Comparisons of GFR estimation using the CKD Epidemiology Collaboration (CKD-EPI) equation and other creatinine-based equations in Asian population: a systematic review

GFRs in Chinese CKD: A systematic review

PURPOSE

This was an evidence-based study to assess which creatinine-based equation was most useful for estimated glomerular filtration rate (eGFR) in Chinese adults with chronic kidney disease (CKD).

METHODS

Multiple databases were searched to collect relevant studies on creatinine-based eGFR equations for Chinese adults with CKD in Chinese and English from January 2009 to January 2023, using "glomerular filtration rate", "GFR equations", "Chinese CKD", "chronic kidney disease", "equation development" and "equation validation". The quality of each study was assessed using the diagnostic test accuracy review by RevMan 5.4 software. The equation name, study publication year, first author, reference method for eGFR, CKD numbers, age (age ranges) of individuals, mGFR value, bias, precision, and 30% accuracy (P30) of each included equation were recorded accordingly by 2 independent investigators.

RESULTS

Of the 838 studies identified, 23 studies based on 6 creatinine-based GFR equations were included in the present review, ie, the CKD-EPI, Asian modified CKD-EPI, FAS, EKFC, Xiangya, and BSI1 equations. A total of 2979 CKD patients were included for FAS equation external assessment, and the total P30 was 72.6 %; 970 CKD patients for the EKFC equation, and the total P30 was 73.1 %. 1778 CKD patients (≥60 years of age) with a mean eGFR from 39.7 to 47.6 mL/min/1.73 m2 were pooled to assess the prediction accuracy of the BSI1 equation and demonstrated that the bias was small (-3.8-3.5 mL/min/1.73 m2), the precision was excellent (10.2-16.8 mL/min/1.73 m2), and the total P30 was 69.6 %.

CONCLUSIONS

Currently, the FAS and EKFC equations have higher P30 for eGFR among Chinese adult CKD patients. The bias and precision of BSI1 formulas was acceptable for eGFR in elderly ≥ 60 years of age, while the P30 was relatively low. Therefore, there is a clinical need to develop more accurate equations for eGFR in older CKD adults. While promising, these findings require further validation in large well controlled clinical studies.

Ultrasound viscoelastic imaging in the noninvasive quantitative assessment of chronic kidney disease

BACKGROUND

This study aims to evaluate the clinical application value of ultrasound viscoelastic imaging in noninvasive quantitative assessment of chronic kidney disease (CKD).

METHODS

A total of 332 patients with CKD and 190 healthy adults as a control group were prospectively enrolled. Before kidney biopsy, ultrasound viscoelastic imaging was performed to measure the mean stiffness value (Emean), mean viscosity coefficient (Vmean), and mean dispersion coefficient (Dmean) of the renal. CKD patients were divided into three groups based on estimated glomerular filtration rate. The differences in clinic, pathology, ultrasound image parameters between the control and patient groups, or among different CKD groups were compared. The correlation between viscoelastic parameters and pathology were analyzed.

RESULTS

Emean, Vmean, and Dmean in the control group were less than the CKD group (p < 0.05). In the identification of CKD from control groups, the area under curve of Vmean, Dmean, Emean, and combining the three parameters is 0.90, 0.79, 0.69, 0.91, respectively. Dmean and Vmean were increased with the decline of renal function (p < 0.05). Vmean and Dmean were positively correlated with white blood cell, urea, serum creatinine, and uric acid (p < 0.05). Vmean is positively correlated with interstitial fibrosis and inflammatory cell infiltration grades (p < 0.001).

CONCLUSIONS

Ultrasound viscoelastic imaging has advantages in noninvasive quantitative identification and evaluating renal function of CKD. Emean > 6.61 kPa, Vmean > 1.86 Pa·s, or Dmean > 7.51 m/s/kHz may suggest renal dysfunction. Combining Vmean, Dmean, and Emean can improve the efficiency of identifying CKD.

Reporting chronic kidney disease in Greenland

Background: Chronic kidney disease (CKD) is a major health burden affecting more than 10% of the global population. It is a multifactorial disease with many risk factors attributed lifestyle diseases. The prevalence of CKD in Greenland is unknown; however, the prevalence of risk factors contributing to CKD is increasing.Objectives: To estimate the prevalence of CKD in Greenland.Methods: The study was a cross-sectional register-study including all Greenlandic residents aged ≥20 years with serum creatinine analysis within the last 2 years. We identified those with CKD based on eGFR and UACR and those registered with a CKD diagnosis code. Two limitations of the study are possible lack of data completeness and the reliance of a single time point to report CKD.Results: A total of 2,157 patients were identified with CKD with an age-standardised prevalence of 3.01%. Only 75 patients were registered with a diagnosis code for CKD. Approximately 80% of patients were classified with CKD stages 1-2.Conclusion: This is the first study reporting CKD in Greenland. We found a lower prevalence of CKD than reported by other studies, and a low number of patients correctly diagnosed with CKD. We call for increased awareness and diagnosis coding of CKD in Greenland.

Estimating glomerular filtration rate with new equations: can one size ever fit all?

Glomerular filtration rate (GFR) is thought to be the best overall indicator of kidney health. On an individual patient basis, a working knowledge of GFR is important to understand the future risk for chronic kidney disease (CKD) progression, enhanced risk for cardiovascular disease and death, and for optimal medical management including the dosing of certain drugs. Although GFR can be directly measured using exogenous compounds that are eliminated by the kidney, these methods are not scalable for repeated and routine use in clinical care. Thus, in most circumstances GFR is estimated, termed estimated GFR (eGFR), using serum biomarkers that are eliminated by the kidney. Of these, serum creatinine, and to a lesser extent cystatin C, are most widely employed. However, the resulting number is simply a population average for an individual of that age and sex with a given serum creatinine and/or cystatin C, while the range of potential GFR values is actually quite large. Thus, it is important to consider characteristics of a given patient that might make this estimate better or worse in a particular case. In some circumstances, cystatin C or creatinine might be the better choice. Ultimately it is difficult, if not impossible, to have an eGFR equation that performs equally well in all populations. Thus, in certain cases it might be appropriate to directly measure GFR for high consequence medical decision-making, such as approval for kidney donation or prior to certain chemotherapeutic regimens. In all cases, the eGFR thresholds of CKD stage should not be viewed as absolute numbers. Thus, clinical care should not be determined solely by CKD stage as determined by eGFR alone, but rather by the combination of an individual patient's likely kidney function together with their current clinical situation.

Associations of long-term mortality with serum uric acid at admission in acute decompensated heart failure with different phenotypes

BACKGROUND AND AIMS

It remains unclear whether the long-term prognostic value of serum uric acid (SUA) at admission differs in acute decompensated heart failure (HF) patients across the spectrum of left ventricular ejection fraction (EF).

METHODS AND RESULTS

In 2375 patients (38.9% women; mean age, 68.8 years), we assessed the risk of long-term (>1 year) all-cause mortality associated with per 1-SD increase in SUA at admission, using multivariable Cox regression in HF with preserved (HFpEF), mildly reduced (HFmrEF) and reduced (HFrEF) EF. During a median follow-up of 4.1 years, the long-term mortality rate was 39.9%. In all patients, the multivariable-adjusted hazard ratio (HR) expressing the risk of long-term mortality associated with SUA was 1.18 (95% CI, 1.11-1.26; P < 0.001). Compared with the low tertile of the SUA distribution, the sex- and age-adjusted cumulative incidence of long-term mortality was higher in the top tertile. In patients with HFpEF and HFrEF, SUA predicted the risk of long-term mortality with HRs amounting to 1.12 (95% CI, 1.02-1.21; P = 0.012) and 1.28 (95% CI, 1.12-1.47; P < 0.001), respectively. However, there were no associations between the risk of mortality and SUA in HFmrEF. Furthermore, age, sex, NYHA class, and the prevalence of coronary heart disease interacted significantly with SUA for predicting long-term mortality.

CONCLUSION

Higher levels of SUA at admission were associated with higher risk of long-term mortality in patients with different HF subtypes. The risk conferred by SUA was age and sex dependent. Our observations highlight that measuring SUA at admission may help to improve risk stratification.

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

Background

The accuracy of the measurement of renal function in potential living kidney donors (PLKD) is essential. The direct measurement of glomerular filtration rate (mGFR) has been considered the "gold standard." The estimated GFR (eGFR) with 24-hour urinary creatinine clearance (CrCl) is frequently used because of its availability. We aim to evaluate the correlation and agreement of eGFR using serum-based creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI) and the eGFR based on 24-hour urinary CrCl to evaluate kidney function in PLKD.

Methods

We evaluated the kidney function in 799 PLKD using 24-hour urinary CrCl method and compared the correlation and agreement with the eGFR based on creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI). We calculated the mean bias (difference), precision (SD of this difference), accuracy, and performed Bland-Altman plots.

Results

A total of 799 PLKD were analyzed. The age of the PLKD ranged from 18 to 73 years. Weak to mild correlation was observed between 24-hour urinary CrCl and all formulas (ranged from 0.31 to 0.49). The three equations underestimated the GFR. Using the Bland-Altman graphic, we observed that the CKD-EPI was the least scattered and most precise; however, mean bias and the interval range (limits of agreement) of all formulas were too big to assume equivalence between 24-hour urinary CrCl method and eGFR based on creatinine. Results of mean bias were similar when comparing the three equations in patients with CrCl GFR <60. However, the accuracy of all formulas was better for the female group and the youngest individuals (≤40 years old).

Conclusion

In this PLKD cohort, of all the three equations, the CKD-EPI was the least scattered and most precise. However, the correlation and the level of agreement between the three equations and 24-hour urinary CrCl were too low to assume the equivalence.

Prognostic Implication of Admission Mean and Pulse Pressure in Acute Decompensated Heart Failure With Different Phenotypes

BACKGROUND

It remains unknown whether admission mean (MAP) and pulse pressure (PP) pressure are associated with short- and long-term mortality in Chinese patients with heart failure with preserved (HFpEF), mid-range (HFmrEF), and reduced (HFrEF) ejection fraction.

METHODS

In 2,706 acute decompensated heart failure (HF) patients, we assessed the risk of 30-day, 1-year, and long-term (>1 year) mortality with 1-SD increment in MAP and PP, using multivariable logistic and Cox regression, respectively.

RESULTS

During a median follow-up of 4.1 years, 1,341 patients died. The 30-day, 1-year, and long-term mortality were 3.5%, 16.7%, and 39.4%, respectively. A lower MAP was associated with a higher risk of 30-day mortality in women (P = 0.023) and a higher risk of 30-day and 1-year mortality in men (P ≤ 0.006), while higher PP predicted long-term mortality in men (P ≤ 0.014) with no relationship observed in women. In adjusted analyses additionally accounted for PP, 1-SD increment in MAP was associated with 30-day mortality in HFpEF (odds ratio [OR], 0.63; 95% CI, 0.43 to 0.92; P = 0.018), with 1-year mortality in HFmrEF (OR, 0.46; 95% CI, 0.32 to 0.66; P < 0.001) and HFrEF (OR, 0.54; 95% CI, 0.40 to 0.72; P < 0.001). In the adjusted model additionally accounted for MAP, 1-SD increment in PP was associated with long-term mortality in HFpEF (hazard ratio, 1.16; 95% CI, 1.05 to 1.28; P = 0.003).

CONCLUSIONS

A lower MAP was associated with a higher risk of short-term mortality in all HF subtypes, while a higher PP predicted a higher risk of long-term mortality in men and in HFpEF. Our observations highlight the clinical importance of admission blood pressure for risk stratification in HF subtypes.

Improved equations to estimate GFR in Chinese children with chronic kidney disease

BACKGROUND

There is currently no specific equation for estimating glomerular filtration rate (GFR) in Chinese children with chronic kidney disease (CKD). The commonly used equations are less robust than expected; we therefore sought to derive more appropriate equations for GFR estimation.

METHODS

A total of 751 Chinese children with CKD were divided into 2 groups, training group (n = 501) and validation group (n = 250). In the training group, a univariate linear regression model was used to calculate predictability of variables associated with GFR. Residuals were compared to determine multivariate predictability of GFR in the equation. Standard regression techniques for Gaussian data were used to determine coefficients of GFR-estimating equations after logarithmic transformation of measured GFR (iGFR), height/serum creatinine (height/Scr), cystatin C, blood urea nitrogen (BUN), and height. These were compared with other well-known equations using the validation group.

RESULTS

Median ^99mTc-DTPA GFR was 90.1 (interquartile range: 67.3-108.6) mL/min/1.73 m² in training dataset. Our CKD equation, eGFR (mL/min/1.73 m²) = 91.021 [height(m)/Scr(mg/dL)/2.7]^0.443 [1.2/Cystatin C(mg/L)]^0.335 [13.7/BUN (mg/dL)]^-0.095 [ 0.991^male] [height(m)/1.4]^0.275, was derived. This was further tested in the validation group, with percentages of eGFR values within 30% and 15% of iGFR (P30 and P15) of 76.00% and 48.40%, respectively. For centres with no access to cystatin C, a creatinine-based equation, eGFR (mL/min/1.73 m²) = 89.674 [height(m)/Scr(mg/dL)/2.7]^0.579 [ 1.007^male] [height(m)/1.4]^0.187, was derived, with P30 and P15 73.60% and 49.20%, respectively. These were significantly higher compared to other well-known equations (p < 0.05).

CONCLUSION

We developed equations for GFR estimation in Chinese children with CKD based on Scr, BUN and cystatin C. These are more accurate than commonly used equations in this population.

Association of Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio with Diabetic Kidney Disease in Chinese Patients with Type 2 Diabetes: A Cross-Sectional Study

Purpose

The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been extensively studied in a variety of diseases. However, research on their relationship with diabetic kidney disease (DKD) is limited. The aim of our study was to investigate the association between these two indicators and renal function in Chinese patients with type 2 diabetes and assess whether they can serve as predictors of DKD.

Methods

This cross-sectional study enrolled 655 Chinese patients with type 2 diabetes. Subjects were divided into three groups according to the urinary albumin-to-creatinine ratio (UACR). The differences in the NLR and PLR among the groups and their correlation with renal function were analyzed. Logistic regression analysis was used to analyze independent risk factors for DKD, and receiver operating characteristic (ROC) curves were used to assess the predictive values of the NLR and PLR for the disease.

Results

The NLR and PLR were significantly different among the three groups, and they increased with increasing levels of albuminuria. Pearson's correlation analysis showed that the NLR and PLR were positively correlated with the UACR but negatively correlated with the estimated glomerular filtration rate (eGFR) (p<0.001). Logistic regression analysis showed that these two indicators were independent risk factors for DKD (p<0.001). The results of ROC curve analysis suggested that the NLR (AUC=0.794; 95% CI, 0.760-0.827; p<0.001) and PLR (AUC=0.665; 95% CI, 0.623-0.706, p<0.001) had important diagnostic value for DKD.

Conclusion

The NLR and PLR were closely associated with renal function among Chinese patients with type 2 diabetes, and high NLR and PLR values may serve as predictors of DKD.

Associations of short- and long-term mortality with admission blood pressure in Chinese patients with different heart failure subtypes

It remains unknown whether systolic (SBP) and diastolic (DBP) pressure on admission are associated with short- and long-term mortality in Chinese patients with heart failure with preserved (HFpEF), mildly reduced (HFmrEF), and reduced (HFrEF) ejection fraction. In 2706 HF patients (39.1% women; mean age, 68.8 years), we assessed the risk of 30-day, 1-year, and long-term (> 1 year) mortality with 1-SD increment in SBP and DBP, using multivariable logistic and Cox regression, respectively. During a median follow-up of 4.1 years, 1341 patients died. The 30-day, 1-year, and long-term mortality were 3.5%, 16.7%, and 39.4%, respectively. In multivariable-adjusted analyses additionally accounted for DBP or SBP, a higher SBP conferred a higher risk of long-term mortality (hazard ratio, 1.11; 95% CI, 1.02-1.22; p = .017) and a lower DBP was associated with a higher risk of all types of mortality (p ≤ .011) in all HF patients. Independent of potential confounders including DBP or SBP, in patients with HFpEF, higher SBP and lower DBP levels predicted a higher risk of long-term mortality with hazard ratios amounting to 1.16 (95% CI, 1.04-1.29; p = .007) and .89 (95% CI, .80-.99; p = .028), respectively. In patients with HFmrEF and HFrEF, irrespective of adjustments of potential confounders, DBP was associated with 1-year mortality with odds ratios ranging from .49 to .62 (p ≤ .006). In conclusion, lower DBP and higher SBP levels on admission were associated with a higher risk of different types of all-cause mortality in Chinese patients with different HF subtypes. Our observations highlight that admission BP may help to improve risk stratification.

The ensemble learning model is not better than the Asian modified CKD-EPI equation for glomerular filtration rate estimation in Chinese CKD patients in the external validation study

OBJECTIVE

To assess the clinical practicability of the ensemble learning model established by Liu et al. in estimating glomerular filtration rate (GFR) and validate whether it is a better model than the Asian modified Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in a cohort of Chinese chronic kidney disease (CKD) patients in an external validation study.

METHODS

According to the ensemble learning model and the Asian modified CKD-EPI equation, we calculated estimated GFRensemble and GFRCKD-EPI, separately. Diagnostic performance of the two models was assessed and compared by correlation coefficient, regression equation, Bland-Altman analysis, bias, precision and P30 under the premise of 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) dual plasma sample clearance method as reference method for GFR measurement (mGFR).

RESULTS

A total of 158 Chinese CKD patients were included in our external validation study. The GFRensemble was highly related with mGFR, with the correlation coefficient of 0.94. However, regression equation of GFRensemble = 0.66*mGFR + 23.05, the regression coefficient was far away from one, and the intercept was wide. Compared with the Asian modified CKD-EPI equation, the diagnostic performance of the ensemble learning model also demonstrated a wider 95% limit of agreement in Bland-Altman analysis (52.6 vs 42.4 ml/min/1.73 m2), a poorer bias (8.0 vs 1.0 ml/min/1.73 m2, P = 0.02), an inferior precision (18.4 vs 12.7 ml/min/1.73 m2, P < 0.001) and a lower P30 (58.9% vs 74.1%, P < 0.001).

CONCLUSIONS

Our study showed that the ensemble learning model cannot replace the Asian modified CKD-EPI equation for the first choice for GFR estimation in overall Chinese CKD patients.

Performance of the CKD-EPI and MDRD equations for estimating glomerular filtration rate: a systematic review of Latin American studies

BACKGROUND

The most-used equations for estimating the glomerular filtration rate (GFR) are the CKD Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations. However, it is unclear which of these shows better performance in Latin America.

OBJECTIVE

To assess the performance of two equations for estimated GFR (eGFR) in Latin American countries.

DESIGN AND SETTING

Systematic review and meta-analysis in Latin American countries.

METHODS

We searched in three databases to identify studies that reported eGFR using both equations and compared them with measured GFR (mGFR) using exogenous filtration markers, among adults in Latin American countries. We performed meta-analyses on P30, bias (using mean difference [MD] and 95% confidence intervals [95% CI]), sensitivity and specificity; and evaluated the certainty of evidence using the GRADE methodology.

RESULTS

We included 12 papers, and meta-analyzed six (five from Brazil and one from Mexico). Meta-analyses that compared CKD-EPI using creatinine measured with calibration traceable to isotope dilution mass spectrometry (CKD-EPI-Cr IDMS) and using MDRD-4 IDMS did not show differences in bias (MD: 0.55 ml/min/1.73m2; 95% CI: -3.34 to 4.43), P30 (MD: 4%; 95% CI: -2% to 11%), sensitivity (76% and 75%) and specificity (91% and 89%), with very low certainty of evidence for bias and P30, and low certainty of evidence for sensitivity and specificity.

CONCLUSION

We found that the performances of CKD-EPI-Cr IDMS and MDRD-4 IDMS did not differ significantly. However, since most of the meta-analyzed studies were from Brazil, the results cannot be extrapolated to other Latin American countries.

REGISTRATION

PROSPERO (CRD42019123434) - https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019123434.

Altered Emotional Phenotypes in Chronic Kidney Disease Following 5/6 Nephrectomy

Increased prevalence of chronic kidney disease (CKD) and neurological disorders including cerebrovascular disease, cognitive impairment, peripheral neuropathy, and dysfunction of central nervous system have been reported during the natural history of CKD. Psychological distress and depression are serious concerns in patients with CKD. However, the relevance of CKD due to decline in renal function and the pathophysiology of emotional deterioration is not clear. Male Sprague Dawley rats were divided into three groups: sham control, 5/6 nephrectomy at 4 weeks, and 5/6 nephrectomy at 10 weeks. Behavior tests, local field potentials, and histology and laboratory tests were conducted and investigated. We provided direct evidence showing that CKD rat models exhibited anxiogenic behaviors and depression-like phenotypes, along with altered hippocampal neural oscillations at 1–12 Hz. We generated CKD rat models by performing 5/6 nephrectomy, and identified higher level of serum creatinine and blood urea nitrogen (BUN) in CKD rats than in wild-type, depending on time. In addition, the level of α-smooth muscle actin (α-SMA) and collagen I for renal tissue was markedly elevated, with worsening fibrosis due to renal failures. The level of anxiety and depression-like behaviors increased in the 10-week CKD rat models compared with the 4-week rat models. In the recording of local field potentials, the power of delta (1–4 Hz), theta (4–7 Hz), and alpha rhythm (7–12 Hz) was significantly increased in the hippocampus of CKD rats compared with wild-type rats. Together, our findings indicated that anxiogenic behaviors and depression can be induced by CKD, and these abnormal symptoms can be worsened as the onset of CKD was prolonged. In conclusion, our results show that the hippocampus is vulnerable to uremia.

Serum uric acid variability increases the risk of postoperative chronic kidney disease in patients with renal cell carcinoma after radical nephrectomy

OBJECTIVE

Serum uric acid (SUA) level is associated with the progression of chronic kidney disease (CKD). However, little is known about the predictive value of SUA variability for postoperative CKD in patients with renal cell carcinoma after radical nephrectomy. We aimed to investigate the association of SUA variability with postoperative CKD in this population.

METHOD

85 patients with preoperative estimated glomerular filtration rate (eGFR)≥60 ml/min/1.73 m² were enrolled in this single-center retrospective study and followed up for at least 6 months. Intra-individual SUA variability was defined as the standard deviation (SD) of SUA and the patients were stratified into three groups according to the tertiles of SUA SD (the lower, middle and upper tertile). The association of SUA variability with postoperative CKD, defined as an eGFR<60 ml/min/1.73m², was analyzed by Cox proportional hazard models and Kaplan-Meier analyses.

RESULTS

After a median follow-up time of 24(10-43) months, 44(51.7%) patients developed postoperative CKD. Kaplan-Meier curves showed that patients in the lower tertile had a longer CKD-free survival time [median CKD-free survival time 74(52.2-95.8) months] than those in the middle tertile [38(19.2-56.8) months] and upper tertile [21(17.9-24.1) months] (overall generalized Wilcoxon test: P=0.001; lower vs middle tertile: P=0.001; lower vs upper tertile: P<0.001). Adjusted Cox analyses indicated that increasing SUA SD tertiles were associated with a higher risk of postoperative CKD independent of baseline SUA, mean SUA during follow-up and other confounding variables. Compared with patients in the lower tertile, the risk for developing CKD increased by 4.6-fold for patients in the middle tertile and 7.9-fold in the upper tertile, respectively.

CONCLUSION

Increasing SUA variability was associated with an increased risk of postoperative CKD in patients with renal cell carcinoma after radical nephrectomy.

Febuxostat is superior to allopurinol in delaying the progression of renal impairment in patients with chronic kidney disease and hyperuricemia

PURPOSE

This study aimed to compare efficacy of renal-protective function between febuxostat and allopurinol in patients with chronic kidney disease (CKD) and hyperuricemia (HUA).

METHODS

Totally 152 CKD stage 2-3 patients complicated with HUA were recruited. According to their uric acid-lowering therapy, there were 67 patients included in febuxostat group and 85 in allopurinol group, respectively. Estimated glomerular filtration rate (eGFR), serum creatinine (Scr), 24-h proteinuria, serum uric acid (SUA) were measured at M0, M1, M3 and M6 after the treatment. Primary outcome was proportion of patients showing ≥ 10% decline in eGFR from baseline at M6.

RESULTS

The eGFR at M6 was numerically higher at M6 and eGFR change (M6-M0) was increased in febuxostat group compared with allopurinol group. Most importantly, the proportion of patients showing a ≥ 10% decline in eGFR from baseline at M6 was reduced in febuxostat group compared with allopurinol group. Multivariate logistic regression analyses further validated that febuxostat vs. allopurinol was an independent predictor for reduced risk of eGFR decline ≥ 10% from baseline. Besides, SUA change (M6-M0) was decreased, but Scr change (M6-M0) and 24-h proteinuria change (M6-M0) were similar in febuxostat group compared with allopurinol group.

CONCLUSIONS

Febuxostat presents a superior effect in delaying renal impairment progression compared with allopurinol in CKD patients complicated with HUA.

A collaborative, individual-level analysis compared longitudinal outcomes across the International Network of Chronic Kidney Disease (iNETCKD) cohorts

Rates of chronic kidney disease (CKD) progression, end stage kidney disease (ESKD), all-cause mortality, and cardiovascular (CVD) events among individuals with CKD vary widely across countries. Well-characterized demographic, comorbidity, and laboratory markers captured for prospective cohorts may explain, in part, such differences. To investigate whether core characteristics of individuals with CKD explain differences in rates of outcomes, we conducted an individual-level analysis of eight studies that are part of iNET-CKD, an international network of CKD cohort studies. Overall, the rate of CKD progression was 40 events/1000 person-year (95% confidence interval 39 - 41), 28 (27 - 29) for ESKD, 41 (40 - 42) for death, and 29 (28 - 30) for CVD events. However, standardized rates were highly heterogeneous across studies (over 92.5%). Interactions by study group on the association between baseline characteristics and outcomes were then identified. For example, the adjusted hazard ratio for CKD progression was 0.44 (95% confidence interval 0.35 - 0.56) for women vs. men among the Japanese (CKD-JAC), while it was 0.66 (0.59 - 0.75) among the Uruguayan (NRHP). The adjusted hazard ratio for ESKD was 2.02 (95% CI 1.88 - 2.17) per 10 units lower baseline eGFR among Americans (CRIC), while it was 3.01 (2.57 - 3.53) among Canadians (CanPREDDICT) (significant interaction for comparisons across all studies). The risks of CKD progression, ESKD, death, and CVD vary across countries even after accounting for the distributions of age, sex, comorbidities, and laboratory markers. Thus, our findings support the need for a better understanding of specific factors in different populations that explain this variation.

Chronic kidney disease in patients at high risk of cardiovascular disease in the United Arab Emirates: A population-based study

Chronic kidney disease has become an increasingly significant clinical and public health issue, accounting for 1.1 million deaths worldwide. Information on the epidemiology of chronic kidney disease and associated risk factors is limited in the United Arab Emirates. Therefore, this study aimed to evaluate the incidence and causes of chronic kidney disease stages 3-5 in adult United Arab Emirates nationals with or at high risk of cardiovascular disease. This retrospective study included 491 adults with or at high risk of cardiovascular disease (diabetes mellitus or associated clinical disease) who attended outpatient clinics at a tertiary care hospital in Al-Ain, United Arab Emirates. Estimated glomerular filtration rate was assessed every 3 months from baseline to June 30, 2017. Chronic kidney disease stages 3-5 were defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2 for ≥ 3 months. Multivariable Cox's proportional hazards analysis was used to determine the independent risk factors associated with developing chronic kidney disease stages 3-5. The cumulative incidence of chronic kidney disease stages 3-5 over a 9-year period was 11.4% (95% confidence interval 8.6, 14.0). The incidence rate of these disease stages was 164.8 (95% confidence interval 121.6, 207.9) per 10,000 person-years. The independent risk factors for developing chronic kidney disease stages 3-5 were older age, history of coronary heart disease, history of diabetes mellitus, and history of smoking. These data may be useful to develop effective strategies to prevent chronic kidney disease development in high-risk United Arab Emirates nationals.

SUDOSCAN, an effective tool for screening chronic kidney disease in patients with type 2 diabetes

SUDOSCAN is a non-invasive method of measuring peripheral small fiber and autonomic nerve activity by detection of abnormal sweat gland function through electrochemical skin conductance. It has been reported to be an effective screening tool in early detection of microvascular type 2 diabetes mellitus (T2DM) complications including diabetic neuropathy and nephropathy in recent studies. However, previous studies used estimated glomerular filtration rate (eGFR) as the golden standard, which has a 90% chance of being within 30% of the measured GFR at best. No relevant study has been performed in the Chinese population concerning SUDOSCAN in the screening of diabetic nephropathy (DN) in comparison with GFR. In this cross-sectional study, SUDOSCAN was performed in 176 Chinese patients with T2DM between September 2014 and September 2015. It was found that the SUDOSCAN test had a sensitivity of 57.8% and a specificity of 100% to detect chronic kidney disease at a cut-off SUDOSCAN-DN score of 59.5. The area under receiver operating characteristic curve for DN was 0.85 [95% confidence interval (CI), 0.76-0.93] compared with 0.84 for eGFR_MDRD (MDRD, modification of diet in renal disease; 95% CI, 0.71-0.98) and 0.77 for eGFR_EPI (EPI, epidemiology collaboration; 95% CI, 0.68-0.87). Patients with DN score <59.5 had a significantly lower GFR level (P<0.001) and significantly older age (P<0.001), longer duration of T2DM (P<0.001) and higher risk of diabetic complications, including diabetic neuropathy (P<0.001) and peripheral vascular disease (P<0.05). These results suggested that SUDOSCAN may be useful for detecting patients at risk of impaired renal function as part of a screening program in the Chinese population with T2DM.