Comparison of two creatinine-based equations for predicting decline in renal function in type 2 diabetic patients with nephropathy in a korean population

Optimal Glomerular Filtration Rate Equations for Various Age Groups, Disease Conditions and Ethnicities in Asia: A Systematic Review

(1) Background: The performance of estimated glomerular filtration rate (eGFR) equations in the Asian population has been widely questioned. The primary objective of this study was to gather evidence regarding optimal GFR equations in Asia for various age groups, disease conditions, and ethnicities. The secondary objective was to see whether the equations based on the combination of creatinine and cystatin C biomarkers if employed are satisfactory across different age groups and disease conditions in various ethnicities in Asia compared to those based on either of the single biomarkers. (2) Methods: Validation studies that had both creatinine and cystatin C-based equations either alone or in combination, validated in specific disease conditions, and those which compared the performance of these equations with exogenous markers were eligible only. The bias, precision, and 30% accuracy (P30) of each equation were recorded accordingly. (3) Results: Twenty-one studies consisting of 11,371 participants were included and 54 equations were extracted. The bias, precision, and P30 accuracies of the equations ranged from -14.54 to 9.96 mL/min/1.73 m², 1.61 to 59.85 mL/min/1.73 m², and 4.7% to 96.10%. The highest values of P30 accuracies were found for the JSN-CKDI equation (96.10%) in Chinese adult renal transplant recipients, for the BIS-2 equation (94.5%) in Chinese elderly CKD patients, and Filler equation (93.70%) also in Chinese adult renal transplant recipients. (4) Conclusions: Optimal equations were identified accordingly and it was proven that combination biomarker equations are more precise and accurate in most of the age groups and disease conditions. These can be considered equations of choice for the specific age groups, disease conditions, and ethnicities within Asia.

Kidney disease burden in an Asian Indian population: Effect of the new 2021 serum creatinine CKD-EPI equation

AIMS

CKD-EPI (chronic kidney disease-epidemiological) serum creatinine equation is widely accepted for calculating estimated glomerular filtration rate (eGFR). The effect of transitioning from the older 2009 to the newer race-independent 2021 CKD-EPI equation on the estimated kidney disease burden (eKDB) was studied in an Asian-Indian population.

METHODS

The study included 1156 adults, the two equations were compared for agreement (Bland-Altman and Cohen's kappa) and concordance (Lin's correlation and test for proportions).

RESULTS

The 2021 CKD-EPI increased the eGFR (positive-bias), independent of age-group, gender or presence of type 2 diabetes mellitus (T2DM) and hypertension (HTN). Thus, the eKDB was significantly decreased by 2021 CKD-EPI equation. The agreement was highest for the age-group 31-40 years (95.8 % versus 87.5 % for > 50 years). Besides, the eGFR category was shifted from G3 to G1 in 8.2 % (95 % CI: 6.8-9.9) individuals by 2021 CKD-EPI. The effect of transition on eKDB was greater in individuals > 50 years (7.4 %) or with HTN (6.3 %).

CONCLUSION

In comparison to the old equation, the 2021 CKD-EPI equation increased the eGFR, lowering the eKDB in this Asian-Indian cohort. The degree of lowering was affected by age-group, and presence of T2DM /HTN, but independent of gender.

Preference between serum homocysteine and urinary periostin as early predictive biomarkers of renal dysfunction among uncontrolled diabetics

OBJECTIVES

Type 2 diabetes mellitus (T2DM) represents a serious public health problem. Environmental toxins, other than infectious agents or exposures can stimulate immune responses which are associated with the occurrence of T2DM. Diabetic nephropathy (DN) is a serious complication of diabetes that leads to changes in the structure and function of the kidneys. The study aimed to detect diagnostic biomarkers for (DN), at an early stage, to prevent disease progression in these patients and improve their outcomes.

METHODS

This study was performed on 102 T2DM patients and 80 normal controls. Blood glucose, HbA_1c, serum homocysteine (Hcy) and urinary periostin were assessed. Patients were divided into: controlled (n=46) (HbA_1c <6.5%) and uncontrolled diabetics (n=56) (HbA_1c >6.5%).

RESULTS

The study results revealed a significant rise in blood glucose and HbA_1c as well as serum Hcy levels in diabetic groups compared to controls. Also, urinary periostin exhibited significant elevation in diabetic groups. Serum glucose, HbA_1c and serum Hcy revealed a highly significant difference between diabetic subgroups and control groups, while urinary periostin demonstrated a non-significant difference. Only, urinary periostin showed a significant increase in uncontrolled diabetics.

CONCLUSIONS

The highest levels of serum Hcy and urinary periostin were recorded only in the uncontrolled diabetics. Urinary periostin was demonstrated as a more preferable biomarker being a non-invasive sample for predicting renal insult in diabetic subjects. This biomarker could be performed regularly for early detection of DN. Also, it could be added to the periodic medical examinations of workers occupationally exposed to workplace pollutants inducing diabetes.

Clinical significance of serum homocysteine as a biomarker for early diagnosis of diabetic nephropathy in type 2 diabetes mellitus patients

Objective

The aim of this study was to investigate the clinical significance of serum homocysteine (Hcy) as a biomarker for early diagnosis of diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) patients.

Methods

Fifty-five T2DM patients with DN and 51 T2DM patients without DN were prospectively recruited from January 2016 to May 2020 in our hospital. The serum Hcy was tested by electrochemiluminescence assay in DN and T2DM groups and compared. The diagnostic efficacy of serum Hcy as a biomarker for early diagnosis of DN was evaluated by calculating the diagnostic sensitivity, specificity and area under the ROC curve (AUC).

Results

The serum levels of Hcy were 15.49 ± 5.40 and 9.23 ± 3.15 μmol/L for DN and T2DM patients, respectively, with statistical difference (t = 7.21, P < 0.001). In the DN group, the serum Hcy levels for patients with hyperfiltration, intermittent proteinuria, microalbuminuria, macroalbuminuria and uremic were 10.99 ± 2.57, 13.90 ± 2.86, 15.38 ± 4.77, 18.98 ± 4.36 and 23.31 ± 5.22 μmol/L, respectively, which indicated that serum Hcy levels in DN were higher than those of T2DM patients and correlated with patient’s renal damage. Using the serum Hcy level as the reference, the diagnostic sensitivity, specificity and AUC were 84.31 (71.41–92.98)%, 74.55 (61.00–85.33)% and 0.85 (0.78–0.92)%, respectively, with the cutoff value of 12.08 between DN and T2DM. The serum Hcy also had relatively good differential diagnostic efficacy between different DN stages with high sensitivity, specificity and AUC.

Conclusion

Serum Hcy was obviously elevated in DN compared to T2MD and correlated with the renal damage severity, which can be applied as a potential serological marker for early diagnosis of DN.

Evaluation of various equations for estimating renal function in elderly Chinese patients with type 2 diabetes mellitus

BACKGROUND

The clinical assessment of kidney function based on the estimated glomerular filtration rate (GFR) in older patients remains controversial. This study evaluated the concordance and feasibility of using various creatinine-based equations for estimating GFR in elderly Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

A cross-sectional analytical study was conducted in 21,723 older diabetic patients (≥60 years) based on electronic health records (EHR) for Minhang District, Shanghai, China. The concordance of chronic kidney disease (CKD) classification among different creatinine-based equations was assessed based on Kappa values, intraclass correlation coefficient (ICC) statistics, and the eGFR agreement between the equations was tested using Bland-Altman plots. The GFR was estimated using the Cockcroft-Gault (CG), Berlin Initiative Study 1 (BIS1), simplified Modification of Diet in Renal Disease (MDRD), MDRD modified for Chinese populations (mMDRD), chronic kidney disease epidemiology collaboration (CKD-EPI), CKD-EPI in Asians (CKD-EPI-Asia), and Ruijin equations.

RESULTS

Overall, the proportion of CKD stages 3-5 (eGFR <60 mL/min/1.73 m²) was calculated as 28.9%, 39.1%, 11.8%, 8.4%, 14.3%, 11.5%, and 12.7% by the eGFR_CG, eGFR_BIS1, eGFR_MDRD, e_GFRmMDRD, e_GFRCKD-EPI, e_{GFRCKD-EPI-Asia}, and e_GFRRuijin equations, respectively. The concordance of albuminuria and decreased eGFR based on the different equations was poor by both the Kappa (<0.2) and ICC (<0.4) statistics. The CKD-EPI-Asia equation resulted in excellent concordance with the CKD-EPI (ICC =0.931), MDRD (ICC =0.963), mMDRD (ICC =0.892), and Ruijin (ICC =0.956) equations for the classification of CKD stages, whereas the BIS1 equation exhibited good concordance with the CG equation (ICC =0.809). In addition, significant differences were observed for CKD stage 1 among all these equations.

CONCLUSION

Accurate GFR values are difficult to estimate using creatinine-based equations in older diabetic patients. Kidney function is complex, and the staff need to be aware of the individualized consideration of other risk factors or markers of reduced renal function in clinical practice.

The Relationship between Increases in Morning Spot Urinary Glucose Excretion and Decreases in HbA1C in Patients with Type 2 Diabetes After Taking an SGLT2 Inhibitor: A Retrospective, Longitudinal Study

INTRODUCTION

Sodium glucose co-transporter 2 (SGLT2) inhibitors increase urinary glucose excretion (UGE) by reducing the renal threshold for glucose excretion, which results in decreased serum glucose concentrations in patients with type 2 diabetes mellitus (T2D). However, no study to date has determined whether larger increases in UGE after SGLT2 inhibitor treatment correspond to larger reductions in glycated hemoglobin (HbA_1C).

METHODS

We enrolled participants who were newly prescribed an SGLT2 inhibitor (dapagliflozin 10 mg or ipragliflozin 50 mg, once daily) as an add-on therapy. Patients were tested for HbA_1C and first morning spot urinary-creatinine and -glucose concentrations immediately prior to administration of the SGLT2 inhibitor and at a 12-week follow-up appointment. We investigated the relationship between increases in morning spot UGE and decreases in HbA_1C.

RESULTS

A total of 101 participants with T2D were enrolled. The median age and diabetes duration were 61.0 and 12.8 years, respectively, and the median HbA_1C was 8.10%. SGLT2 inhibitors significantly lowered the HbA_1C level, with a median change from baseline to week 12 of -0.60% (p < 0.001). Robust increases from baseline were seen for the morning spot urinary glucose-to-creatinine ratio (UGCR), with a median change at week 12 of 47.3 mg/mg. In the correlation analysis, the ∆HbA_1C level showed a significant positive correlation with ∆morning spot UGCR (r = 0.395, p < 0.001). In other words, a greater reduction in HbA_1C was correlated with a smaller increase in UGE. After adjusting for confounding variables, ∆HbA_1C was significantly associated with ∆morning spot UGCR.

CONCLUSIONS

Although SGLT2 inhibitor treatment leads to a reduced HbA_1C level by augmenting UGE, larger increases in UGE do not correlate to larger reductions in HbA_1C. This suggests that the increase in UGE might not be an indicator of the degree of reductions in blood glucose.

The effect of TSH change per year on the risk of incident chronic kidney disease in euthyroid subjects

The objective of this study is to evaluate the predictive values of baseline thyroid-stimulating hormone and the rate of thyroid-stimulating hormone change within the euthyroid state on the development of chronic kidney disease. We conducted a longitudinal study in 17,067 Korean adults with normal thyroid function and no history of thyroid disease. Incident chronic kidney disease was defined as an estimated glomerular filtration rate <60 ml/min/1.73 m². The rate of thyroid-stimulating hormone change was determined by subtracting the baseline thyroid-stimulating hormone level from the thyroid-stimulating hormone level measured at the last visit prior to the diagnosis of chronic kidney disease or at the final visit in subjects without chronic kidney disease, divided by the observation period (years). Subjects were stratified into quintiles according to rates of thyroid-stimulating hormone change. During 86,583 person-years of follow-up (median follow-up 5.2 years), there were 561 incident cases of chronic kidney disease. The risk of incident chronic kidney disease was significantly higher in subjects with rapid increases (quintile 5) or decreases (quintile 1) in thyroid-stimulating hormone levels compared to the reference group (quintile 3). In fully adjusted models, the hazard ratios of quintiles 1 and 5 were 3.15 (95 % confidence interval 2.34 to 4.24; p < 0.001) and 3.37 (95 % confidence interval 2.52 to 4.51; p < 0.001), respectively. However, there was no significant association between baseline thyroid-stimulating hormone and risk of incident chronic kidney disease. The development of chronic kidney disease is associated with the rate of changes in thyroid-stimulating hormone level rather than with baseline thyroid-stimulating hormone levels.

Urinary N-acetyl-β-D-glucosaminidase, an early marker of diabetic kidney disease, might reflect glucose excursion in patients with type 2 diabetes

Recently, several renal tubular damage markers have gained considerable attention because of their clinical implications as sensitive and specific biomarkers for early stage diabetic kidney disease. However, little is known about the demographic and glucometabolic factors affecting levels of urinary N-acetyl-β-D-glucosaminidase (NAG), a marker of proximal tubular damage, in type 2 diabetes mellitus (T2DM).The aim of this study was to investigate the clinical relevance of urinary NAG with regard to demographic and glucometabolic parameters, as well as nephropathic parameters, by comparing the glomerulopathic marker of albuminuria.In this retrospective cross-sectional study, we enrolled a total of 592 patients with either prediabetes (N = 29) or T2DM (N = 563). Glucometabolic parameters (glucose, hemoglobin A1c, glycated albumin [GA], insulin, C-peptide, homeostasis model assessment [HOMA] of insulin resistance, HOMA-β, postprandial C-peptide-to-glucose ratio [PCGR], and urinary glucose-to-creatinine ratio) and nephropathic parameters (urinary NAG, albumin-to-creatinine ratio [ACR], and estimated glomerular filtration rate) were measured.The levels of urinary NAG showed moderate positive correlation with the levels of urinary ACR in T2DM (r = 0.46). In correlation analysis, urinary NAG was more strongly correlated with body mass index (BMI) (r = -0.22; P < 0.001 vs. r = -0.02; P = 0.74), plasma stimulated glucose (r = 0.25; P < 0.001 vs. r = 0.08; P = 0.10), GA (r = 0.20; P < 0.001 vs. r = 0.13; P = 0.01), PCGR (r = -0.17; P = 0.001 vs. r = -0.09; P = 0.11), and HOMA-β (r = -0.10; P = 0.05 vs. r = -0.02; P = 0.79) than urinary ACR. In multiple regression analysis, age, lower BMI, stimulated glucose, GA, and urinary ACR predicted increased urinary NAG.In conclusion, increase in urinary NAG may be related to glycemic parameters reflecting glucose fluctuation and decreased insulin secretory capacity in patients with T2DM. Further longitudinal, prospective studies are needed to investigate a causal relationship between glucose fluctuations, renal tubular damage, and other vascular complications of diabetes.

The Power of Renal Function Estimation Equations for Predicting Long-Term Kidney Graft Survival: A Retrospective Comparison of the Chronic Kidney Disease Epidemiology Collaboration and the Modification of Diet in Renal Disease Study Equations

Evaluation of renal function using an accurate estimation equation is important for predicting long-term graft survival. We designed this retrospective cohort study to evaluate the predictive power of renal function estimation by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease (MDRD) study equations for graft survival. We reviewed data of 3290 adult kidney transplant recipients who underwent transplantation at a single center between April 1979 and September 2012. The reliability and agreement of chronic kidney disease (CKD) stages based on the estimated glomerular filtration rate (eGFR) as calculated by the CKD-EPI and MDRD equations were evaluated using Bland-Altman plots and Cohen weighted kappa analyses. The predictive power of CKD stages as classified by each equation for graft survival was investigated using Cox regression models. Additionally, Pearson and Spearman correlation coefficients were used to reveal the relationship between graft survival and eGFR equations. Of 3290 kidney transplant recipients, 3040 were included in the analysis. The mean follow-up duration was 128.08 ± 83.54 months, and 29.8% of participants were reclassified to higher eGFR categories by the CKD-EPI equation compared to the category classification by the MDRD equation. eGFR calculated using the MDRD equation was underestimated compared to that calculated using the CKD-EPI equation, based on the Bland-Altman plot. In Cohen weighted kappa analysis, agreement across CKD stages classified using the 2 equations was reliable, but all CKD stages classified using the MDRD equation appeared to be in lower eGFR categories than those classified using the CKD-EPI equation. Pearson and Spearman correlation analyses indicated that the CKD stage as classified by the CKD-EPI equation, but not the MDRD equation, was significantly correlated with the risk of graft failure. In multivariable Cox regression analysis for graft failure after adjustment for CKD stage as determined using the MDRD equation, but not the CKD-EPI equation, stage reclassification was significantly associated with a lower graft failure risk. Our data from this long-term follow-up study indicate that the CKD-EPI equation has a stronger predictive power for kidney graft survival than does the MDRD equation in transplantation settings.

Methylmalonic Acid and Homocysteine as Indicators of Vitamin B-12 Deficiency in Cancer

Background/Aims

Normal or high serum vitamin B-12 levels can sometimes be seen in a B-12 deficient state, and can therefore be misleading. High levels of Methymalonic Acid (MMA) and Homocysteine (HC) have been identified as better indicators of B-12 deficiency than the actual serum B-12 level itself. We evaluated the prevalence of vitamin B-12 deficiency using appropriate cut-off levels of vitamin B-12, MMA and HC, and determined the relationship between serum levels of vitamin B-12, MMA and HC in cancer.

Methods

This is a cross-sectional study using a consecutive case series of 316 cancer patients first seen at Cancer Treatment Centers of America^® (CTCA) at Midwestern Regional Medical Center between April 2014 and June 2014. All patients were evaluated at baseline for vitamin B-12 (pg/mL), MMA (nmol/L) and HC (μmol/L) levels. In accordance with previously published research, the following cut-offs were used to define vitamin B-12 deficiency: <300 pg/mL for vitamin B-12, >260 nmol/L for MMA and >12 μmol/L for HC. The relationship between B-12, MMA and HC was evaluated using Spearman's rho correlation coefficient and cross-tabulation analysis. Receiver Operating Characteristic (ROC) curves were estimated using the non-parametric method to further evaluate the diagnostic accuracy of vitamin B-12 using Fedosov quotient as the "gold standard".

Results

Mean age at presentation was 52.5 years. 134 (42.4%) patients were males while 182 (57.6%) were females. Median vitamin B-12, MMA and HC levels were 582.5 pg/mL, 146.5 nmol/L and 8.4 μmol/L respectively. Of 316 patients, 28 (8.9%) were vitamin B-12 deficient based on vitamin B-12 (<300pg/mL), 34 (10.8%) were deficient based on MMA (>260 nmol/L) while 55 (17.4%) were deficient based on HC (>12 μmol/L). Correlation analysis revealed a significant weak negative correlation between vitamin B-12 and MMA (rho = -0.22) as well as B-12 and HC (rho = -0.35). ROC curves suggested MMA to have the best discriminatory power in predicting B-12 deficiency.

Conclusion

Vitamin B-12 is poorly correlated with MMA and HC in cancer. Using serum vitamin B-12 alone to evaluate B-12 status in cancer may fail to identify those with functional deficiency. A thorough clinical assessment is important to identify patients that may have risk factors and/or symptoms suggestive of deficiency. These patients should have additional testing of MMA and HC regardless of their B-12 levels.