Elevated haemoglobin A1c but not fasting plasma glucose conveys risk of chronic kidney disease in non-diabetic individuals

Association between Hemoglobin A1c and Renal Arteriolar Sclerosis in Subjects Presenting without any Apparent Kidney Dysfunction

AIMS

Diabetic kidney disease is a major vascular complication in patients with diabetes mellitus (DM). However, the association between the hemoglobin (Hb)A1c levels, notably the prediabetic levels, and renal pathological changes remains unclear. We investigated the association between the HbA1c levels and renal arteriolar lesions in subjects without any apparent kidney dysfunction using a living kidney donor cohort.

METHODS

Between January 2006 and May 2016, 393 living kidney donors underwent a "zero-time" biopsy at Kyushu University Hospital. The patients were divided into four groups (HbA1c levels ＜5.6%, 5.6%-5.7%, 5.8%-6.4%, and ≥ 6.5%, or diagnosed with DM [DM group]). Renal arteriolar hyalinization and wall thickening were assessed using semi-quantitative grading. We then investigated the association between the HbA1c levels and renal pathological changes.

RESULTS

158 (40.2%) patients had arteriolar hyalinization and 148 (37.6%) showed wall thickening. A significant correlation was observed between the HbA1c levels and wall thickening (p for trend ＜0.001). An elevated HbA1c level was significantly associated with wall thickening according to a multivariable logistic analysis in subjects with HbA1c levels of 5.6%-5.7% and 5.8%-6.4%, and the DM group, compared with those with HbA1c levels of ＜5.6% (odds ratio [OR], 1.91; 95% confidence interval [CI]: [1.03-3.54] for 5.6%-5.7%, OR, 1.96; 95% CI: [1.09-3.53] for 5.8%-6.4%, and OR, 2.86; 95% CI: [0.91-9.01] for the DM group), whereas arteriolar hyalinization did not increase within the nondiabetic HbA1c levels.

CONCLUSIONS

Elevated high-normal HbA1c levels are considered to be independent risk factors for arteriolar wall thickening. Subclinical renal arteriolar sclerosis may develop in patients with prediabetic HbA1c levels.

HbA1c-dependent projection of long-term renal outcomes

BACKGROUND

Diabetes mellitus is a major risk factor for the development of chronic kidney disease (CKD). There is limited data addressing the value of glycated hemoglobin (HbA1c) to predict renal outcomes independent of diabetes status.

METHODS

This single-center retrospective observational study presents data of 19,285 subjects, irrespective of initial CKD or diabetes status. The primary endpoint was defined as the time to manifestation of moderate CKD (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m2 ) in subjects with eGFR ≥60 mL/min/1.73 m2 at baseline. The secondary endpoint was defined as time to progression of CKD (eGFR <30 mL/min/1.73 m2 ) in subjects with eGFR 30-60 mL/min/1.73 m2 . Multivariate time-to-event and logistic regression models were applied to estimate the influences of HbA1c, sex, age, eGFR, triglycerides, and cholesterol on both endpoints.

RESULTS

Lowest baseline HbA1c levels were associated with the slowest decline of kidney function (median time to manifestation of moderate CKD for HbA1c <5.7%: 15.9 years [95% confidence interval (CI): 15.2-16.7]; for HbA1c 5.7%-6.5%: 14.5 years [95% CI: 14.0-15.1]; for HbA1c 6.5%-8.5%: 11.1 years [95% CI: 10.4-11.7]; for HbA1c >8.5%: 8.3 years [95% CI: 7.8-9.2]; p < 0.001). Similar results were observed for the secondary endpoint. Covariate-adjusted time-to-event analysis demonstrated an almost linear correlation between continuous baseline HbA1c levels and the probabilities of reaching both endpoints.

CONCLUSIONS

HbA1c levels are a strong predictor for eGFR decline, irrespective of diabetes status or CKD stage, demonstrating a tight concentration-dependent relationship. This association becomes apparent in the prediabetic HbA1c range and remains constant over the entire HbA1c spectrum.

Diabetes and chronic kidney disease in Chinese adults: a population-based cohort study

INTRODUCTION

Cohort evidence of the association of diabetes mellitus (DM) with chronic kidney disease (CKD) is limited. Previous studies often describe patients with kidney disease and diabetes as diabetic kidney disease (DKD) or CKD, ignoring other subtypes. The present study aimed to assess the prospective association of diabetes status (no diabetes, pre-diabetes, screened diabetes, previously diagnosed controlled/uncontrolled diabetes with/without antidiabetic treatment) and random plasma glucose (RPG) with CKD risk (including CKD subtypes) among Chinese adults.

RESEARCH DESIGN AND METHODS

The present study included 472 545 participants from the China Kadoorie Biobank, using baseline information on diabetes and RPG. The incident CKD and its subtypes were collected through linkage with the national health insurance system during follow-up. Cox regression models were used to calculate the HR and 95% CI.

RESULTS

During 11.8 years of mean follow-up, 5417 adults developed CKD. Screened plus previously diagnosed diabetes was positively associated with CKD (HR=4.52, 95% CI 4.23 to 4.83), DKD (HR=33.85, 95% CI 29.56 to 38.76), and glomerulonephritis (HR=1.66, 95% CI 1.40 to 1.97). In those with previously diagnosed diabetes, participants with uncontrolled diabetes represented higher risks of CKD, DKD, and glomerulonephritis compared with those with controlled RPG. The risk of DKD was found to rise in participants with pre-diabetes and increased with the elevated RPG level, even in those without diabetes.

CONCLUSIONS

Among Chinese adults, diabetes was positively associated with CKD, DKD, and glomerulonephritis. Screen-detected and uncontrolled DM had a high risk of CKD, and pre-diabetes was associated with a greater risk of DKD, highlighting the significance of lifelong glycemic management.

Day-to-Day Blood Pressure Variability and Risk of Incident Chronic Kidney Disease in a General Japanese Population

Background Several longitudinal studies have reported that higher visit-to-visit blood pressure variability is associated with greater risk for developing chronic kidney disease. However, no population-based studies have investigated the association between day-to-day home blood pressure variability and incident chronic kidney disease. Methods and Results A total of 2342 Japanese community-dwelling residents aged ≥40 years without chronic kidney disease at baseline were followed up by annual health examinations for 10 years. Home blood pressure was measured 3 times every morning for 28 days. Day-to-day coefficients of variation of home systolic blood pressure levels were categorized into quintiles. Chronic kidney disease was defined as an estimated glomerular filtration rate <60 mL/min per 1.73 m² or the presence of proteinuria. The hazard ratios for developing chronic kidney disease were estimated with a Cox proportional hazards model. During the follow-up period, 772 participants developed chronic kidney disease. Increased coefficients of variation of home systolic blood pressure were associated significantly with higher risk of chronic kidney disease after adjusting for confounders (P for trend <0.001): Individuals in the highest quintile of coefficients of variation had a 1.50-fold (95% CI, 1.17-1.94) greater risk of developing chronic kidney disease than those in the lowest quintile. The combination of higher coefficients of variation and higher mean value of home systolic blood pressure was associated with the multivariable-adjusted risk of developing chronic kidney disease. Conclusions These findings suggest that increased day-to-day blood pressure variability is a significant risk factor for developing chronic kidney disease in a general Japanese population.

Predictive Value of HbA1c and Metabolic Syndrome for Renal Outcome in Non-Diabetic CKD Stage 1-4 Patients

Glycated hemoglobin (HbA1c) levels are commonly used to indicate long-term glycemic control. An HbA1c level of 6.5−5.7% is defined as pre-diabetes and is proposed as a criterion for diagnosing metabolic syndrome (MetS). However, HbA1c levels can be affected by chronic kidney disease (CKD). Whether HbA1c is associated with clinical outcomes in nondiabetic CKD patients with or without MetS is still unknown. This study included 1270 nondiabetic CKD stage 1−4 Asian patients, divided by HbA1c and MetS. Through linear regression, HbA1c was positively associated with age, waist circumference, hemoglobin levels, and C-reactive protein and was negatively associated with malnutrition−inflammation. HbA1c levels were 5.5% (0.6%) and 5.7% (0.6%) in non-MetS and MetS, respectively (p < 0.001). In Cox regression, higher-level HbA1c was associated with worse composite renal outcome in MetS patients, but with better renal outcome in non-MetS patients: Hazard ratio (HR) (95% confidence interval [CI]) of HbA1c ≥5.7%, compared with HbA1c <5%, was 2.00 (1.06−3.78) in MetS and 0.25 (0.14−0.45) in non-MetS. An association between HbA1c and all-cause mortality was not found. In conclusion, higher HbA1c levels are associated with worse renal outcomes in nondiabetic CKD stage 1−4 patients modified by the presence of MetS.

Renal functional impairment in the elderly, the importance of fasting plasma glucose: the Northern Shanghai Study

BACKGROUND

Chronic kidney disease is a global health problem that is closely related to the aging population. Although plasma glucose levels have been shown to be related to renal dysfunction, risk factors for renal functional impairment in the geriatric population are unknown. The authors therefore aimed to investigate the determinants of renal functional impairment in an elderly population.

METHODS

From June 2014 to August 2015, 912 participants (aged > 65 years) were recruited. Renal function was assessed at baseline; follow-up was conducted in 2016. Within the framework of comprehensive cardiovascular examinations, all conventional cardiovascular risk factors, fasting plasma glucose (FPG), and renal function were assessed. Renal function was evaluated by the estimated glomerular filtration rate (e-GFR) using a modified Modification of Diet in Renal Disease formula. Rapid decline in e-GFR was defined as an e-GFR slope > 5 mL/min per 1.73 m² per year.

RESULTS

We observed that FPG levels were significantly higher in participants with (6.15 ± 2.76 mmol/L) than in those without (5.56 ± 1.61 mmol/L) a rapid decline in e-GFR (p = 0.02). The average decline in e-GFR was 0.149 mL/min/1.73m² per year in this elderly population, and the increasing risk of having rapid decline in e-GFR was 0.44-fold each year. In the full adjustment model, decline in e-GFR (p = 0.02) and rapid decline in e-GFR (OR1.33, 95% CI 1.03-1.72) were significantly associated with FPG, independent of other conventional cardiovascular risk factors. Using the same models, decline in e-GFR (p = 0.04) and rapid decline in e-GFR (OR 1.57, 95% CI 1.05-2.35) were also significantly associated with FPG in diabetic population, but they were not in non-diabetic population.

CONCLUSIONS

In community-dwelling elderly Chinese, the average decline in e-GFR was 0.149 mL/min/1.73m² per year. FPG control is important for delaying renal functional impairment in elderly population. Trial registration NSS, NCT02368938.

Association between obesity and urinary albumin-creatinine ratio in the middle-aged and elderly population of Southern and Northern China: a cross-sectional study

OBJECTIVE

The relationship between obesity and albuminuria has not been clarified. This study aimed to investigate the correlation between obesity and the urinary albumin-creatinine ratio (UACR) in Southern and Northern China.

DESIGN

A descriptive, cross-sectional study.

SETTING

Eight regional centres in REACTION (China's Risk Evaluation of cAncers in Chinese diabeTic Individuals, a lONgitudinal study), including Dalian, Lanzhou, Zhengzhou, Guangzhou, Guangxi, Luzhou, Shanghai and Wuhan.

PARTICIPANTS

A total of 41 085 patients who were not diagnosed with chronic kidney disease (CKD) and had good compliance were selected according to the inclusion criteria. Patients who were diagnosed with CKD, who had other kidney diseases that could lead to increased urinary protein excretion, who were using angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers and whose important data were missing were excluded.

RESULTS

Participants with both, central and peripheral obesity, had a higher risk of elevated UACR, even after adjusting for multiple factors (OR: 1.14, 95% CI: 1.07 to 1.12, p<0.001), and the risk of high UACR in the South was more prominent than that in the North (OR _South: 1.22, 95% CI: 1.11 to 1.34; OR _North: 1.13, 95% CI: 1.04 to 1.22, p<0.001). The risk was also elevated in the male population, hypertensive individuals, glycosylated haemoglobin (HbA1c)≥6.5% and age ≥60 years in the South. Besides the above groups, diabetes was also a risk factor for the Northern population.

CONCLUSIONS

In China, people with both central and peripheral obesity are prone to a high UACR, and the southern population has a higher risk than northern population. Factors such as male sex, hypertension, HbA1c≥6.5% and an age ≥60 years are also risk factors for CKD.

Chronic Microvascular Complications in Prediabetic States-An Overview

A prediabetic state is a major risk factor for the development of diabetes, and, because of an identical pathophysiological background of both conditions, their prevalence increases parallelly and equally fast. Long-term hyperglycemia is the main cause inducing chronic complications of diabetes, yet the range of glucose levels at which they start has not been yet unequivocally determined. The current data show that chronic microvascular complications of diabetes can be observed in patients with abnormal glucose metabolism in whom glycaemia is higher than optimal but below diagnostic criteria for diabetes. Prediabetes is a heterogenous nosological unit in which particular types are differently characterized and show different correlations with particular kinds of complications. Analysis of the latest research results shows the need to continue studies in a larger population and can imply the need to verify the currently employed criteria of diagnosing diabetes and chronic complications of diabetes in people with prediabetes.

Risk of chronic kidney disease defined by decreased estimated glomerular filtration rate in individuals with different prediabetic phenotypes: results from a prospective cohort study in China

OBJECTIVE

We aimed to investigate the effects of prediabetes and its phenotypes of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycated hemoglobin A₁c (EHbA_1c) on chronic kidney disease (CKD) occurrence, and define the cut-off point of each glycemic index that significantly increases the risk of CKD.

RESEARCH DESIGN AND METHODS

In this prospective cohort study, 6446 non-diabetic subjects aged 40 years and over were followed over a period of 3 years to track the new onset of CKD. Cox regression was used to assess the association of prediabetes and its phenotypes with CKD. Receiver operating characteristic curves were used to define the cut-off point of each glycemic index that significantly increases the occurrence of CKD. Population attributable risk percent was calculated to estimate the contribution of prediabetes to CKD.

RESULTS

Compared to subjects with normal glucose tolerance, patients with prediabetes significantly increased the risk of development of CKD (HR=2.33 (1.19-4.55)). Specifically, this increased risk of CKD development was observed in patients with IFG, IGT and EHbA_1c. The cut-off points shown to significantly increase the risk of CKD are fasting plasma glucose of 5.63 mmol/L, 2-hour plasma glucose of 6.80 mmol/L and HbA_1c of 5.6%. The contribution of prediabetes to CKD occurrence in the study population was 60.6%.

CONCLUSIONS

This result suggests that the stricter criteria might be needed to define normal plasma glucose level in China that would not be predisposed to diabetic complications, particularly CKD.

Association between Prediabetes and Renal Dysfunction from a Community-based Prospective Study

Objective: Our study aimed to evaluate the association between prediabetes and renal dysfunction, and further assess which of glycemic indices of fasting plasma glucose (FPG), postprandial plasma glucose (PPG) and hemoglobin A1c (HbA1c) has a higher risk of renal dysfunction. Methods: This was a community-based prospective cohort study, which included 7015 participants from Beijing and Taian between May and October in 2015. The outcome was the renal dysfunction defined as estimated glomerular filtration rate (eGFR)<60 mL/min/1.73 m². Univariate and multivariate logistic regression model was performed, and calculated the odds ratio (OR) and 95% confidence interval (95%CI) of renal dysfunction. Receiver operating curve (ROC) analysis was used to predict renal dysfunction for glycemic indices. Results: 121 renal dysfunction cases were identified. We found that the adjusted ORs (95%CI) of renal dysfunction were 1.72 (1.11-2.38), 1.48 (1.09-1.93), 1.97 (1.27-2.89) and 1.35 (1.07-2.13), respectively, for those with prediabetes, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated HbA1c, compared with individuals with normal glucose tolerance. And IGT presented a higher risk of renal dysfunction than other glycemic indices. The similar results were obtained by performing the subgroup analysis. ROC analysis revealed the PPG had a higher predictive value for renal dysfunction. Conclusion: We found prediabetes was positively associated with the risk of renal dysfunction and PPG had a higher risk and predictive value of renal dysfunction than other glycemic indices of FPG and HbA1c.