-based (Steven 1, Steven 2, and CKD-EPIScys C), and three Scr-Scys C combination based (Ma,Steven 3, and CKD-EPIScr-Scys C) equationswere included. Bias, P30, and misclassificationrate were applied to compare the applicability of the selected equations.A total of 180 Chinese hematological patients were enrolled. Meanbias, absolute mean bias, P30, misclassificationrate and Bland-Altman plots of the CKD-EPIScr-Scys C equation were 7.90 mL/minute/1.73 m2,17.77 mL/minute/1.73 m2, 73.3%, 38% and79.7 mL/minute/1.73 m2, respectively. CKD-EPIScr-Scys C predicted the most precise eGFR both in lymphomaand leukemia subgroups. Additionally, CKD-EPIScys C equation in rGFR ≧ 90 mL/minute/1.73 m2 subgroup and Steven 2 equation in rGFR<90 mL/minute/1.73 m2 subgroup provided relatively more accurate estimatesin each subgroup.The CKD-EPIScr-Scys C equationcould be recommended to monitor kidney function in blood patients.The accuracy of GFR equations might be closely related with GFR leveland kidney function markers, but not the primary cause of hematopathy.

The association between creatinine versus cystatin C-based eGFR and cardiovascular risk in children with chronic kidney disease using a modified PDAY risk score

BACKGROUND

Children with chronic kidney disease (CKD) have a high prevalence of cardiovascular disease (CVD) risk factors which may contribute to the development of cardiovascular events in adulthood. Among adults with CKD, cystatin C-based estimates of glomerular filtration rate (eGFR) demonstrate a stronger predictive value for cardiovascular events than creatinine-based eGFR. The PDAY (Pathobiological Determinants of Atherosclerosis in Youth) risk score is a validated tool used to estimate the probability of advanced coronary atherosclerotic lesions in young adults.

OBJECTIVE

To assess the association between cystatin C-based versus creatinine-based eGFR (eGFR cystatin C and eGFR creatinine, respectively) and cardiovascular risk using a modified PDAY risk score as a proxy for CVD in children and young adults.

METHODS

We performed a cross-sectional study of 71 participants with CKD [median age 15.5 years; inter-quartile range (IQR) 13, 17], and 33 healthy controls (median age 15.1 years; IQR 13, 17). eGFR was calculated using age-appropriate creatinine- and cystatin C-based formulas. Median eGFR creatinine and eGFR cystatin C for CKD participants were 50 (IQR 30, 75) and 53 (32, 74) mL/min/1.73 m², respectively. For the healthy controls, median eGFR creatinine and eGFR cystatin were 112 (IQR 85, 128) and 106 mL/min/1.73m² (95, 123) mL/min/1.73 m², respectively. A modified PDAY risk score was calculated based on sex, age, serum lipoprotein concentrations, obesity, smoking status, hypertension, and hyperglycemia.

RESULTS

Modified PDAY scores ranged from -2 to 20. The Spearman's correlations of eGFR creatinine and eGFR cystatin C with coronary artery PDAY scores were -0.23 (p = 0.02) and -0.28 (p = 0.004), respectively. Ordinal logistic regression also showed a similar association of higher eGFR creatinine and higher eGFR cystatin C with lower PDAY scores. When stratified by age <18 or ≥18 years, the correlations of eGFR creatinine and eGFR cystatin C with PDAY score were modest and similar in children [-0.29 (p = 0.008) vs. -0.32 (p = 0.004), respectively]. Despite a smaller sample size, the correlation in adults was stronger for eGFR cystatin C (-0.57; p = 0.006) than for eGFR creatinine (-0.40; p = 0.07).

CONCLUSIONS

Overall, the correlation between cystatin C- or creatinine-based eGFR with PDAY risk score was similar in children. Further studies in children with CKD should explore the association between cystatin C and cardiovascular risk.

CKD-EPI creatinine-cystatin C glomerular filtration rate estimation equation seems more suitable for Chinese patients with chronic kidney disease than other equations

BACKGROUND

The aim of this study was to identify the optimal equation that accurately estimates the glomerular filtration rate (GFR) and the chronic kidney disease (CKD) stage in the Chinese population.

METHODS

A total of 1296 Chinese patients aged 18-65 years old were enrolled in this study. The estimated GFRs (eGFRs) calculated separately by three Diet in Renal Disease (MDRD) equations and three Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations were compared with the reference GFR (rGFR) measured by the ⁹⁹Tc^m-DTPA renal dynamic imaging method.

RESULTS

By Bland-Altman analysis, eGFR_cys and eGFR_{scr_cys} performed similarly, showing the tightest limits of agreement among the six equations. They also achieved the first and second highest 30% and 50% accuracies. Using a combination of the serum creatinine and cystatin C levels (eGFR_{scr_cys}) could improve the bias (-0.3 for eGFR_{scr_cys}) of the equation and achieve the highest diagnostic accuracy for renal insufficiency (AUC₆₀, 0.953; P < 0.05, except for eGFR__MDRD). All equations predicted stage 3 CKD with moderate accuracy (49.7-51.4%) and stage 5 CKD with good accuracy (90.2-96.4%). For stage 1 CKD, eGFR_cys showed a higher percentage of misclassification than the other equations. All equations seemed to perform poorly at predicting stage 2 and 4 CKD, as compared to the other CKD stages. eGFR_{scr_cys} was the best-performing equation in terms of accurate classification of the CKD stage based on the overall performance (kappa value, 0.423).

CONCLUSION

For a Chinese population, the CKD-EPI_{scr_cys} equation seems more suitable for estimating the GFR than the other equations. Each equation had its own advantages in predicting different CKD stages.

Estimating glomerular filtration rate by serum creatinine or/and cystatin C equations: An analysis of multi-centre Chinese subjects

AIM

Various equations based on serum creatinine or/and cystatin C, required further validation in a Chinese population. We compared the performance of six Chinese equations (Mascr, Peiscr, Macys, Fengcys, Mascr-cys and Fengscr-cys) with the CKD-EPI equations in multi-centre Chinese subjects and evaluated their applicability in clinical practice.

METHODS

A total of 1522 adult patients from four different hospitals of China were enrolled in the study. (99m) Tc-DTPA renal dynamic imaging was used as the reference GFR (rGFR), and serum creatinine and cystatin C were measured by standardized assays. An optimal score system was implemented in the study.

RESULTS

The average rGFR of recruited subjects was 67.30±28.89 mL/min per 1.73m(2) . All estimated GFR (eGFR) correlated well with rGFR. In accordance with Bland-Altman analysis, the Fengscr-cys equations achieved optimal overall performance (score 14 vs 0-6), with least bias (median difference, -0.57 mL/min per 1.73m(2) ; median absolute difference, 8.83 mL/min per 1.73m(2) ), best precision (17.99 mL/min per 1.73m(2) ), highest accuracy (percentage of eGFR within 15%, 30% and 50% of the rGFR (P15 , P30 and P50 ; 49.7%, 78.7% and 91.8%, respectively); root-mean-square-error (RMSE, 16.28)). The Fengcys equation, a typical cystatin C based equation, was another well-behaved formula with an impressive performance. The Ma equations performed much poorer than the CKD-EPI equations. Consistent results can be observed in the GFR- /age- and sex-specific subgroups, while none equation yielded ideal accuracy in GFR<60 mL/min per 1.73 m(2) subgroup.

CONCLUSION

The Fengscr-cys equation appeared to achieve the best performance for GFR estimation in overall Chinese adult patients. However, further research is warranted to improve the accuracy of available equations in GFR less than 60 mL/min per 1.73 m(2) individuals.

Modification of the 2012 CKD-EPI equations for the elderly Chinese

BACKGROUND

Our previous studies demonstrated that 2012 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations were inaccurate enough for estimating glomerular filtration rate in elderly Chinese. Thus, this study was constructed to modify these equations.

METHODS

A total of 839 subjects (aged ≥60 years) from four hospitals in China between October 2009 and December 2014 were included. A random sample of 674 (80.3 %) subjects was used as a training sample set, and the remaining 165 (19.7 %) subjects as the verification set. The equations were modified using the hill-climbing algorithm.

RESULTS

Compared with the original CKD-EPI equations, the accuracy assessment indexes (bias, precision, accuracy and misclassification) were obviously improved after modification. Bland-Altman analysis also demonstrated that this modification attempt gained success to some extent.

CONCLUSIONS

The modified 2012 CKD-EPI equations could be more accurate than the original equations for elderly Chinese individuals.

Performance of the creatinine and cystatin C-based equations for estimation of GFR in Chinese patients with chronic kidney disease

BACKGROUND

Currently, creatinine- or cystatin C-based glomerular filtration rate (GFR) estimation equation has been recommended to assess GFR in CKD patients. However, it is still obscure whether those equations performed consistently outstandingly in Chinese population.

METHODS

The equations were validated in a population totaling 632 participants (mean age 61.6 ± 12.3 years). The estimated GFR (eGFR) calculated separately by six equations (C-MDRD, C_cys, C_scr-cys, CKD-EPI_scr, CKD-EPI_cys, and CKD-EPI_scr-cys equations) was compared with the reference GFR (rGFR) measured by the ^99mTc-DTPA renal dynamic imaging method. Participants were divided into age and rGFR specific subgroups.

RESULTS

CKD-EPI_scr-cys equation had a larger area under receiver operating characteristic curve (ROC^AUC) and relative higher sensitivity (79.8 %) and specificity (93 %) to diagnose CKD. CKD-EPI_scr-cys and CKD-EPI_cys equations appeared to be more accurate with higher proportion of eGFR within 30 % of rGFR (P ₃₀) value. Those two equations performed as well in older people as in the younger population. The CKD-EPI_scr-cys equation acquired the highest P ₃₀ (80.9 %) in subgroups with rGFR ≥60 mL/min/1.73 m², while the CKD-EPI_cys equation yielded the best performance in the rGFR <60 mL/min/1.73 m² subgroup.

CONCLUSION

CKD-EPI_scr-cys formula had better capability to accurately evaluate GFR in the participants CKD stages 1-2 in Chinese ethnic. The application of the cystatin C-based equations may be the optimal one for patients of moderately to severely injured GFR. Considering the accuracy in the entire range of participants less ideally, the additional of the Chinese racial factor is assumed to be essential.

Prevalence, awareness and treatment of chronic kidney disease among middle-aged and elderly: The China Health and Retirement Longitudinal Study

AIM

To provide reliable estimates of the prevalence, awareness, and treatment of chronic kidney disease (CKD), and their distribution and related influencing factors in middle-aged and elderly population in China.

METHODS

A cross-sessional survey called the China Health and Retirement Longitudinal Study (CHARLS) was conducted in 2011-2012 in Chinese people aged 45 years or older. This was to evaluate the prevalence of CKD, disease awareness compared to other chronic diseases in the population, and whether they were being treated for their CKD. Estimated GFR (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration eGFR creatinine-cystatin C (eGFRcreat-cys) equation. CKD was defined as eGFR less than 60 mL/min per 1.73 m(2) . Multivariable logistic regressions were used to estimate odds ratios (ORs) for the risk factors.

RESULTS

The overall prevalence of CKD was 11.5% (95%CI: 10.1% ∼ 12.8%). It was higher in urban than rural population (13.0% vs 10.0%, P < 0.05). Among all patients with CKD, only 8.7% were aware of the diagnosis. 4.9% of the patients were receiving treatment. The proportion of those aware of their condition and those who were treated decreased with age in both sexes. Of those aware (8.9%), 55.9% were treated. 31.4% of the treated patients took Chinese traditional medicine.

CONCLUSIONS

There is a surprising prevalence of CKD in the Chinese middle-aged and elderly population, with disproportionately low awareness and treatment. A comprehensive strategy toward prevention, screening, treatment and control of CKD is needed to slow the epidemic of CKD.

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 (CysC). Other biomarkers such as albuminuria may precede kidney function decline and have demonstrated to have strong associations with 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 mL/min per 1.73 m². Equations combining CysC and SCr perform better than the equations using either CysC or SCr alone and are recommended in situations where CKD needs to be confirmed. Combining creatinine, CysC 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.

The impact of chronic renal insufficiency on vascular surgery patient outcomes

Renal insufficiency is associated with an increased incidence of poor outcomes, including cardiovascular events and death, in the general population. Renal dysfunction appears to have a particularly negative impact in patients undergoing vascular surgery and endovascular therapy. Although the exact mechanism is unknown, increased levels of inflammatory and biochemical modulators associated with adverse cardiovascular outcomes, as well as endothelial dysfunction, appear to play a role in the association between renal insufficiency and adverse outcomes. Outcomes after the surgical and endovascular treatment of abdominal aortic aneurysms, carotid disease, and peripheral arterial disease are all negatively affected by renal insufficiency. Patients with renal dysfunction may warrant intervention for the treatment of critical limb ischemia and symptomatic carotid stenosis, given the comparatively worse outcomes associated with medical management. Open repair of aortic aneurysms and carotid intervention for asymptomatic disease in patients with severe renal dysfunction should be performed with significant caution, as the risks of repair may outweigh the benefits in this population. Further study is needed to better delineate the risks of medical management for these conditions in patients with coexisting severe renal dysfunction. Lastly, current guidelines for the management of vascular diseases, including objective performance goals for critical limb ischemia, are likely not applicable in patients with severe renal insufficiency.

Application of creatinine- and/or cystatin C-based glomerular filtration rate estimation equations in elderly Chinese

Background

No conventional creatinine- or cystatin C-based glomerular filtration rate (GFR) estimation equation performed consistently outstandingly in elderly Chinese in our previous studies. This research aimed to further evaluate the performance of some recently proposed estimation equations based on creatinine and cystatin C, alone or combined, in this specific population.

Materials and methods

The equations were validated in a population totaling 419 participants (median age 68 [range 60–94] years). The estimated GFR (eGFR) calculated separately by ten equations was compared with the reference GFR (rGFR) measured by the ^99mTc-DTPA renal dynamic imaging method.

Results

Median serum creatinine, cystatin C, and rGFR levels were 0.93 mg/L, 1.13 mg/L, and 74.20 mL/min/1.73 m², respectively. The Chinese population-developed creatinine- and cystatin C-based (Cscr-cys) equation yielded the least median absolute difference (8.81 vs range 9.53–16.32, P<0.05, vs the Chronic Kidney Disease Epidemiology Collaboration serum creatinine equation), the highest proportion of eGFR within 15% and 30% of rGFR (P₁₅ and P₃₀, 55.13 and 85.44, P<0.05 and P<0.01, vs the Chronic Kidney Disease Epidemiology Collaboration serum creatinine equation), and the lowest root mean square error (14.87 vs range 15.30–22.45) in the whole cohort. A substantial agreement of diagnostic consistency between eGFR and rGFR (with a kappa 0.61–0.80) was also observed with the Cscr-cys equation. Moreover, measures of performance in the Cscr-cys equation were consistent across normal to mildly injured GFR strata and individuals aged ≤80 years. Among all the Cscr-cys equations, the elderly Chinese-developed creatinine-based (CEscr) equation performed best in this specific population. Nevertheless, none of the equations achieved ideal manifestation in the moderately to severely GFR-injured group or in individuals aged ≥80 years.

Conclusion

The Cscr-cys equation appeared to be optimal in elderly Chinese among the investigated equations. If cystatin C is not available, the CEscr equation is an acceptable alternative. A multicenter study with abundant subjects to develop an apposite formula for elderly Chinese is assumed to be essential.