Genetic and clinical variables identify predictors for chronic kidney disease in type 2 diabetes

Genetic Variants Related to Increased CKD Progression-A Systematic Review

The incidence and prevalence of chronic kidney disease (CKD) are increasing worldwide. CKD is associated with high morbidity, premature mortality, and high healthcare costs. Genetic variants may influence CKD development and progression. This study aimed to identify the associations between allelic variants and CKD progression. We performed a systematic literature review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PubMed, Embase, and Cochrane Central databases were used for data collection. Hereditary causes of CKD were excluded from the analysis. A total of 38 reports were included. The selected studies included cohort studies, case-control studies, and genome-wide association studies (GWASs). The studies involved patients of different ethnicities and with comorbid diseases. Several genetic variants were identified in genes that encode proteins related to metabolic processes, oxidative stress, immune regulation, the renin-angiotensin-aldosterone pathway, and epigenetics, among others. These genetic alterations can affect protein function and lead to renal damage, impacting CKD development and progression. Gene polymorphisms can influence CKD progression. Many of these are population-specific, and their relevance may be influenced by the presence of other diseases and environmental factors. Larger studies are needed to confirm the associations described here.

T2DM/CKD genetic risk scores and the progression of diabetic kidney disease in T2DM subjects

This study aimed at understanding the predictive potential of genetic risk scores (GRS) for diabetic kidney disease (DKD) progression in patients with type 2 diabetes mellitus (T2DM) and Major Cardiovascular Events (MCVE) and All-Cause Mortality (ACM) as secondary outcomes. We evaluated 30 T2DM and CKD GWAS-derived single nucleotide polymorphisms (SNPs) and their association with clinical outcomes in a central European cohort (n = 400 patients). Our univariate Cox analysis revealed significant associations of age, duration of diabetes, diastolic blood pressure, total cholesterol and eGFR with progression of DKD (all P < 0.05). However, no single SNP was conclusively associated with progression to DKD, with only CERS2 and SHROOM3 approaching statistical significance. While a single SNP was associated with MCVE - WSF1 (P = 0.029), several variants were associated with ACM - specifically CANCAS1, CERS2 and C9 (all P < 0.02). Our GRS did not outperform classical clinical factors in predicting progression to DKD, MCVE or ACM. More precisely, we observed an increase only in the area under the curve (AUC) in the model combining genetic and clinical factors compared to the clinical model alone, with values of 0.582 (95 % CI 0.487-0.676) and 0.645 (95 % CI 0.556-0.735), respectively. However, this difference did not reach statistical significance (P = 0.06). This study highlights the complexity of genetic predictors and their interplay with clinical factors in DKD progression. Despite the promise of personalised medicine through genetic markers, our findings suggest that current clinical factors remain paramount in the prediction of DKD. In conclusion, our results indicate that GWAS-derived GRSs for T2DM and CKD do not offer improved predictive ability over traditional clinical factors in the studied Czech T2DM population.

Aberrant proximal tubule DNA methylation underlies phenotypic changes related to kidney dysfunction in patients with diabetes

Epigenetic mechanisms are considered to contribute to diabetic nephropathy by maintaining memory of poor glycemic control during the early stages of diabetes. However, DNA methylation changes in the human kidney are poorly characterized, because of the lack of cell type-specific analysis. We examined DNA methylation in proximal tubules (PTs) purified from patients with diabetic nephropathy and identified differentially methylated CpG sites, given the critical role of proximal tubules in the kidney injury. Hypermethylation was observed at CpG sites annotated to genes responsible for proximal tubule functions, including gluconeogenesis, nicotinamide adenine dinucleotide synthesis, transporters of glucose, water, phosphate, and drugs, in diabetic kidneys, whereas genes involved in oxidative stress and the cytoskeleton exhibited demethylation. Methylation levels of CpG sites annotated to ACTN1, BCAR1, MYH9, UBE4B, AFMID, TRAF2, TXNIP, FOXO3, and HNF4A were correlated with the estimated glomerular filtration rate, whereas methylation of the CpG site in RUNX1 was associated with interstitial fibrosis and tubular atrophy. Hypermethylation of G6PC and HNF4A was accompanied by decreased expression in diabetic kidneys. Proximal tubule-specific hypomethylation of metabolic genes related to HNF4A observed in control kidneys was compromised in diabetic kidneys, suggesting a role for aberrant DNA methylation in the dedifferentiation process. Multiple genes with aberrant DNA methylation in diabetes overlapped genes with altered expressions in maladaptive proximal tubule cells, including transcription factors PPARA and RREB1. In conclusion, DNA methylation derangement in the proximal tubules of patients with diabetes may drive phenotypic changes, characterized by inflammatory and fibrotic features, along with impaired function in metabolism and transport.NEW & NOTEWORTHY Cell type-specific DNA methylation patterns in the human kidney are not known. We examined DNA methylation in proximal tubules of patients with diabetic nephropathy and revealed that oxidative stress, cytoskeleton, and metabolism genes were aberrantly methylated. The results indicate that aberrant DNA methylation in proximal tubules underlies kidney dysfunction in diabetic nephropathy. Aberrant methylation could be a target for reversing memory of poor glycemic control.

Investigating linear and nonlinear associations of LDL cholesterol with incident chronic kidney disease, atherosclerotic cardiovascular disease and all-cause mortality: A prospective and Mendelian randomization study

BACKGROUND AND AIMS

Observational studies suggest potential nonlinear associations of low-density lipoprotein cholesterol (LDL-C) with cardio-renal diseases and mortality, but the causal nature of these associations is unclear. We aimed to determine the shape of causal relationships of LDL-C with incident chronic kidney disease (CKD), atherosclerotic cardiovascular disease (ASCVD) and all-cause mortality, and to evaluate the absolute risk of adverse outcomes contributed by LDL-C itself.

METHODS

Observational analysis and one-sample Mendelian randomization (MR) with linear and nonlinear assumptions were performed using the UK Biobank of >0.3 million participants with no reported prescription of lipid-lowering drugs. Two-sample MR on summary-level data from the Global Lipid Genetics Consortium (N = 296,680) and the CKDGen (N = 625,219) was employed to replicate the relationship for kidney traits. The 10-year probabilities of the outcomes was estimated by integrating the MR and Cox models.

RESULTS

Observationally, participants with low LDL-C were significantly associated with a decreased risk of ASCVD, but an increased risk of CKD and all-cause mortality. Univariable MR showed an inverse total effect of LDL-C on incident CKD (HR [95% CI]:0.84 [0.73-0.96]; p = 0.011), a positive effect on ASCVD (1.41 [1.29-1.53]; p<0.001), and no significant causal effect on all-cause mortality. Multivariable MR, controlling for high-density lipoprotein cholesterol (HDL-C) and triglycerides, identified a positive direct effect on ASCVD (1.32 [1.18-1.47]; p<0.001), but not on CKD and all-cause mortality. These results indicated that genetically predicted low LDL-C had an inverse indirect effect on CKD mediated by HDL-C and triglycerides, which was validated by a two-sample MR analysis using summary-level data from the Global Lipid Genetics Consortium (N = 296,680) and the CKDGen consortium (N = 625,219). Suggestive evidence of a nonlinear causal association between LDL-C and CKD was found. The 10-year probability curve showed that LDL-C concentrations below 3.5 mmol/L were associated with an increased risk of CKD.

CONCLUSIONS

In the general population, lower LDL-C was causally associated with lower risk of ASCVD, but appeared to have a trade-off for an increased risk of CKD, with not much effect on all-cause mortality. LDL-C concentration below 3.5 mmol/L may increase the risk of CKD.

Longitudinal metabolomics integrated with machine learning identifies novel biomarkers of gestational diabetes mellitus

BACKGROUND

Evidence from longitudinal studies is crucial to enhance our understanding of the role of metabolites in the progression of gestational diabetes mellitus (GDM). Herein, a longitudinal untargeted metabolomic study was conducted to reveal the metabolomic profiles and biomarkers associated with the progression of GDM, and characterize the changing patterns of metabolites.

METHODS

We collected serum samples at three trimesters from 30 patients with GDM and 30 healthy Chinese pregnant women with pre-pregnancy BMI, age, and parity matched, and untargeted metabolomic analysis was performed, followed by machine learning approaches that integrated bootstrap and LASSO. Cluster analysis was conducted to elucidate the patterns of metabolite changes. Pathway analyses were conducted to gain insights into the underlying pathways involved.

RESULTS

A total of 32 metabolites, mainly belonging to amino acid and its derivatives, were significantly associated with GDM across three trimesters, and were clustered into three distinct patterns. Metabolites belonging to phosphatidylcholines, lysophosphatidylcholines, lysophosphatidic acids, and lysophosphatidylethanolamines were consistently upregulated, and 2,3-Dihydroxypropyl dihydrogen phosphate was downregulated in GDM group. Amino acid-related, glycerophospholipid, and vitamin B6 metabolism were enriched in multiple trimesters. The levels of allantoic acid, which was positively correlated with blood glucose, was consistently higher in GDM patients and exhibited good discriminatory ability for GDM in the early and mid-pregnancy.

CONCLUSION

We identified and characterized distinct patterns of metabolites associated with GDM throughout pregnancy, and found that allantoic acid was a potential biomarker for early diagnosis of GDM.

Risk prediction of nephropathy by integrating clinical and genetic information among adult patients with type 2 diabetes

AIMS

Diabetic nephropathy (DN) is a major healthcare challenge. We developed and internally and externally validated a risk prediction model of DN by integrating clinical factors and SNPs from genes of multiple CKD-related pathways in the Han Chinese population.

MATERIALS AND METHODS

A total of 1526 patients with type 2 diabetes were randomly allocated into derivation (n = 1019) or validation (n = 507) sets. External validation was performed with 3899 participants from the Taiwan Biobank. We selected 66 SNPs identified from literature review for building our weighted genetic risk score (wGRS). The steps for prediction model development integrating clinical and genetic information were based on the Framingham Heart Study.

RESULTS

The AUROC (95% CI) for this DN prediction model with combined clinical factors and wGRS was 0.81 (0.78, 0.84) in the derivation set. Furthermore, by directly using the information of these 66 SNPs, our final prediction model had AUROC values of 0.85 (0.82, 0.87), 0.89 (0.86, 0.91), and 0.77 (0.74, 0.80) in the derivation, internal validation, and external validation sets, respectively. Under the combined model, the results with a cutoff point of 30% showed 70.91% sensitivity, 67.84% specificity, 51.54% positive predictive value, and 82.86% negative predictive value.

CONCLUSIONS

We developed and internally and externally validated a model with clinical factors and SNPs from genes of multiple CKD-related pathways to predict DN in Taiwan. This model can be used in clinical risk management practice as a screening tool to identify persons who are genetically predisposed to DN for early intervention and prevention.

Novel single nucleotide polymorphisms in gestational diabetes mellitus

The association between gestational diabetes mellitus (GDM) and single nucleotide polymorphisms (SNPs) has attracted global research attention. Exploring SNPs can help us further understand the pathogenesis of GDM, predict the risk of GDM, and guide the management of GDM patients. In this review, we summarized the studies on the association between SNPs and GDM, focusing on novel SNPs published in the last 10 years. The SNPs identified to be associated with GDM included HMG20A (rs7178572), CDKAL1 (rs7756992, rs7754840, and rs7747752), ADIPOQ (rs266729 and rs17300539), MTHFR (rs1801133), IL10 (rs3021094), CDKN2B (rs1063192), and TRPM5 (rs35197079). However, the role of SNPs in the prediction, diagnosis, treatment, and prognosis of GDM, as a polygenic disease, needs to be further explored in multiple ethnic populations.

Redox Genetic Risk Score and the Incidence of End-Stage Kidney Disease in People with Type 1 Diabetes

End-stage kidney disease (ESKD) is a multifactorial condition influenced by genetic background, but the extent to which a genetic risk score (GRS) improves ESKD prediction is unknown. We built a redox GRS on the base of previous association studies (six polymorphisms from six redox genes) and tested its relationship with ESKD in three cohorts of people with type 1 diabetes. Among 1012 participants, ESKD (hemodialysis requirement, kidney transplantation, eGFR < 15 mL/min/1.73 m²) occurred in 105 (10.4%) during a 14-year follow-up. High redox GRS was associated with increased ESKD risk (adjusted HR for the upper versus the lowest GRS tertile: 2.60 (95% CI, 1.51-4.48), p = 0.001). Each additional risk-allele was associated with a 20% increased risk of ESKD (95% CI, 8-33, p < 0.0001). High GRS yielded a relevant population attributable fraction (30%), but only a marginal enhancement in c-statistics index (0.928 [0.903-0.954]) over clinical factors 0.921 (0.892-0.950), p = 0.04). This is the first report of an independent association between redox GRS and increased risk of ESKD in type 1 diabetes. Our results do not support the use of this GRS in clinical practice but provide new insights into the involvement of oxidative stress genetic factors in ESKD risk in type 1 diabetes.

Relative leucocyte telomere length is associated with incident end-stage kidney disease and rapid decline of kidney function in type 2 diabetes: analysis from the Hong Kong Diabetes Register

AIMS/HYPOTHESIS

Few large-scale prospective studies have investigated associations between relative leucocyte telomere length (rLTL) and kidney dysfunction in individuals with type 2 diabetes. We examined relationships between rLTL and incident end-stage kidney disease (ESKD) and the slope of eGFR decline in Chinese individuals with type 2 diabetes.

METHODS

We studied 4085 Chinese individuals with type 2 diabetes observed between 1995 and 2007 in the Hong Kong Diabetes Register with stored baseline DNA and available follow-up data. rLTL was measured using quantitative PCR. ESKD was diagnosed based on the ICD-9 code and eGFR.

RESULTS

In this cohort (mean ± SD age 54.3 ± 12.6 years) followed up for 14.1 ± 5.3 years, 564 individuals developed incident ESKD and had shorter rLTL at baseline (4.2 ± 1.2 vs 4.7 ± 1.2, p < 0.001) than the non-progressors (n = 3521). On Cox regression analysis, each ∆∆Ct decrease in rLTL was associated with an increased risk of incident ESKD (HR 1.21 [95% CI 1.13, 1.30], p < 0.001); the association remained significant after adjusting for baseline age, sex, HbA1c, lipids, renal function and other risk factors (HR 1.11 [95% CI 1.03, 1.19], p = 0.007). Shorter rLTL at baseline was associated with rapid decline in eGFR (>4% per year) during follow-up (unadjusted OR 1.22 [95% CI 1.15, 1.30], p < 0.001; adjusted OR 1.09 [95% CI 1.01, 1.17], p = 0.024).

CONCLUSIONS/INTERPRETATION

rLTL is independently associated with incident ESKD and rapid eGFR loss in individuals with type 2 diabetes. Telomere length may be a useful biomarker for the progression of kidney function and ESKD in type 2 diabetes.

Gene expression profiles of diabetic kidney disease and neuropathy in eNOS knockout mice: Predictors of pathology and RAS blockade effects

Diabetic kidney disease (DKD) and diabetic peripheral neuropathy (DPN) are two common diabetic complications. However, their pathogenesis remains elusive and current therapies are only modestly effective. We evaluated genome-wide expression to identify pathways involved in DKD and DPN progression in db/db eNOS-/- mice receiving renin-angiotensin-aldosterone system (RAS)-blocking drugs to mimic the current standard of care for DKD patients. Diabetes and eNOS deletion worsened DKD, which improved with RAS treatment. Diabetes also induced DPN, which was not affected by eNOS deletion or RAS blockade. Given the multiple factors affecting DKD and the graded differences in disease severity across mouse groups, an automatic data analysis method, SOM, or self-organizing map was used to elucidate glomerular transcriptional changes associated with DKD, whereas pairwise bioinformatic analysis was used for DPN. These analyses revealed that enhanced gene expression in several pro-inflammatory networks and reduced expression of development genes correlated with worsening DKD. Although RAS treatment ameliorated the nephropathy phenotype, it did not alter the more abnormal gene expression changes in kidney. Moreover, RAS exacerbated expression of genes related to inflammation and oxidant generation in peripheral nerves. The graded increase in inflammatory gene expression and decrease in development gene expression with DKD progression underline the potentially important role of these pathways in DKD pathogenesis. Since RAS blockers worsened this gene expression pattern in both DKD and DPN, it may partly explain the inadequate therapeutic efficacy of such blockers.

Genetic risk score for risk prediction of diabetic nephropathy in Han Chinese type 2 diabetes patients

We evaluated whether genetic information could offer improvement on risk prediction of diabetic nephropathy (DN) while adding susceptibility variants into a risk prediction model with conventional risk factors in Han Chinese type 2 diabetes patients. A total of 995 (including 246 DN cases) and 519 (including 179 DN cases) type 2 diabetes patients were included in derivation and validation sets, respectively. A genetic risk score (GRS) was constructed with DN susceptibility variants based on findings of our previous genome-wide association study. In derivation set, areas under the receiver operating characteristics (AUROC) curve (95% CI) for model with clinical risk factors only, model with GRS only, and model with clinical risk factors and GRS were 0.75 (0.72-0.78), 0.64 (0.60-0.68), and 0.78 (0.75-0.81), respectively. In external validation sample, AUROC for model combining conventional risk factors and GRS was 0.70 (0.65-0.74). Additionally, the net reclassification improvement was 9.98% (P = 0.001) when the GRS was added to the prediction model of a set of clinical risk factors. This prediction model enabled us to confirm the importance of GRS combined with clinical factors in predicting the risk of DN and enhanced identification of high-risk individuals for appropriate management of DN for intervention.

Genetic characterization of early renal changes in a novel mouse model of diabetic kidney disease

Genetic factors influence susceptibility to diabetic kidney disease. Here we mapped genes mediating renal hypertrophic changes in response to diabetes. A survey of 15 mouse strains identified variation in diabetic kidney hypertrophy. Strains with greater (FVB/N(FVB)) and lesser (C57BL/6 (B6)) responses were crossed and diabetic F2 progeny were characterized. Kidney weights of diabetic F2 mice were broadly distributed. Quantitative trait locus analyses revealed diabetic mice with kidney weights in the upper quartile shared alleles on chromosomes (chr) 6 and 12; these loci were designated as Diabetic kidney hypertrophy (Dkh)-1 and -2. To confirm these loci, reciprocal congenic mice were generated with defined FVB chromosome segments on the B6 strain background (B6.Dkh1/2f) or vice versa (FVB.Dkh1/2b). Diabetic mice of the B6.Dkh1/2f congenic strain developed diabetic kidney hypertrophy, while the reciprocal FVB.Dkh1/2b congenic strain was protected. The chr6 locus contained the candidate gene; Ark1b3, coding aldose reductase; the FVB allele has a missense mutation in this gene. Microarray analysis identified differentially expressed genes between diabetic B6 and FVB mice. Thus, since the two loci identified by quantitative trait locus mapping are syntenic with regions identified for human diabetic kidney disease, the congenic strains we describe provide a valuable new resource to study diabetic kidney disease and test agents that may prevent it.

Interaction Between Susceptibility Loci in MAVS and TRAF3 Genes, and High-risk HPV Infection on the Risk of Cervical Precancerous Lesions in Chinese Population

Persistent high-risk HPV infection is considered as a major cause of cervical cancer. Nevertheless, only some infected individuals actually develop cervical cancer. The RIG-I pathway in innate immunity plays an important role in antivirus response. Here, we hypothesized that altered function of mitochondrial antiviral signaling protein (MAVS) and mitochondrial TNF receptor-associated factor 3(TRAF3), key molecules downstream of the viral sensors RIG-I, may impair their ability of clearing HPV and thereby influence the risk for cervical precancerous lesions. To investigate the effects of MAVS and TRAF3 polymorphisms on susceptibility to cervical precancerous lesions, 8 SNPs were analyzed in 164 cervical precancerous lesion cases and 428 controls. Gene-environment interactions were also calculated. We found that CA genotype of rs6052130 in MAVS gene were at 1.48 times higher risk of developing cervical precancerous lesion than individuals with CC genotype (CA vs. CC: OR_adjusted = 1.48, 95% CI, 1.02-2.16). In addition, a significant synergetic interaction between high-risk HPV infection and rs6052130 was found on an additive scale. A significantly decreased risk of cervical precancerous lesions for the TC genotype of rs12435483 in the TRAF3 gene (OR_adjusted = 0.67, 95% CI, 0.45-0.98) was also found. Moreover, MDR analysis identified a significant three-locus interaction model, involving high-risk HPV infection, TRAF3 rs12435483 and number of full-term pregnancies. Our results indicate that the MAVS rs6052130 and TRAF3 rs12435483 confer genetic susceptibility to cervical precancerous lesions. Moreover, MAVS rs6052130-mutant individuals have an increased vulnerability to high-risk HPV-induced cervical precancerous lesions.

Progression of diabetic kidney disease and trajectory of kidney function decline in Chinese patients with Type 2 diabetes

Diabetes is a major cause of end stage renal disease (ESRD), yet the natural history of diabetic kidney disease is not well understood. We aimed to identify patterns of estimated GFR (eGFR) trajectory and to determine the clinical and genetic factors and their associations of these different patterns with all-cause mortality in patients with type 2 diabetes. Among 6330 patients with baseline eGFR >60 ml/min per 1.73 m² in the Hong Kong Diabetes Register, a total of 456 patients (7.2%) developed Stage 5 chronic kidney disease or ESRD over a median follow-up of 13 years (incidence rate 5.6 per 1000 person-years). Joint latent class modeling was used to identify different patterns of eGFR trajectory. Four distinct and non-linear trajectories of eGFR were identified: slow decline (84.3% of patients), curvilinear decline (6.5%), progressive decline (6.1%) and accelerated decline (3.1%). Microalbuminuria and retinopathy were associated with accelerated eGFR decline, which was itself associated with all-cause mortality (odds ratio [OR] 6.9; 95% confidence interval [CI]: 5.6-8.4 for comparison with slow eGFR decline). Of 68 candidate genetic loci evaluated, the inclusion of five loci (rs11803049, rs911119, rs1933182, rs11123170, and rs889472) improved the prediction of eGFR trajectories (net reclassification improvement 0.232; 95% CI: 0.057--0.406). Our study highlights substantial heterogeneity in the patterns of eGFR decline among patients with diabetic kidney disease, and identifies associated clinical and genetic factors that may help to identify those who are more likely to experience an accelerated decline in kidney function.

The relationship between MnSOD Val16Ala gene polymorphism and the level of serum total antioxidant capacity with the risk of chronic kidney disease in type 2 diabetic patients: a nested case-control study in the Tehran lipid glucose study

Background

Several studies have shown significant associations between manganese superoxide dismutase (MnSOD) Val16Ala polymorphism and diabetic complications, but this association has not been explored in relation with chronic kidney disease (CKD) in Type 2 diabetes mellitus (T2DM) patients. Total antioxidant capacity (TAC) level changes in diabetic condition and may play important role in onset or progression of the disease and its complications. The present study investigated the association of MnSOD Val16Ala polymorphism and serum TAC with the risk of CKD in T2DM patients.

Methods

This nested case-control study included 280 type 2 diabetic patients with CKD and 280 age, sex and diabetes duration-matched control subjects selected from the participants of the Tehran Lipid and Glucose Study. MnSOD val16Ala (rs4880) SNP was genotyped by the Tetra-Primer ARMS-polymerase chain reaction analysis. Serum TAC was measured using ferric-reducing antioxidant power assay. Statistical analysis was performed using STATA statistical package v.12.0 or SPSS (Version 22.0).

Results

The Ala allele of the MnSOD Val16Ala polymorphism was associated with a lower risk of CKD (odds ratio (OR), 0.55; 95% confidence interval (CI), 0.36–0.84; P = 0.006). Median serum TAC in CKD group was 920 μmol/L and was significantly lower (p < 0.001) compared to the control group (1045 μmol/L). Using an adjusted conditional logistic regression, we didn’t observe any significant interaction between MnSOD Val16Ala SNP with quartiles of serum TAC in relation to CKD.

Conclusion

A significant association was found between the MnSOD Val16Ala polymorphism and CKD, but this association is not affected by serum TAC level in T2DM patients.

Meta-analyses of the association of G6PC2 allele variants with elevated fasting glucose and type 2 diabetes

Objective

To collectively evaluate the association of glucose-6-phosphatase catalytic unit 2 (G6PC2) allele variants with elevated fasting glucose (FG) and type 2 diabetes (T2D).

Design

Meta-analysis

Data sources

PubMed, Web of Knowledge and Embase databases.

Study selection

Full text articles of studies that identified an association of G6PC2 with T2D and elevated FG.

Patient involvement

There was no T2D patient involvement in the analyses on the association of FG with G6PC2, there were T2D patients and non-diabetes patient involvement in the analyses on the association of T2D with G6PC2.

Statistical analysis

Random-effects meta-analyses were used to calculate the pool effect sizes. I² metric and H² tests were used to calculate the heterogeneity. Begg's funnel plot and Egger’s linear regression test were done to assess publication bias.

Results

Of the 423 studies identified, 21 were eligible and included. Data on three loci (rs560887, rs16856187 and rs573225) were available. The G allele at rs560887 in three ethnicities, the C allele at rs16856187 and the A allele at rs573225 all had a positive association with elevated FG. Per increment of G allele at rs560887 and A allele at rs573225 resulted in a FG 0.070 mmol/l and 0.075 mmol/l higher (ß (95% CI) = 0.070 (0.060, 0.079), p = 4.635e-50 and 0.075 (0.065, 0.085), p = 5.856e-48, respectively). With regard to the relationship of rs16856187 and FG, an increase of 0.152 (95% CI: 0.034–0.270; p = 0.011) and 0.317 (95% CI: 0.193–0.442, p = 6.046e-07) was found in the standardized mean difference (SMD) of FG for the AC and CC genotypes, respectively, when compared with the AA reference genotype. However, the G-allele of rs560887 in Caucasians under the additive model and the C-allele of rs16856187 under the allele and dominant models were associated with a decreased risk of T2D (OR (95% CI) = 0.964 (0.947, 0.981), p = 0.570e-4; OR (95% CI) = 0.892 (0.832, 0.956), p = 0.001; and OR (95% CI) = 0.923(0.892, 0.955), p = 5.301e-6, respectively).

Conclusions

Our meta-analyses demonstrate that all three allele variants of G6PC2 (rs560887, rs16856187 and rs573225) are associated with elevated FG, with two variants (rs560887 in the Caucasians subgroup and rs16856187 under the allele and dominant model) being associated with T2D as well. Further studies utilizing larger sample sizes and different ethnic populations are needed to extend and confirm these findings.

Renal function in patients with diabetic foot infection; does antibiotherapy affect it?

Introduction: Antibiotic treatment (antibiotherapy) of diabetic foot ulcers has been proven to have toxic effect on renal function.

Objectives: This study aimed to evaluate renal function in patients with diabetic foot infection.

Patients and Methods: This cross-sectional retrospective study was performed on 142 patients with diabetic foot ulcers hospitalized in Shahid Yahyanejad hospital of Babol during 2013. After referring to profile of the patients, they were assigned to participate in two groups: group A consisted of patients receiving antibiotics with a low risk renal toxicity and patients who received antibiotics with a higher risk of renal toxicity were placed in group B. Glomerular filtration rate (GFR) was measured and calculated based on serum concentration of creatinine and Cockcroft-Gault equation. Data was analyzed using SPSS version 20.0 with chi-square, t test and paired t tests.

Results: Group A consisted of 74 patients (52.1%) and 68 patients (47.9%) participated in group B. GFRs before and after antibiotherapy were 64.73±33.87 cc/min and 59.10±30.51 cc/min, respectively (P=0.004). In group B, GFR decreased significantly after antibiotherapy (P=0.002).

Conclusion: According to the present study, renal function decreased after antibiotherapy and in patients who received antibiotics with higher nephrotoxicity rate, the rate of this decline was higher.

Optimising the person-centred management of type 2 diabetes

Type 2 diabetes is increasing in prevalence at a worrying rate and has been exacerbated by the worldwide obesity epidemic. The number of people in the UK diagnosed with type 2 diabetes has soared by 60% in the past 10 years. Type 2 diabetes is a very serious condition, with significant associated risks, and is the leading cause of avoidable macro- and microvascular complications. Health professionals have a key role in enabling and optimising person-centred approaches, educating and augmenting the essential skills every person, whatever his or her individual circumstances, requires for the successful self-management of this lifelong condition. This article reviews approaches to care for the management of hyperglycaemia in type 2 diabetes, which includes optimising person-centred targets, promoting individualised care, minimising the risk of complications and promoting education from diagnosis onwards.

Concerted efforts to combat diabetic complications

Kidney disease in diabetes is an important research topic in both clinical and basic science. Genetic analysis provides key translational data. In this regard, Jiang et al. emphasize some potential concerns over and problems with former genetics analysis methods, especially in common disease conditions such as kidney disease in diabetic patients.