Serum albumin-adjusted glycated albumin reflects glycemic excursion in diabetic patients with severe chronic kidney disease not treated with dialysis

Glycated Albumin and Adverse Clinical Outcomes in Patients With CKD: A Prospective Cohort Study

RATIONALE & OBJECTIVE

Hemoglobin A1c (HbA1c) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,110 participants with CKD from the Chronic Renal Insufficiency Cohort study.

EXPOSURE

Baseline GA levels.

OUTCOME

Incident end-stage kidney disease (ESKD), cardiovascular disease (CVD) events, and all-cause mortality.

ANALYTICAL APPROACH

Cox proportional hazards regression.

RESULTS

Participant characteristics included mean age 59.0±10.8 SD years; 1,357 (43.6%) female; and 1,550 (49.8%) with diabetes. The median GA was 18.7% (IQR, 15.8%-23.3%). During an average 7.9-year follow-up, there were 980 ESKD events, 968 CVD events, and 1,084 deaths. Higher GA levels were associated with greater risks of all outcomes, regardless of diabetes status: hazard ratios for ESKD, CVD, and death among participants with the highest quartile compared with quartile 2 (reference) were 1.42 (95% CI, 1.19-1.69), 1.67 (95% CI, 1.39-2.01), and 1.63 (95% CI, 1.37-1.94), respectively. The associations with CVD and death appeared J-shaped, with increased risk also seen at the lowest GA levels. Among patients with coexisting CKD and diabetes, the associations of GA with outcomes remained significant even after adjusting for HbA1c. For each outcome, we observed a significant increase in the fraction of new prognostic information when both GA and HbA1c were added to models.

LIMITATIONS

Lack of longitudinal GA measurements; and HbA1c measurements were largely unavailable in participants without diabetes.

CONCLUSIONS

Among patients with CKD, GA levels were independently associated with risks of ESKD, CVD, and mortality, regardless of diabetes status. GA added prognostic value to HbA1c among patients with coexisting CKD and diabetes.

PLAIN-LANGUAGE SUMMARY

Hemoglobin A1c (HbA1c) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown. In this cohort study of 3,110 individuals with non-dialysis-dependent CKD, GA levels were independently associated with risks of end-stage kidney disease, cardiovascular disease (CVD), and mortality. The associations with CVD and mortality appeared to be J-shaped. Among patients with coexisting CKD and diabetes, GA added prognostic value to HbA1c. Thus, GA may be a valuable complementary test to HbA1c in patients with CKD.

Serum glycated albumin as a predictive biomarker for renal involvement of antineutrophil cytoplasmic antibody-associated vasculitis in non-diabetic patients

Background

Glycated albumin (GA) is known to reflect the current inflammatory burden in non-diabetes mellitus (DM) patients. In this study, we investigated whether GA at diagnosis could reflect the cross-sectional activity and predict poor outcomes during follow-up in non-DM patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

Methods

The medical records of 118 immunosuppressive drug-naïve AAV patients were retrospectively reviewed, and 76 patients who had both GA and glycated haemoglobin (HbA1c) results but not DM were included in this study. Demographic, clinical, and laboratory data at diagnosis were assessed.

Results

The median age of AAV patients was 61 years, and 31 patients were male. GA was positively correlated with five-factor score (r = 0.282), Birmingham vasculitis activity score (BVAS) assigned to renal manifestation (r = 0.315), and blood urea nitrogen (r = 0.382), whereas negatively correlated with haemoglobin (r = -0.345). AAV patients with end-stage renal disease (ESRD) exhibited significantly higher GA than those without ESRD (15.8% vs. 13.6%). When the cut-off of GA at diagnosis for ESRD was set at GA ≥ 14.25%, AAV patients with GA ≥ 14.25% had a significantly higher risk for ESRD development than those without (relative risk 12.040). In addition, AAV patients with GA ≥ 14.25% exhibited significantly lower cumulative ESRD-free survival rates than those without (P = 0.020).

Conclusion

In conclusion, GA at diagnosis can reflect the cross-sectional BVAS assigned to renal manifestation of AAV and predict ESRD development during follow-up better than HbA1c or GA/HbA1c in AAV patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02913-5.

Assessment of glycemia in chronic kidney disease

Reliable assessment of glycemia is central to the management of diabetes. The kidneys play a vital role in maintaining glucose homeostasis through glucose filtration, reabsorption, consumption, and generation. This review article highlights the role of the kidneys in glucose metabolism and discusses the benefits, pitfalls, and evidence behind the glycemic markers in patients with chronic kidney disease. We specifically highlight the role of continuous glucose monitoring as an emerging minimally invasive technique for glycemic assessment.

Predictive value of the glycated albumin versus glycosylated hemoglobin in follow-up of glucose homeostasis in hemodialysis-maintained type-2 diabetic patients

Objectives. Markers for glucose control in hemodialysis patients (HDP) are debated. Glycosylated hemoglobin (HbA1c%) relies on the stable red blood cell survival. Albumin turnover is faster than hemoglobin. Glycated albumin (GA%) may be used as an index of short-term glycemic control. The predictive value of GA% versus HbA1c% in monitoring the glucose homeostasis in type-2 diabetic HDP is studied. Methods. Forty type-2 diabetic HDP and 20 healthy non diabetic subjects matched age and sex as a control group were included. Calculation of body mass index and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and urea reduction ratio were done. Glycosylated hemoglobin, glycated albumin, fasting blood glucose, insulin, total lipid, kidney and liver functions tests, hepatitis markers, electrolytes, complete blood count, and international normalized ratio were performed. Patients were followed up after 6 months. Results. The study showed that GA% is more sensitive than HbA1c%, but less specific in the follow-up of the glucose homeostasis in type-2 diabetic HDP. Diagnostic accuracy is higher in HbA1c% than in GA%. HOMA-IR is superior regarding the sensitivity and the diagnostic accuracy. Conclusion. The present data show that GA% is more sensitive than HbA1c% and has more diagnostic accuracy in the follow-up of the glucose homeostasis in type-2 diabetic HDP.

Serum glycated albumin predicts all-cause mortality in dialysis patients with diabetes mellitus: meta-analysis and systematic review of a predictive biomarker

BACKGROUND AND AIM

HbA1c, the traditional and current gold standard biomarker guiding diabetic management, has been scrutinized for low predictive value for patients with chronic kidney disease due to variables affecting erythrocyte number and turnover. Glycated albumin, the precursor to advanced glycation end products, reflects glycemic status over the preceding 2-3 week period and already outperforms HbA1c for glycemic monitoring. Our aim was to establish whether serum GA can be further used to predict mortality risk in dialysis patients with diabetes mellitus (DM) METHODS: We did systematic review of the literature in PubMed/Medline, Web of Science, Embase (Elsevier) and the Cochrane Central Register of Controlled Trials (Wiley) up to and including February 2020.

RESULTS

This meta-analysis included 25,932 dialysis patients across 12 studies with maximum follow-up of 11 years. Higher GA levels were associated with the risk of all-cause mortality in dialysis patients with DM (HR 1.02, 95% CI 1.01 to 1.03, P < 0.001) irrespective of the type of dialysis, whereas higher GA was not associated with cardiovascular mortality (HR 1.03, 95% CI 0.99 to 1.06, P = 0.15) and cardiovascular events (both fatal and non-fatal) (HR 1.03, 95% CI 0.97 to 1.09, P = 0.31) in dialysis patients with DM.

CONCLUSION

Serum glycated albumin predicts all-cause mortality risk in dialysis patients with DM. The endpoints of cardiovascular mortality and cardiovascular events trended similarly, but did not reach significance at the current sample size.

Glycemic Monitoring and Management in Advanced Chronic Kidney Disease

Glucose and insulin metabolism in patients with diabetes are profoundly altered by advanced chronic kidney disease (CKD). Risk of hypoglycemia is increased by failure of kidney gluconeogenesis, impaired insulin clearance by the kidney, defective insulin degradation due to uremia, increased erythrocyte glucose uptake during hemodialysis, impaired counterregulatory hormone responses (cortisol, growth hormone), nutritional deprivation, and variability of exposure to oral antihyperglycemic agents and exogenous insulin. Patients with end-stage kidney disease frequently experience wide glycemic excursions, with common occurrences of both hypoglycemia and hyperglycemia. Assessment of glycemia by glycated hemoglobin (HbA1c) is hampered by a variety of CKD-associated conditions that can bias the measure either to the low or high range. Alternative glycemic biomarkers, such as glycated albumin or fructosamine, are not fully validated. Therefore, HbA1c remains the preferred glycemic biomarker despite its limitations. Based on observational data for associations with mortality and risks of hypoglycemia with intensive glycemic control regimens in advanced CKD, an HbA1c range of 7% to 8% appears to be the most favorable. Emerging data on the use of continuous glucose monitoring in this population suggest promise for more precise monitoring and treatment adjustments to permit fine-tuning of glycemic management in patients with diabetes and advanced CKD.

The clinical usefulness of glycated albumin in patients with diabetes and chronic kidney disease: Progress and challenges

Prolonged hyperglycemia leads to a non-enzymatic glycation of proteins, and produces Amadori products, such as glycated albumin (GA) and glycated hemoglobin (HbA1c). The utility of HbA1c in the setting of chronic kidney disease (CKD) may be problematic since altered lifespan of red blood cells, use of iron and/or erythropoietin therapy, uremia and so on. Therefore, as an alternative marker, GA has been suggested as a more reliable and sensitive glycemic index in patients with CKD. In addition to the mean plasma glucose concentration, GA also reflects postprandial plasma glucose and glycemic excursion. Besides, with a half-life of approximately 2-3 weeks, GA may reflect the status of blood glucose more rapidly than HbA1c. GA is also an early precursor of advanced glycation end products (AGEs), which cause alterations in various cellular proteins and organelles. Thus, high GA levels may correlate with adverse outcomes of patients with CKD. In this review, the clinical usefulness of GA was discussed, including a comparison of GA with HbA1c, the utility and limitations of GA as a glycemic index, its potential role in pathogenesis of diabetic nephropathy and the correlations between GA levels and outcomes, specifically in patients with diabetes and CKD.

Glycated Albumin Versus HbA1c in the Evaluation of Glycemic Control in Patients With Diabetes and CKD

INTRODUCTION

It is inaccurate to assess blood glucose with glycated hemoglobin (HbA1c) in patients with diabetes and chronic kidney disease (CKD), and whether glycated albumin (GA) is better than HbA1c in these patients remains unclear.

METHODS

We searched PubMed, Embase, Web of Science, Scopus, the Cochrane Library, and MEDLINE to July 2017 for studies that investigated the correlation between GA or HbA1c and the average glucose levels (AG) relevant to this theme. Statistical analysis was performed using RevMan5.3 and Stata12.0. The outcome was the correlation coefficient between GA or HbA1c and AG. For the first time, we made a comparison of GA and HbA1c in different CKD stages.

RESULTS

A total of 24 studies with 3928 patients were included. Early stages of CKD refer to CKD stage 1 to 3. Advanced CKD refer to CKD stage 4 and 5 including patients receiving dialysis. The meta-analysis suggested that in early stages of CKD, the pooled R between GA and AG was 0.61 (95% CI = 0.49-0.73) and 0.71 (95% CI = 0.55-0.87) for HbA1c (P > 0.05). In advanced CKD patients, the pooled R between GA and AG was 0.57 (95% CI = 0.52-0.62), and 0.49 (95% CI = 0.45-0.52) for HbA1c (P = 0.0001).

CONCLUSION

GA is superior to HbA1c in assessing blood glucose control in diabetes patients with advanced CKD.

Managing Diabetes and Cardiovascular Risk in Chronic Kidney Disease Patients

We discuss mechanisms of increased cardiovascular disease (CVD) in patients with chronic kidney disease (CKD) and strategies for managing cardiovascular (CV) risk in these patients. Our focus was mainly on decreasing CV events and progression of microvascular complications by reducing levels of glucose and lipids. We searched PubMed with no limit on the date of the article. All articles were discussed among all authors. We chose pertinent articles, and searched their references in turn for additional relevant publications.

Definition of the upper reference limit of glycated albumin in blood donors from Italy

BACKGROUND

Glycated Albumin (GA) has been proposed as a short-term indicator of glycemic homeostasis. The aim of this study is to describe the distribution of GA in a large sample of blood donors from Italy to evaluate whether demographic features, namely age and sex, could influence GA levels and define specific reference limits.

METHODS

The study included 1334 Italian blood donors. GA was measured using an enzymatic method (quantILab Glycated Albumin, IL Werfen, Germany). The upper reference limit (URL) was calculated using the non-parametric percentile method.

RESULTS

A modest, although significant, increase of GA was observed in relation to age (p<0.001), especially in males, where the differences were more pronounced (p<0.001 in males, p=0.003 in females). Slight differences were documented based on sex (12% [11.3-12.8] in males; 12.2% [11.4-13.1] in females; p=0.01). After excluding individuals with fasting plasma glucose ≥7 mmol/L, the calculated GA URL was 14.5% (95% CI: 14.3-14.7). Subjects with GA>14.5% presented a mean age of 48.4±12.2 years, 66.7% were males and the mean glucose was 6.88±2.5 mmol/L.

CONCLUSIONS

GA in Caucasians shows a similar increasing trend at older ages documented in other ethnicities. The definition of the URL in this population could be useful for both clinical studies, which will clarify the role of GA for diagnosing and monitoring diabetes, and will encourage the introduction of GA in clinical practice.

Serum albumin-adjusted glycated albumin as a better indicator of glycemic control in Type 2 diabetes mellitus patients with short duration of hemodialysis

AIMS

Serum albumin-adjusted glycated albumin (adjusted GA) is reportedly a better predictor of mortality than GA in patients with Type 2 diabetes mellitus (T2DM) on hemodialysis (HD). We compared how accurately GA and adjusted GA reflected glycemic control in these patients.

METHODS

We enrolled 31 patients with T2DM on HD. They were divided into two groups according to duration of HD: ≤6months (short HD group, N=16) and >6months (long HD group, N=15). GA or adjusted GA and parameters of glycemic control obtained by continuous glucose monitoring were measured, and the correlations between these were analyzed.

RESULTS

GA and adjusted GA were significantly correlated with mean glucose levels (r=0.400, P=0.025 and r=0.508, P=0.0037) in all patients. Similar results were obtained in the long HD group (GA: r=0.554, P=0.032; adjusted GA: r=0.604, P=0.017). However, in the short HD group, adjusted GA (r=0.502, P=0.047) but not GA (r=0.340, P=0.20) was significantly correlated with mean glucose levels.

CONCLUSIONS

Adjusted GA may be a better indicator than GA for evaluating glycemic control in T2DM patients with short duration of HD.

Serum albumin-adjusted glycated albumin is a better predictor of mortality in diabetic patients with end-stage renal disease on hemodialysis

AIMS

Glycated albumin (GA) is a marker for monitoring glycemic control in diabetic patients with end-stage renal disease (ESRD). We evaluated whether serum albumin-adjusted GA (adjusted GA) could predict mortality in diabetic patients with ESRD on hemodialysis.

METHODS

Seventy-eight patients with type 2 diabetes treated with regular hemodialysis were enrolled and followed up for 5-years. The adjusted GA was calculated from the regression formula and mean GA. The cut-off values for GA and adjusted GA that predicted mortality risk were determined using receiver operating characteristic curve analysis.

RESULTS

During the follow-up period (median: 36months), 15 patients died. In the Kaplan-Meier analysis, there were no significant differences in the 5-year cumulative survival rate (58.3% [GA ≥19.8%] vs. 88.6% [GA <19.8%], P=0.075). Conversely, this rate was significantly higher in patients with adjusted GA <21.2% than adjusted GA ≥21.2% (86.4 vs. 49.5%, P=0.0068). After adjustment for other confounders, adjusted GA ≥21.2% was an independent predictor for mortality (hazard ratio 3.76, 95% confidence interval 1.12-17.44, P=0.031), but GA ≥19.8% was not (hazard ratio 2.63, 95% confidence interval 0.65-17.69, P=0.19).

CONCLUSIONS

Adjusted GA is a better predictor of mortality than GA in diabetic patients with ESRD on hemodialysis.