Metabolic factors and microinflammatory state promote kidney injury in type 2 diabetes mellitus patients

Diabetes mellitus is a risk factor for incident chronic kidney disease: A nationwide cohort study

Objective

Diabetes mellitus and chronic kidney disease are multifactorial conditions with multiple etiologies that share similar pathophysiologies. This nationwide cohort study examined the impact of diabetes mellitus on the follow-up development of chronic kidney disease.

Methods

By retrieving the Longitudinal Health Insurance Database 2005, 5121 patients with diabetes mellitus were included in this study and 5121 patients without diabetes mellitus, who were matched according to sex, age, and Charlson comorbidity index made up the control group. The adjusted hazard ratios for chronic kidney disease were calculated using Cox proportional hazards regression analysis. Kaplan-Meier analysis was used to estimate the cumulative incidence of chronic kidney disease rate in the diabetes mellitus and control groups.

Results

After adjusting for sex, age, and Charlson comorbidity index score, the diabetes mellitus group had a 1.380 times higher (95% CI: 1.277-1.492) risk of developing chronic kidney disease than the control group. Further stratified analysis showed that patients with diabetes mellitus had a significantly higher risk of developing chronic kidney disease regardless of their sex, age, and Charlson comorbidity index score, compared to those without diabetes mellitus.

Conclusions

There is a possibility that diabetes mellitus serves as an independent risk factor for chronic kidney disease development. Early screening and monitoring of diabetes mellitus appear to be of great importance in the prevention of chronic kidney disease.

Low serum vitamin D concentration is correlated with anemia, microinflammation, and oxidative stress in patients with peritoneal dialysis

BACKGROUND

Peritoneal dialysis (PD) is a form of dialysis to replace the function of kidney, that uses the peritoneum as a dialysis membrane to remove metabolites and water retained in the body. Vitamin D deficiency is prevalent in patients treated with PD. This research investigated the correlation between serum 25-hydroxyvitamin D [25(OH)D] concentration and anemia, microinflammation, and oxidative stress in PD patients.

METHODS

62 PD patients and 56 healthy volunteers were recruited in this research. Serum concentrations of 25(OH)D and basic parameters of anemia were detected. The correlation between serum 25(OH)D concentration with anemia, oxidative stress, and microinflammatory state were analyzed.

RESULTS

In the PD group, the concentration of 25(OH)D was lower than the healthy control (HC) group (p < 0.001). Hemoglobin, red blood cell count (RBC), and total iron binding capacity (TIBC) in the PD group was significantly lower (all p < 0.001), while high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) concentrations were significantly higher, than the HC group (all p < 0.001). In the PD group, malondialdehyde (MDA) concentration was higher than in the HC group (p < 0.001), while superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were lower (both p < 0.001). Serum 25(OH)D exhibited positive correlation with hemoglobin (r = 0.4509, p = 0.0002), RBC (r = 0.3712, p = 0.0030), TIBC (r = 0.4700, p = 0.0001), SOD (r = 0.4992, p < 0.0001) and GSH-Px (r = 0.4312, p = 0.0005), and negative correlation with hs-CRP (r = - 0.4040, p = 0.0011), TNF-α (r = - 0.4721, p = 0.0001), IL-6 (r = - 0.5378, p < 0.0001) and MDA (r = - 0.3056, p = 0.0157).

CONCLUSION

In conclusion, reduced serum 25(OH)D concentrations in PD patients contribute to anemia, oxidative stress and microinflammatory state.

Value of the combined examination of Cys-C and HbA1c for diagnosis of early renal injury in pediatric diabetes

The objective of the present study was to evaluate the combined application of measuring cystatin C (Cys-C) and hemoglobin A1c (HbA1c) levels for early renal injury in pediatric patients with type 2 diabetes. A total of 130 children with type 2 diabetes admitted to our hospital from May 2013 to July 2015 were selected. Patients were divided according to whether there was complication of renal injury. In group A (n=65), the patients had renal injury and in group B (n=65), the patients did not have renal injury. The levels of Cys-C and HbA1c in the two groups were examined. The results showed that the levels of Cys-C and HbA1c of patients in group A were significantly higher than those in group B (P<0.05), and the positive rate of the combined examination of Cys-C and HbA1c in group A was 92.3%, and was higher than that of the individual examinations of either Cys-C or HbA1c (P<0.05). The Spearman's correlation coefficient analysis was applied to group B and showed that Cys-C was positively correlated with HbA1c (r=0.842, P<0.05). From analysis of the receiver operating characteristic curves, the combined examination of Cys-C and HbA1c surpassed the individual examinations of Cys-C or HbA1c in sensitivity and specificity (P<0.05). In conclusion, the positive detection rate of early renal injury was significantly increased by the combined examination of Cys-C and HbA1c in pediatric patients with type 2 diabetes, which is beneficial for early identification and diagnosis of this diseases and is worthy of clinical application.

Effects of CP-900691, a novel peroxisome proliferator-activated receptor α, agonist on diabetic nephropathy in the BTBR ob/ob mouse

Piperidine-based peroxisome proliferator-activated receptor-α agonists are agents that are efficacious in improving lipid, glycemic, and inflammatory indicators in diabetes and obesity. This study sought to determine whether CP-900691 ((S)-3-[3-(1-carboxy-1-methyl-ethoxy)-phenyl]-piperidine-1-carboxylic acid 4-trifluoromethyl-benzyl ester; CP), a member of this novel class of agents, by decreasing plasma triglycerides, could prevent diabetic nephropathy in the Black and Tan, BRachyuric (BTBR) ob/ob mouse model of type 2 diabetes mellitus. Four-week old female BTBR WT and BTBR ob/ob mice received either regular chow or one containing CP (3 mg/kg per day) for 14 weeks. CP elevated plasma high-density lipoprotein, albuminuria, and urinary excretion of 8-epi PGF(2α), a product of the nonenzymatic metabolism of arachidonic acid and whose production is elevated in oxidative stress, in BTBR WT mice. In BTBR ob/ob mice, CP reduced plasma triglycerides and non-esterified fatty acids, fasting blood glucose, body weight, and plasma interleukin-6, while concomitantly improving insulin resistance. Despite these beneficial metabolic effects, CP had no effect on elevated plasma insulin, 8-epi PGF(2α) excretion, and albuminuria, and surprisingly, did not ameliorate the development of diabetic nephropathy, having no effect on the accumulation of renal macrophages, glomerular hypertrophy, and increased mesangial matrix expansion. In addition, CP did not increase plasma high-density lipoprotein in BTBR ob/ob mice, while paradoxically increasing total cholesterol levels. These findings indicate that 8-epi PGF(2α), possibly along with hyperinsulinemia and inflammatory and dysfunctional lipoproteins, is integral to the development of diabetic nephropathy and should be considered as a potential target of therapy in the treatment of diabetic nephropathy.

Association between plasma triglycerides and high-density lipoprotein cholesterol and microvascular kidney disease and retinopathy in type 2 diabetes mellitus: a global case-control study in 13 countries

BACKGROUND

Microvascular renal and retinal diseases are common major complications of type 2 diabetes mellitus. The relation between plasma lipids and microvascular disease is not well established.

METHODS AND RESULTS

The case subjects were 2535 patients with type 2 diabetes mellitus with an average duration of 14 years, 1891 of whom had kidney disease and 1218 with retinopathy. The case subjects were matched for diabetes mellitus duration, age, sex, and low-density lipoprotein cholesterol to 3683 control subjects with type 2 diabetes mellitus who did not have kidney disease or retinopathy. The study was conducted in 24 sites in 13 countries. The primary analysis included kidney disease and retinopathy cases. Matched analysis was performed by use of site-specific conditional logistic regression in multivariable models that adjusted for hemoglobin A1c, hypertension, and statin treatment. Mean low-density lipoprotein cholesterol concentration was 2.3 mmol/L. The microvascular disease odds ratio increased by a factor of 1.16 (95% confidence interval, 1.11-1.22) for every 0.5 mmol/L (≈1 quintile) increase in triglycerides or decreased by a factor of 0.92 (0.88-0.96) for every 0.2 mmol/L (≈1 quintile) increase in high-density lipoprotein cholesterol. For kidney disease, the odds ratio increased by 1.23 (1.16-1.31) with triglycerides and decreased by 0.86 (0.82-0.91) with high-density lipoprotein cholesterol. Retinopathy was associated with triglycerides and high-density lipoprotein cholesterol in matched analysis but not significantly after additional adjustment.

CONCLUSIONS

Diabetic kidney disease is associated worldwide with higher levels of plasma triglycerides and lower levels of high-density lipoprotein cholesterol among patients with good control of low-density lipoprotein cholesterol. Retinopathy was less robustly associated with these lipids. These results strengthen the rationale for studying dyslipidemia treatment to prevent diabetic microvascular disease.

Derivation and validation of a renal risk score for people with type 2 diabetes

OBJECTIVE

Diabetes has become the leading cause of end-stage renal disease (ESRD). Renal risk stratification could assist in earlier identification and targeted prevention. This study aimed to derive risk models to predict ESRD events in type 2 diabetes in primary care.

RESEARCH DESIGN AND METHODS

The nationwide derivation cohort included adults with type 2 diabetes from the New Zealand Diabetes Cohort Study initially assessed during 2000-2006 and followed until December 2010, excluding those with pre-existing ESRD. The outcome was fatal or nonfatal ESRD event (peritoneal dialysis or hemodialysis for ESRD, renal transplantation, or death from ESRD). Risk models were developed using Cox proportional hazards models, and their performance was assessed in a separate validation cohort.

RESULTS

The derivation cohort included 25,736 individuals followed for up to 11 years (180,497 person-years; 86% followed for ≥5 years). At baseline, mean age was 62 years, median diabetes duration 5 years, and median HbA1c 7.2% (55 mmol/mol); 37% had albuminuria; and median estimated glomerular filtration rate (eGFR) was 77 mL/min/1.73 m2. There were 637 ESRD events (2.5%) during follow-up. Models that included sex, ethnicity, age, diabetes duration, albuminuria, serum creatinine, systolic blood pressure, HbA1c, smoking status, and previous cardiovascular disease status performed well with good discrimination and calibration in the derivation cohort and the validation cohort (n=5,877) (C-statistics 0.89-0.92), improving predictive performance compared with previous models.

CONCLUSIONS

These 5-year renal risk models performed very well in two large primary care populations with type 2 diabetes. More accurate risk stratification could facilitate earlier intervention than using eGFR and/or albuminuria alone.

Sex differences in the relationship between leukocyte count and chronic kidney disease: the 2007 Korean National Health and Nutrition Examination Survey

BACKGROUND

Chronic kidney disease (CKD) has emerged as an independent predictor for cardiovascular disease (CVD), which is now regarded as an inflammatory disease. This study aimed to determine the association of CKD with white blood cell (WBC) count as a marker of systemic inflammation.

METHODS

We examined the association of WBC count with CKD in 2825 Korean adults (1155 men, 1670 women) in the 2007 Korean National Health and Nutrition Examination Survey (KNHANES). CKD was defined as either proteinuria or a glomerular filtration rate (GFR) <60 mL/min/1.73 m(2). The odds ratios (ORs) for CKD were calculated using multivariate logistic regression analysis after adjusting for confounding variables across gender-specific WBC count quartiles.

RESULTS

The proportion of CKD increased with increasing WBC quartiles, from 9.7% in the lowest quartile to 20.7% in the highest quartile for women. In multivariate logistic regression analysis, the corresponding odds ratios (95% confidence intervals [CIs]) for a CKD across WBC count quartiles among women were 1.00, 1.45 (0.91-2.31), 1.65 (1.03-2.63), and 2.11 (1.33-3.35), after adjusting for age, body mass index (BMI), systolic blood pressure, fasting plasma glucose, smoking status, current drinking high-density lipoprotein cholesterol (HDL-C), and triglyceride. In contrast, compared with women, men appeared to have no significant results of a relationship between WBC quartiles and CKD.

CONCLUSIONS

Our study shows a significant association between WBC count and the risk for CKD in women. Accordingly, potential health benefits of early detection of a higher level of WBC count may be useful for CKD risk assessment in women.