Effect of intensive therapy on the development and progression of diabetic nephropathy in the Diabetes Control and Complications Trial. The Diabetes Control and Complications (DCCT) Research Group

Artificial intelligence based predictive tools for identifying type 2 diabetes patients at high risk of treatment Non-adherence: A systematic review

AIMS

Several Artificial Intelligence (AI) based predictive tools have been developed to predict non-adherence among patients with type 2 diabetes (T2D). Hence, this study aimed to describe and evaluate the methodological quality of AI based predictive tools for identifying T2D patients at high risk of treatment non-adherence.

METHODS

A systematic search was conducted across multiple databases including, EMBASE, Cochrane Library, MedLine, and Google Scholar search. The Prediction model Risk Of Bias ASsessment Tool (PROBAST) was used to assess the quality of studies. The performances of tools were assessed by Area Under the Curve (AUC), precision, recall, C-index, accuracy, sensitivity, specificity or F1 score.

RESULTS

Most studies measured predictive ability using AUC (75 %), and some only reported precision (25 %), recall (12.5 %), C-index (12.5 %), accuracy (37.5), sensitivity (12.5 %), specificity (12.5 %) or F1 score (25 %). All tools had moderate to high predictive ability (AUC > 0.70). However, only one study conducted external validation. Demographic characteristics, HbA1c, glucose monitoring data, and treatment details were typical factors used in developing tools.

CONCLUSIONS

The existing AI based tools holds significant promise for improving diabetes care. However, future studies should focus on refining the existing tools, validating in other settings, and evaluating the cost-effectiveness of AI-supported interventions.

Renal Status in Newly Diagnosed Patients with Diabetes Mellitus: A Descriptive Study in Primary Care and Opportunities for Improving Management

Background/Objectives: The current study aims to estimate the frequency of abnormal renal status (ARS, defined as chronic kidney disease (CKD) diagnosis in electronic medical records or current albuminuria) in people with newly diagnosed diabetes mellitus (DM), to determine the associated risk factors, and to evaluate the level of compliance with good clinical practice recommendations. Methods: Cross-sectional study with 1030 adults diagnosed with DM in the last 4 years. Anthropometric, clinical, analytical, and lifestyle variables were collected. Multivariate analyses were performed to determine the factors associated with ARS. Results: Hypercholesterolaemia, metabolic syndrome, hypertension, obesity, hypertriglyceridaemia, and cardiovascular disease (CVD) were the most prevalent comorbidities. ARS was present in 11.5% of patients. The variables associated with ARS were male sex (OR: 1.78; 95% CI, 1.16-2.75), age ≥70 years (OR: 2.96; 95% CI: 1.92-4.56), hypertension (OR: 1.59; 95% CI: 1.03-2.44), CVD (OR: 1.73; 95% CI: 1.03-2.90), and hemoglobin A1c (HbA1c) ≥8% (OR: 2.26; 95% CI, 1.19-4.27). Among patients with hypertension and albuminuria, 80% received angiotensin-converting enzyme inhibitors (ACE inhibitor) or an angiotensin receptor blocker (ARB), compared to 60% of those with albuminuria without hypertension. The 42.4% patients with ARS were treated with sodium-glucose cotransporter type 2 inhibitors (SGLT2i) and 72% with statins, but only 31.5% achieved the target low density lipoproteins cholesterol (LDLc) < 70 mg/dL. Conclusions: ARS in newly diagnosed patients with DM is less common than described in the literature, but risk factors for its development are highly prevalent. Adherence to good clinical practice recommendations was poor, especially in LDL cholesterol targets and the use of SGLT2i.

Lessons learned from the FinnDiane Study: Epidemiology and metabolic risk factors for diabetic kidney disease in type 1 diabetes

AIMS

Across its operational span of more than 25 years, the observational, nationwide, multicentre Finnish Diabetic Nephropathy (FinnDiane) Study has aimed to unravel mechanisms underlying diabetic kidney disease, with a special focus on its metabolic risk factors. We sought to compile key findings relating to this topic and to offer a current perspective on the natural course of diabetic kidney disease among individuals with type 1 diabetes.

METHODS

In this narrative review, articles relevant to the subject published by the FinnDiane Study were identified and summarized together with work published by others, when relevant.

RESULTS

The FinnDiane Study has underscored the significance of dysglycaemia and insulin resistance, increased visceral fat mass, hypertension and dyslipidaemia-particularly high triglycerides and remnant cholesterol-as risk factors for diabetic kidney disease. Factors like abdominal obesity seem to influence the early stages of the disease, while the presence of the metabolic syndrome becomes implicated at later stages. Epidemiological reports have revealed that after an initial decline, the cumulative incidence of albuminuria plateaued post-1980s, with the progression rate to kidney failure remaining high. Fortunately, 23% of the FinnDiane cohort regressed to less advanced stages of albuminuria, improving their overall prognosis.

CONCLUSION

A substantial burden of albuminuria associated with type 1 diabetes persists, and therefore, novel kidney-protecting therapies are highly awaited. In addition, given that metabolic factors influence the progression of diabetic kidney disease both in its early and advanced stages, emphasis should be placed on ensuring that their treatment targets are met.

Identification of metabolic reprogramming-related genes as potential diagnostic biomarkers for diabetic nephropathy based on bioinformatics

BACKGROUND

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus, marked by progressive renal damage. Recent evidence indicates that metabolic reprogramming is crucial to DN pathogenesis, yet its underlying mechanisms are not well understood. This study aimed to examine how metabolic reprogramming-related genes (MRRGs) are differentially expressed and to explore their potential mechanisms in the development of DN.

METHODS

We analyzed the datasets GSE30528 and GSE96804 from the Gene Expression Omnibus (GEO), comprising 50 DN samples and 33 controls. MRRGs were sourced from GeneCards and PubMed. Data preprocessing included batch effect correction using the R package sva, followed by normalization and differential expression analysis with limma (|logFC|> 0.5, adj.p < 0.05). Functional enrichment analyses (GO, KEGG, GSEA) were performed using clusterProfiler. Protein-protein interaction (PPI) networks were constructed via STRING, identifying hub genes through CytoHubba. Regulatory networks (mRNA-TF, mRNA-miRNA) were derived from ChIPBase and StarBase. Validation of hub genes and ROC analysis assessed diagnostic performance. ssGSEA quantified immune cell infiltration.

RESULTS

Our analysis identified 708 differentially expressed genes (DEGs), including 119 metabolic reprogramming-related DEGs (MRRDEGs). Enrichment analyses revealed significant roles for MRRDEGs in processes such as wound healing and pathways like MAPK signaling. The PPI network identified nine hub genes: FN1, CD44, KDR, EGF, HSPG2, HGF, FGF9, IGF1, and ALB, which exhibited high diagnostic accuracy (AUC 0.7 to 0.9). Notably, FN1 and CD44 showed significant association with renal fibrosis and could serve as potential biomarkers for early diagnosis and therapeutic targets in DN. Immune infiltration analysis showed notable differences in immune cell composition between DN and control samples.

CONCLUSION

This study identifies hub genes such as FN1 and CD44, with potential diagnostic value in DN. It also reveals immune cell infiltration differences between DN patients and controls, offering insights into disease progression and potential therapeutic targets.

Reference Interval for Glycated Albumin, 1,5-AG/GA, and GA/HbA1c Ratios and Cut-Off Values for Type 1, Type 2, and Gestational Diabetes: A Cross-Sectional Study

Background/Objectives: Glycated albumin (GA) serves as a biomarker for short-term glycemic control (2-3 weeks), playing a role in diabetes management. Our goal was to establish reference intervals (RIs) for serum GA, and the ratios of 1,5-anhydroglucitol to GA (AGI) and GA to HbA1c in a Euro-Brazilian pediatric population (10 y, n = 299), adults (43.5 y; n = 290), and pregnant women (26 y, n = 406; 26.5 ± 3.1 gestation weeks). Methods: Receiver operating characteristic curve analysis was employed to determine RIs for type 1 diabetes (T1D) in children (n = 148) and adults (n = 81), type 2 diabetes (T2D, n = 283), and gestational diabetes mellitus (GDM, n = 177). Results: Both non-pregnant and pregnant women exhibited GA RIs of 10.0-13.3% and 10.6-14.7%, respectively. The AGI ratio varied from 1.2-4.3 in children, 0.9-3.6 in adults, and 0.8-3.1 in pregnant women. Meanwhile, the GA/HbA1c ratio ranged from 1.8-2.6 in children and adults to 2.3-3.6 in pregnant women. GA and AGI ratios accurately differentiated between T1D and T2D, demonstrating high sensitivity (>84%) and specificity (>97%), with AGI showing superior performance (AUC > 0.99). The GA/HbA1c ratio exhibited moderate discriminatory power (AUC > 0.733) but was less effective in distinguishing adult-onset T1D and T2D, suggesting its limited utility in certain groups. Conclusions: The proposed RIs are consistent with those of other Caucasian populations, affirming their relevance for Euro-Brazilian patients. The GA and AGI ratios emerge as valuable diagnostic tools for T1D and T2D, though their reduced sensitivity in diagnosing GDM warrants further investigation. Clinicians might leverage GA and AGI ratios for more tailored diabetes management, especially when HbA1c results are not optimal.

Classification of longitudinal estimated glomerular filtration rate trajectories in Canadian adults with type 1 diabetes

AIMS

Type 1 diabetes (T1D) increases the risk of chronic kidney disease (CKD) development. The aims of this study were to classify trajectories of estimated glomerular filtration rate (eGFR) in a cohort of Canadian adults with T1D, and to describe the risk factors associated with declining eGFR trajectories.

METHODS

In this retrospective cohort of adults with T1D, data was collected between 1996 and 2020. CKD was defined as eGFR <60 mL/min/1.73 m2. Latent class mixed models were used to categorize eGFR trajectories. Multinomial logistic regression was used to identify factors associated with declining eGFR trajectories.

RESULTS

In this study, 304 adults were analyzed, with baseline measurements at a median duration of T1D of 15.3 (5.4-24.2) years. Eight percent of the cohort developed CKD over a median duration of 24.3 (13.7-34.8) years. Four classes of longitudinal eGFR trajectories were identified, broadly categorized as steeply declining (SD1, SD2) and gradual declining (GD1, GD2). Female sex, poor glycemic control, elevated body mass index, and albuminuria were associated with a steeply declining trajectory.

CONCLUSION

In this cohort, four distinctive eGFR trajectories were identified, including a subtype with steeply declining eGFR. Given the complex nature of CKD progression, further prospective study of this model for identification of individuals at risk for CKD based on their trajectory of kidney function may support clinicians in their decision-making.

Poor Glycemic Control Is Associated With More Rapid Kidney Function Decline After the Onset of Diabetic Kidney Disease

BACKGROUND

The role of glycemic control and its variability on the rate of kidney function decline after the onset of diabetic kidney disease (DKD) remains unclear.

METHODS

The association between baseline glycated hemoglobin (HbA1c) and rates of estimated glomerular filtration rate (eGFR) loss during follow-up was examined by mixed-effects linear regression in 530 individuals with type 1 diabetes and early-to-moderate DKD from the Preventing Early Renal Loss (PERL) trial and 2378 individuals with type 2 diabetes and established DKD from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. The benefit of intensive vs standard glycemic control in slowing eGFR decline was examined in ACCORD. The associations between continuous glucose monitoring-derived short-term glycemic variability indices and rate of eGFR decline were also evaluated in PERL.

RESULTS

A higher baseline HbA1c was associated with a more negative eGFR slope in both PERL and ACCORD (-0.87 and -0.27 mL/min/1.73 m2/year per Hba1c unit increment, P < .0001 and P = .0002, respectively). In both studies, the strength of this association progressively increased with increasing levels of albuminuria (P for interaction <.05). Consistent with this, the benefit of intensive glycemic control on eGFR decline was greater in ACCORD participants with severe rather than moderate albuminuria (+1.13 vs + 0.26 mL/min/1.73 m2/year, P = .01). No independent associations were found in PERL between short-term glycemic variability indices and rate of eGFR decline.

CONCLUSION

In both type 1 and type 2 diabetes, poor glycemic control is associated with a more rapid rate of glomerular filtration rate decline after DKD onset, especially in persons with severe albuminuria.

High glucose-induced downregulation of PTEN-Long is sufficient for proximal tubular cell injury in diabetic kidney disease

During the progression of diabetic kidney disease, proximal tubular epithelial cells respond to high glucose to induce hypertrophy and matrix expansion leading to renal fibrosis. Recently, a non-canonical PTEN has been shown to be translated from an upstream initiation codon CUG (leucine) to produce a longer protein called PTEN-Long (PTEN-L). Interestingly, the extended sequence present in PTEN-L contains cell secretion/penetration signal. Role of this non-canonical PTEN-L in diabetic renal tubular injury is not known. We show that high glucose decreases expression of PTEN-L. As a mechanism of its function, we find that reduced PTEN-L activates Akt-2, which phosphorylates and inactivate tuberin and PRAS40, resulting in activation of mTORC1 in tubular cells. Antibacterial agent acriflavine and antiviral agent ATA regulate translation from CUG codon. Acriflavine and ATA, respectively, decreased and increased expression of PTEN-L to altering Akt-2 and mTORC1 activation in the absence of change in expression of canonical PTEN. Consequently, acriflavine and ATA modulated high glucose-induced tubular cell hypertrophy and lamininγ1 expression. Importantly, expression of PTEN-L inhibited high glucose-stimulated Akt/mTORC1 activity to abrogate these processes. Since PTEN-L contains secretion/penetration signals, addition of conditioned medium containing PTEN-L blocked Akt-2/mTORC1 activity. Notably, in renal cortex of diabetic mice, we found reduced PTEN-L concomitant with Akt-2/mTORC1 activation, leading to renal hypertrophy and lamininγ1 expression. These results present first evidence for involvement of PTEN-L in diabetic kidney disease.

Renal functional outcomes after nephrectomy in patients with localized renal cell carcinoma and diabetes mellitus: a systematic review and meta-analysis

INTRODUCTION AND OBJECTIVE

Diabetes mellitus (DM), one of the most common comorbidities in patients with renal cell carcinoma (RCC), was proven to be an important prognostic factor of overall survival for these patients. Regarding the influence on renal function after nephrectomy, evidence is still scant. This systematic review and meta-analysis was conducted to provide a more reliable analysis of the association between DM and long-term renal functional outcomes after nephrectomy.

METHODS

The PubMed, Web of Science, Embase and Cochrane Library (CENTRAL) databases were searched for eligible studies from inception to January 2023. Hazard ratios (HRs) with 95% confidence intervals (CIs) were extracted to evaluate the association between DM and renal functional outcomes using a random effects model. Stata 17.0 software was used for statistical analysis.

RESULTS

The meta-analysis included thirteen studies consisting of 8562 RCC patients who underwent nephrectomy. Preoperative comorbidity of DM was significantly associated with poor renal functional outcomes (HR = 1.91, 95% CI 1.48-2.48, p < 0.0001), regardless of ethnicity, follow-up time, body mass index (BMI) and age. However, in the radical nephrectomy subgroup, DM was not significantly associated with renal function decline (HR = 1.91, 95% CI 0.93-3.90, p = 0.0781).

CONCLUSIONS

The aggregate evidence indicated that preexisting DM may be associated with poor renal functional outcomes in patients with RCC after nephrectomy, especially in patients receiving partial nephrectomy. Urologists should focus more on the glycemic management of these patients after nephrectomy. More high-quality studies are needed to explore the influence of DM on renal function outcomes in postoperative patients.

Elevated apolipoprotein C3 augments diabetic kidney disease and associated atherosclerosis in type 2 diabetes

Diabetes increases the risk of both cardiovascular disease and kidney disease. Notably, most of the excess cardiovascular risk in people with diabetes is in those with kidney disease. Apolipoprotein C3 (APOC3) is a key regulator of plasma triglycerides, and it has recently been suggested to play a role in both type 1 diabetes-accelerated atherosclerosis and kidney disease progression. To investigate if APOC3 plays a role in kidney disease in people with type 2 diabetes, we analyzed plasma levels of APOC3 from the Veterans Affairs Diabetes Trial. Elevated baseline APOC3 levels predicted a greater loss of renal function. To mechanistically test if APOC3 plays a role in diabetic kidney disease and associated atherosclerosis, we treated black and tan, brachyury, WT and leptin-deficient (OB; diabetic) mice, a model of type 2 diabetes, with an antisense oligonucleotide (ASO) to APOC3 or a control ASO, all in the setting of human-like dyslipidemia. Silencing APOC3 prevented diabetes-augmented albuminuria, renal glomerular hypertrophy, monocyte recruitment, and macrophage accumulation, partly driven by reduced ICAM1 expression. Furthermore, reduced levels of APOC3 suppressed atherosclerosis associated with diabetes. This suggests that targeting APOC3 might benefit both diabetes-accelerated atherosclerosis and kidney disease.

Twenty-Four week Taichi training improves pulmonary diffusion capacity and glycemic control in patients with Type 2 diabetes mellitus

This study evaluated the effect of 24-week Taichi training and Taichi plus resistance band training on pulmonary diffusion capacity and glycemic control in patients with Type 2 diabetes mellitus (T2DM). Forty-eight patients with T2DM were randomly divided into three groups: Group A-Taichi training: practiced Taichi 60 min/day, 6 days/week for 24 weeks; Group B-Taichi plus resistance band training: practiced 60-min Taichi 4 days/week plus 60-min resistance band training 2 days/week for 24 weeks; and Group C-controls: maintaining their daily lifestyles. Stepwise multiple regression analysis was applied to predict diffusion capacity of the lungs for carbon monoxide (DLCO) by fasting blood glucose, insulin, glycosylated hemoglobin (HbA1c), tumour necrosis factor alpha (TNF-α), von Willebrand Factor (vWF), interleukin-6 (IL-6), intercellular adhesion molecule 1 (ICAM-1), endothelial nitric oxide synthase (eNOS), nitric oxide (NO), endothelin-1 (ET-1), vascular endothelial growth factor, and prostaglandin I-2. Taichi with or without resistance band training significantly improved DLCO, increased insulin sensitivity, eNOS and NO, and reduced fasting blood glucose, insulin, HbA1c, TNF-α, vWF, IL-6, ICAM-1, and ET-1. There was no change in any of these variables in the control group. DLCO was significantly predicted (R2 = 0.82) by insulin sensitivity (standard-β = 0.415, P<0.001), eNOS (standard-β = 0.128, P = 0.017), TNF-α (standard-β = -0.259, P = 0.001), vWF (standard-β = -0.201, P = 0.007), and IL-6 (standard-β = -0.175, P = 0.032) in patients with T2DM. The impact of insulin sensitivity was the most important predictor for the variation of DLCO based on the multiple regression modeling. This study demonstrates that 24-week Taichi training and Taichi plus resistance band training effectively improve pulmonary diffusion capacity and blood glycemic control in patients with T2DM. Variation of DLCO is explained by improved insulin sensitivity and endothelial function, and reduced inflammatory markers, including TNF-α, vWF, and IL-6.

U-shaped relationship between fasting blood glucose and urinary albumin-to-creatinine ratio in the general United States population

Objective

The current controversy surrounding the association between fasting blood glucose (FBG) and albuminuria necessitates further investigation. Hence, the primary objective of this study was to examine the relationship between FBG and urinary albumin-to-creatinine ratio (UACR).

Methods

A cohort of complete data from National Health and Nutrition Examination Survey (NHANES) participants (1999-2020) was analyzed. Linear regression analyses and a generalized additive model explored the association between FBG and UACR. Furthermore, the stability of this relationship across different populations was assessed.

Results

The study involved a total of 20,264 participants who were identified as U.S. citizens. By employing linear regression analysis, a statistically significant relationship was observed between elevated FBG levels and an increase in UACR (P<0.0001). Additionally, using a generalized additive model analysis, a U-shaped correlation between FBG and UACR was identified. Further examination using threshold effect analysis indicated a turning point for FBG at 5.44 mmol/L. A noteworthy finding in multiple populations is the consistent U-shaped association between FBG and UACR, except for individuals with serum uric acid levels ≥420 μmol/L and those who refrain from alcohol consumption.

Conclusion

The general U.S. population has a U-shaped nonlinear relationship between FBG and UACR.

Hyperglycemia - A culprit of podocyte pathology in the context of glycogen metabolism

Prolonged disruption in the balance of glucose can result in metabolic disorders. The kidneys play a significant role in regulating blood glucose levels. However, when exposed to chronic hyperglycemia, the kidneys' ability to handle glucose metabolism may be impaired, leading to an accumulation of glycogen. Earlier studies have shown that there can be a significant increase in glucose storage in the form of glycogen in the kidneys in diabetes. Podocytes play a crucial role in maintaining the integrity of filtration barrier. In diabetes, exposure to elevated glucose levels can lead to significant metabolic and structural changes in podocytes, contributing to kidney damage and the development of diabetic kidney disease. The accumulation of glycogen in podocytes is not a well-established phenomenon. However, a recent study has demonstrated the presence of glycogen granules in podocytes. This review delves into the intricate connections between hyperglycemia and glycogen metabolism within the context of the kidney, with special emphasis on podocytes. The aberrant storage of glycogen has the potential to detrimentally impact podocyte functionality and perturb their structural integrity. This review provides a comprehensive analysis of the alterations in cellular signaling pathways that may potentially lead to glycogen overproduction in podocytes.

Screening, identifying, and treating chronic kidney disease: why, who, when, how, and what?

1 in 7 American adults have chronic kidney disease (CKD); a disease that increases risk for CKD progression, cardiovascular events, and mortality. Currently, the US Preventative Services Task Force does not have a screening recommendation, though evidence suggests that screening can prevent progression and is cost-effective. Populations at risk for CKD, such as those with hypertension, diabetes, and age greater than 50 years should be targeted for screening. CKD is diagnosed and risk stratified with estimated glomerular filtration rate utilizing serum creatinine and measuring urine albumin-to-creatinine ratio. Once identified, CKD is staged according to C-G-A classification, and managed with lifestyle modification, interdisciplinary care and the recently expanding repertoire of pharmacotherapy which includes angiotensin converting enzyme inhibitors or angiotensin-II receptor blockers, sodium-glucose-cotransporter-2 inhibitors, and mineralocorticorticoid receptor antagonists. In this paper, we present the why, who, when, how, and what of CKD screening.

The vascular complications of diabetes: a review of their management, pathogenesis, and prevention

INTRODUCTION

This review highlights the pathogenesis of both microvascular and macrovascular complications of diabetes and how these mechanisms influence both the management and preventative strategies of these complications. The cumulative data shown in this review suggest hyperglycemic and blood pressure control remain central to this intricate process.

AREAS COVERED

We reviewed the literature including retrospective, prospective trials as well as meta-analysis, and post hoc analysis of randomized trials on microvascular andmacrovascular complications.

EXPERT OPINION

Further research is needed to explore the ideal intervention targets and preventative strategies needed to prevent macrovascular complications. Furthermore, as the data for trials looking at microvascular complications lengthen more long-term data will further elucidate the role that the duration of diabetes has on these complications. Additionally, trials looking to maximize hyperglycemic control with multiple agents in diabetes, such as metformin, SGL2isand GLP-1 receptor agonists are currently in process, which will have implications for rates of microvascular as well as macrovascular complications.

Incretin Therapies for Patients with Type 2 Diabetes and Chronic Kidney Disease

Since the early 2000s, an influx of novel glucose-lowering agents has changed the therapeutic landscape for treatment of diabetes and diabetes-related complications. Glucagon-like peptide-1 (GLP-1) receptor agonists represent an important therapeutic class for the management of type 2 diabetes (T2D), demonstrating benefits beyond glycemic control, including lowering of blood pressure and body weight, and importantly, decreased risk of development of new or worsening chronic kidney disease (CKD) and reduced rates of atherosclerotic cardiovascular events. Plausible non-glycemic mechanisms that benefit the heart and kidneys with GLP-1 receptor agonists include anti-inflammatory and antioxidant effects. Further supporting their use in CKD, the glycemic benefits of GLP-1 receptor agonists are preserved in moderate-to-severe CKD. Considering current evidence, major guideline-forming organizations recommend the use of GLP-1 receptor agonists in cases of T2D and CKD, especially in those with obesity and/or in those with high cardiovascular risk or established heart disease. Evidence continues to build that supports benefits to the heart and kidneys of the dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) receptor agonist tirzepatide. Ongoing outcome and mechanistic studies will continue to inform our understanding of the role of GLP-1 and dual GLP-1/GIP receptor agonists in diverse patient populations with kidney disease.

Managing comorbidities in chronic kidney disease reduces utilization and costs

BACKGROUND

Effective management of comorbid diabetes and hypertension in patients with chronic kidney disease (CKD) is important for optimal outcomes. However, little is known about this relationship from a health plan perspective. The objective of this study was to evaluate the association of effective management of comorbid diabetes and/or hypertension with healthcare resource utilization (HCRU) in patients with chronic kidney disease (CKD).

METHODS

This retrospective cohort study used the Humana Research Database to identify patients with CKD Stage ≥ 3a in 2017. Eligible patients were enrolled in a Medicare Advantage Prescription Drug plan for ≥ 12 months before and after the index date (first observed evidence of CKD). Patients with end-stage renal disease, kidney transplant, or hospice election preindex were excluded. Recommended comorbid disease management included hemoglobin A1c monitoring; adherence to glucose-lowering, cardiovascular, and angiotensin-converting enzyme inhibitors/angiotensin receptor blocker medications; and nephrologist/primary care provider (PCP) visits. HCRU was evaluated for 12 months postindex.

RESULTS

The final cohort of 241,628 patients was 55% female and 77% White, with an average age of 75 years. Approximately 90% of patients had Stage 3 CKD. Half had both diabetes and hypertension, and most of the remaining half had hypertension without diabetes. Patients meeting the criteria for good disease management, compared with patients not meeting those criteria, were less likely to experience an inpatient hospitalization, by as much as 40% depending on the criterion and the comorbidities present, or an emergency department visit, by as much as 30%. Total monthly healthcare costs were as much as 17% lower.

CONCLUSIONS

Management of comorbid diabetes and hypertension in patients with CKD was associated with lower HCRU and costs. Care coordination programs targeting patients with CKD must give careful attention to glucose and blood pressure control.

TRIAL REGISTRATION

Not applicable.

Plasma Biomarkers and Incident CKD Among Individuals Without Diabetes

Rationale & Objective

Biomarkers of kidney disease progression have been identified in individuals with diabetes and underlying chronic kidney disease (CKD). Whether or not these markers are associated with the development of CKD in a general population without diabetes or CKD is not well established.

Study Design

Prospective observational cohort.

Setting & Participants

In the Atherosclerosis Risk in Communities) study, 948 participants were studied.

Exposures

The baseline plasma biomarkers of kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein-1 (MCP-1), soluble urokinase plasminogen activator receptor (suPAR), tumor necrosis factor receptor 1 (TNFR-1), tumor necrosis factor receptor 2 (TNFR-2), and human cartilage glycoprotein-39 (YKL-40) measured in 1996-1998.

Outcome

Incident CKD after 15 years of follow-up defined as ≥40% estimated glomerular filtration rate decline to <60 mL/min/1.73 m2 or dialysis dependence through United States Renal Data System linkage.

Analytical Approach

Logistic regression and C statistics.

Results

There were 523 cases of incident CKD. Compared with a random sample of 425 controls, there were greater odds of incident CKD per 2-fold higher concentration of KIM-1 (OR, 1.49; 95% CI, 1.25-1.78), suPAR (OR, 2.57; 95% CI, 1.74-3.84), TNFR-1 (OR, 2.20; 95% CI, 1.58-3.09), TNFR-2 (OR, 2.03; 95% CI, 1.37-3.04). After adjustment for all biomarkers, KIM-1 (OR, 1.42; 95% CI, 1.19-1.71), and suPAR (OR, 1.86; 95% CI, 1.18-2.92) remained associated with incident CKD. Compared with traditional risk factors, the addition of all 6 biomarkers improved the C statistic from 0.695-0.731 (P < 0.01) and using the observed risk of 12% for incident CKD, the predicted risk gradient changed from 5%-40% (for the 1st-5th quintile) to 4%-44%.

Limitations

Biomarkers and creatinine were measured at one time point.

Conclusions

Higher levels of KIM-1, suPAR, TNFR-1, and TNFR-2 were associated with higher odds of incident CKD among individuals without diabetes.

Plain-Language Summary

For people with diabetes or kidney disease, several biomarkers have been shown to be associated with worsening kidney disease. Whether these biomarkers have prognostic significance in people without diabetes or kidney disease is less studied. Using the Atherosclerosis Risk in Communities study, we followed individuals without diabetes or kidney disease for an average of 15 years after biomarker measurement to see if these biomarkers were associated with the development of kidney disease. We found that elevated levels of KIM-1, suPAR, TNFR-1, and TNFR-2 were associated with the development of kidney disease. These biomarkers may help identify individuals who would benefit from interventions to prevent the development of kidney disease.

Risk of rapid progression to dialysis in patients with type 2 diabetes mellitus with and without diabetes-related complications at diagnosis

Many adults with diabetes mellitus are unaware worldwide. The study objectives aimed to evaluate the risk of dialysis within 5 years of diagnosis between patients with newly diagnosed diabetes with and without diabetes-related complications. A retrospective longitudinal nationwide cohort study was conducted. Patients diagnosed with diabetes between 2005 and 2013 were followed up until 2018. They were categorized based on the presence or absence of complications, the number of complications, and the diabetes complications severity index (DCSI) scores. Dialysis outcomes were determined through the Registry of Catastrophic Illness from the National Health Insurance Research Database. Among the analyzed patients, 25.38% had complications at diagnosis. Patients with complications at diagnosis had a significantly higher risk of dialysis within 5 years (adjusted hazard ratio: 9.55, 95% confidence interval CI 9.02-10.11). Increasing DCSI scores and the number of complications were associated with higher dialysis risks. Patients with one complication had a 7.26-times higher risk (95% CI 6.83-7.71), while those with ≥ 3 complications had a 36.12-times higher risk (95% CI 32.28-40.41). In conclusion, newly diagnosed diabetes patients with complications face an increased risk of dialysis within 5 years. The severity and number of complications are directly linked to the risk of dialysis within this timeframe.

Kidney Considerations in Pediatric Obesity

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is a common condition and a major cause of morbidity and mortality in adults, but children and adolescents are also at risk for early kidney injury and development of CKD. Obesity contributes both directly and indirectly to the development of CKD. The purpose of this review is to describe obesity-related kidney disease (ORKD) and diabetic kidney disease (DKD) and their impact in the pediatric population.

RECENT FINDINGS

Although obesity-related CKD in childhood and adolescence is uncommon, nascent kidney damage may magnify the lifetime risk of CKD. Glomerular hyperfiltration is an early phenotype of both ORKD and DKD and typically manifests prior to albuminuria and progressive decline in GFR. Novel treatments for obesity and type 2 diabetes exerting protective effects on the kidneys are being investigated for use in the pediatric population. It is important to understand the impact of obesity on the kidneys more fully in the pediatric population to help detect injury earlier and intervene prior to the onset of irreversible progression of disease and to guide future research in this area.

Glycemic Control and Adverse Clinical Outcomes in Patients with Chronic Kidney Disease and Type 2 Diabetes Mellitus: Results from KNOW-CKD

BACKGRUOUND

The optimal level of glycosylated hemoglobin (HbA1c) to prevent adverse clinical outcomes is unknown in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM).

METHODS

We analyzed 707 patients with CKD G1-G5 without kidney replacement therapy and T2DM from the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD), a nationwide prospective cohort study. The main predictor was time-varying HbA1c level at each visit. The primary outcome was a composite of development of major adverse cardiovascular events (MACEs) or all-cause mortality. Secondary outcomes included the individual endpoint of MACEs, all-cause mortality, and CKD progression. CKD progression was defined as a ≥50% decline in the estimated glomerular filtration rate from baseline or the onset of end-stage kidney disease.

RESULTS

During a median follow-up of 4.8 years, the primary outcome occurred in 129 (18.2%) patients. In time-varying Cox model, the adjusted hazard ratios (aHRs) for the primary outcome were 1.59 (95% confidence interval [CI], 1.01 to 2.49) and 1.99 (95% CI, 1.24 to 3.19) for HbA1c levels of 7.0%-7.9% and ≥8.0%, respectively, compared with <7.0%. Additional analysis of baseline HbA1c levels yielded a similar graded association. In secondary outcome analyses, the aHRs for the corresponding HbA1c categories were 2.17 (95% CI, 1.20 to 3.95) and 2.26 (95% CI, 1.17 to 4.37) for MACE, and 1.36 (95% CI, 0.68 to 2.72) and 2.08 (95% CI, 1.06 to 4.05) for all-cause mortality. However, the risk of CKD progression did not differ between the three groups.

CONCLUSION

This study showed that higher HbA1c levels were associated with an increased risk of MACE and mortality in patients with CKD and T2DM.

Mortality assessment for pancreas transplants in the United States over the decade 2008-2018

BACKGROUND

Pancreas transplant is the only treatment that establishes normal glucose levels for patients diagnosed with diabetes. However, since 2005, no comprehensive analysis has compared survival outcomes of: (1) Simultaneous pancreas-kidney (SPK) transplant; (2) Pancreas after kidney (PAK) transplant; and (3) Pancreas transplant alone (PTA) to waitlist survival.

AIM

To explore the outcomes of pancreas transplants in the United States during the decade 2008-2018.

METHODS

Our study utilized the United Network for Organ Sharing Standard Transplant Analysis and Research file. Pre- and post-transplant recipient and waitlist characteristics and the most recent recipient transplant and mortality status were used. We included all patients with type I diabetes listed for pancreas or kidney-pancreas transplant between May 31, 2008 and May 31, 2018. Patients were grouped into one of three transplant types: SPK, PAK, or PTA.

RESULTS

The adjusted Cox proportional hazards models comparing survival between transplanted and non-transplanted patients in each transplant type group showed that patients who underwent an SPK transplant exhibited a significantly reduced hazard of mortality [hazard ratio (HR) = 0.21, 95% confidence intervals (CI): 0.19-0.25] compared to those not transplanted. Neither PAK transplanted patients (HR = 1.68, 95%CI: 0.99-2.87) nor PTA patients (HR = 1.01, 95%CI: 0.53-1.95) experienced significantly different hazards of mortality compared to patients who did not receive a transplant.

CONCLUSION

When assessing each of the three transplant types, only SPK transplant offered a survival advantage compared to patients on the waiting list. PKA and PTA transplanted patients demonstrated no significant differences compared to patients who did not receive a transplant.

Hyaluronan Inhibition as a Therapeutic Target for Diabetic Kidney Disease: What Is Next?

Diabetic kidney disease (DKD) is the leading cause of CKD and ESKD in the United States and worldwide. Pharmacotherapy and lifestyle modifications for glycemia, dyslipidemia, and BP control have shown success in slowing the progression of DKD. Traditional treatments, such as angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and more recently the use of sodium-glucose cotransporter 2 inhibitors, nonsteroidal selective mineralocorticoid receptor antagonists, such as finerenone, and glucagon-like peptide 1 receptor agonists, have led to added benefits on various outcomes. However, significant residual risk for DKD progression remains despite the current standard-of-care approaches. Arteriolar hyalinosis (AH) is among the key findings seen on kidney biopsies of patients with DKD. It results from the excessive accumulation of hyaluronan (HA) in the arterioles. AH has not been targeted specifically by any of the therapeutic methods currently being used. We discuss in this manuscript the potential use of a selective therapy targeting AH and the increased total renal HA deposits using a HA synthesis inhibitor in DKD.

An Assessment of How Clinicians and Staff Members Use a Diabetes Artificial Intelligence Prediction Tool: Mixed Methods Study

BACKGROUND

Nearly one-third of patients with diabetes are poorly controlled (hemoglobin A1c≥9%). Identifying at-risk individuals and providing them with effective treatment is an important strategy for preventing poor control.

OBJECTIVE

This study aims to assess how clinicians and staff members would use a clinical decision support tool based on artificial intelligence (AI) and identify factors that affect adoption.

METHODS

This was a mixed methods study that combined semistructured interviews and surveys to assess the perceived usefulness and ease of use, intent to use, and factors affecting tool adoption. We recruited clinicians and staff members from practices that manage diabetes. During the interviews, participants reviewed a sample electronic health record alert and were informed that the tool uses AI to identify those at high risk for poor control. Participants discussed how they would use the tool, whether it would contribute to care, and the factors affecting its implementation. In a survey, participants reported their demographics; rank-ordered factors influencing the adoption of the tool; and reported their perception of the tool's usefulness as well as their intent to use, ease of use, and organizational support for use. Qualitative data were analyzed using a thematic content analysis approach. We used descriptive statistics to report demographics and analyze the findings of the survey.

RESULTS

In total, 22 individuals participated in the study. Two-thirds (14/22, 63%) of respondents were physicians. Overall, 36% (8/22) of respondents worked in academic health centers, whereas 27% (6/22) of respondents worked in federally qualified health centers. The interviews identified several themes: this tool has the potential to be useful because it provides information that is not currently available and can make care more efficient and effective; clinicians and staff members were concerned about how the tool affects patient-oriented outcomes and clinical workflows; adoption of the tool is dependent on its validation, transparency, actionability, and design and could be increased with changes to the interface and usability; and implementation would require buy-in and need to be tailored to the demands and resources of clinics and communities. Survey findings supported these themes, as 77% (17/22) of participants somewhat, moderately, or strongly agreed that they would use the tool, whereas these figures were 82% (18/22) for usefulness, 82% (18/22) for ease of use, and 68% (15/22) for clinic support. The 2 highest ranked factors affecting adoption were whether the tool improves health and the accuracy of the tool.

CONCLUSIONS

Most participants found the tool to be easy to use and useful, although they had concerns about alert fatigue, bias, and transparency. These data will be used to enhance the design of an AI tool.

Differential correlation between time in range and eGFR or albuminuria in type 2 diabetes

INTRODUCTION

As a CGM-derived indicator, 'time in range' (TIR) is emerging as a key indicator for accurate assessment of glycaemic control. However, there is few report focusing on the correlation of TIR with albumuria and renal fuction. The aim of this work was to investigate whether TIR, as well as nocturnal TIR and hypoglycaemic events is related to the presence and severity of albuminuria and decrease of eGFR in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 823 patients were enrolled in this study. All patients received continuous glucose monitoring, TIR indicating the percentage of time that blood glucose was in the range of 3.9-10.0 mmol/L. The Spearman analysis was applied to analyze the relationship between TIR (or nocturnal TIR) and ACR. Logistic regression was used to explore whether TIR (or nocturnal TIR) is an independent risk factor for albuminuria.

RESULTS

The prevalence of albuminuria decreased with increasing TIR quartiles. Binary logistic regression revealed that TIR as well as nocturnal TIR was obviously related to the presence of albuminuria. Multiple regression analysis found that only nocturnal TIR was obviously related to the severity of albuminuria. In our study, eGFR was significantly associated with the number of hypoglycemic events.

CONCLUSIONS

In T2DM patients, TIR and nocturnal TIR is associated with the presence of albuminuria independent of HbA1c and GV metrics. Nocturnal TIR shows better correlation than TIR. The role of TIR especially nocturnal TIR in the evaluation of diabetes kidney disease should be emphasized.

Genetic susceptibility to diabetic kidney disease is linked to promoter variants of XOR

The lifetime risk of kidney disease in people with diabetes is 10-30%, implicating genetic predisposition in the cause of diabetic kidney disease (DKD). Here we identify an expression quantitative trait loci (QTLs) in the cis-acting regulatory region of the xanthine dehydrogenase, or xanthine oxidoreductase (Xor), a binding site for C/EBPβ, to be associated with diabetes-induced podocyte loss in DKD in male mice. We examine mouse inbred strains that are susceptible (DBA/2J) and resistant (C57BL/6J) to DKD, as well as a panel of recombinant inbred BXD mice, to map QTLs. We also uncover promoter XOR orthologue variants in humans associated with high risk of DKD. We introduced the risk variant into the 5'-regulatory region of XOR in DKD-resistant mice, which resulted in increased Xor activity associated with podocyte depletion, albuminuria, oxidative stress and damage restricted to the glomerular endothelium, which increase further with type 1 diabetes, high-fat diet and ageing. Therefore, differential regulation of Xor contributes to phenotypic consequences with diabetes and ageing.

Urine-Based Detection of Biomarkers Indicative of Chronic Kidney Disease in a Patient Cohort from Ghana

Chronic kidney disease (CKD) is a global health burden with a continuously increasing prevalence associated with an increasing incidence of diabetes and hypertension in aging populations. CKD is characterized by low glomerular filtration rate (GFR) and other renal impairments including proteinuria, thus implying that multiple factors may contribute to the etiology this disease. While there are indications of ethnic differences, it is hard to disentangle these from confounding social factors. Usually, CKD is detected in later stages of the disease when irreversible renal damage has already occurred, thus suggesting a need for early non-invasive diagnostic markers. In this study, we explored the urine secretome of a CKD patient cohort from Ghana with 40 gender-matched patients and 40 gender-matched healthy controls employing a kidney injury and a more general cytokine assay. We identified panels of kidney-specific cytokine markers, which were also gender-specific, and a panel of gender-independent cytokine markers. The gender-specific markers are IL10 and MME for male and CLU, RETN, AGER, EGFR and VEGFA for female. The gender-independent cytokine markers were APOA1, ANGPT2, C5, CFD, GH1, ICAM1, IGFBP2, IL8, KLK4, MMP9 and SPP1 (up-regulated) and FLT3LG, CSF1, PDGFA, RETN and VEGFA (down-regulated). APOA1-the major component of HDL particles-was up-regulated in Ghanaian CKD patients and its co-occurrence with APOL1 in a subpopulation of HDL particles may point to specific CKD-predisposing APOL1 haplotypes in patients of African descent-this, however, needs further investigation. The identified panels, though preliminary, lay down the foundation for the development of robust CKD-diagnostic assays.

Evaluation of continuous glucose monitoring-derived person-specific HbA1c in the presence and absence of complications in type 1 diabetes

AIM

To evaluate the accuracy of a novel kinetic model at predicting HbA1c in a real-world setting and to understand and explore the role of diabetes complications in altering the glucose-HbA1c relationship and the mechanisms involved.

MATERIALS AND METHODS

Deidentified HbA1c and continuous glucose monitoring values were collected from 93 individuals with type 1 diabetes. Person-specific kinetic variables were used, including red blood cell (RBC) glucose uptake and lifespan, to characterize the relationship between glucose levels and HbA1c. The resulting calculated HbA1c (cHbA1c) was compared with glucose management indicator (GMI) for prospective agreement with laboratory HbA1c.

RESULTS

The cohort (42 men and 51 women) had a median age (IQR) of 61 (43, 72) years and a diabetes duration of 21 (10, 33) years. A total of 24 459 days of continuous glucose monitoring (CGM) data were available and 357 laboratory HbA1c were used to assess the average glucose-HbA1c relationship. cHbA1c had a superior correlation with laboratory HbA1c compared with GMI with a mean absolute deviation of 1.7 and 6.7 mmol/mol, r²  = 0.85 and 0.44, respectively. The fraction within 10% of absolute relative deviation from laboratory HbA1c was 93% for cHbA1c and 63% for GMI. Macrovascular disease had no effect on the model's accuracy, whereas microvascular complications resulted in a trend towards higher HbA1c, secondary to increased RBC glucose uptake.

CONCLUSIONS

cHbA1c, which takes into account RBC glucose uptake and lifespan, accurately reflects laboratory HbA1c in a real-world setting and can aid in the management of individuals with diabetes.

Emerging drugs for the treatment of diabetic nephropathy

INTRODUCTION

Diabetic nephropathy remains a significant economic and social burden on both the individual patient and health-care systems as the prevalence of diabetes increases in the general population. The complex pathophysiology of diabetic kidney disease poses a challenge in the development of effective medical treatments for the disease. However, the multiple facets of diabetic nephropathy also offer a variety of potential strategies to manage this condition.

AREAS COVERED

We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat diabetic nephropathy.

EXPERT OPINION

RAAS blockers have remained the mainstay of therapy for DM nephropathy for many years, with only recent advancements with SGLT2 inhibitors and nonsteroidal MRAs. Better understanding of the long-term renal effects of ambient hyperglycemia, ranging from hemodynamic changes to increased production of oxidative and pro-inflammatory substances, has evolved our approach to the treatment of diabetic nephropathy. With continuing research for new therapeutics as well as combination therapy, the medical community may be able to better ease the burden of diabetic kidney disease.

Use of Glucose-Lowering Agents in Diabetes and CKD

Diabetes is the most common cause of kidney failure worldwide. Patients with diabetes and chronic kidney disease (CKD) are also at markedly higher risk of cardiovascular disease, particularly heart failure (HF), and death. Through the processes of gluconeogenesis and glucose reabsorption, the kidney plays a central role in glucose homeostasis. Insulin resistance is an early alteration observed in CKD, worsened by the frequent presence of hypertension, obesity, and ongoing chronic inflammation, and oxidative stress. Management of diabetes in moderate to severe CKD warrants special consideration because of changes in glucose and insulin homeostasis and altered metabolism of glucose-lowering therapies. Kidney failure and initiation of kidney replacement therapy by dialysis adds to management complexity by further limiting therapeutic options, and predisposing individuals to hypoglycemia and hyperglycemia. Glycemic goals should be individualized, considering CKD severity, presence of macrovascular and microvascular complications, and life expectancy. A general hemoglobin A1c (HbA1c) goal of approximately 7% may be appropriate in earlier stages of CKD, with more relaxed targets often appropriate in later stages. Use of sodium glucose cotransporter2 (SGLT2) inhibitors and glucagon like peptide-1 receptor agonists (GLP-1RAs) meaningfully improves kidney and heart outcomes for patients with diabetes and CKD, irrespective of HbA1c targets, and are now part of guideline-directed medical therapy in this high-risk population. Delivery of optimal care for patients with diabetes and CKD will require collaboration across health care specialties and disciplines.

Diabetic Kidney Disease: From Pathogenesis to Novel Treatment Possibilities

One of the microvascular complications of diabetes is diabetic kidney disease (DKD), often leading to end stage renal disease (ESRD) in which patients require costly dialysis or transplantation. The silent onset and irreversible progression of DKD are characterized by a steady decline of the estimated glomerular filtration rate, with or without concomitant albuminuria. The diabetic milieu allows the complex pathophysiology of DKD to enter a vicious cycle by inducing the synthesis of excessive amounts of reactive oxygen species (ROS) causing oxidative stress, inflammation, and fibrosis. As no cure is available, intensive research is required to develop novel treatments possibilities. This chapter provides an overview of the important pathomechanisms identified in diabetic kidney disease, the currently established therapies, as well as recently developed novel therapeutic strategies in DKD.

A simplified prediction model for end-stage kidney disease in patients with diabetes

This study aimed to develop a simplified model for predicting end-stage kidney disease (ESKD) in patients with diabetes. The cohort included 2549 individuals who were followed up at Kyushu University Hospital (Japan) between January 1, 2008 and December 31, 2018. The outcome was a composite of ESKD, defined as an eGFR < 15 mL min⁻¹ [1.73 m]⁻², dialysis, or renal transplantation. The mean follow-up was 5.6 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\pm$$\end{document}± 3.7 years, and ESKD occurred in 176 (6.2%) individuals. Both a machine learning random forest model and a Cox proportional hazard model selected eGFR, proteinuria, hemoglobin A1c, serum albumin levels, and serum bilirubin levels in a descending order as the most important predictors among 20 baseline variables. A model using eGFR, proteinuria and hemoglobin A1c showed a relatively good performance in discrimination (C-statistic: 0.842) and calibration (Nam and D’Agostino \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\chi$$\end{document}χ² statistic: 22.4). Adding serum albumin and bilirubin levels to the model further improved it, and a model using 5 variables showed the best performance in the predictive ability (C-statistic: 0.895, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\chi$$\end{document}χ² statistic: 7.7). The accuracy of this model was validated in an external cohort (n = 5153). This novel simplified prediction model may be clinically useful for predicting ESKD in patients with diabetes.

Clin-Star corner: What is new at the interface of geriatrics and nephrology?

Chronic kidney disease (CKD) is prevalent and burdensome among older adults in the United States. CKD affects at least 15% of the US population, and adults over 65 comprise the largest subset within this group. In this special article, we highlight key findings of three recent original investigations in nephrology and describe each study, relevance to the care of older adults, and current areas of uncertainty that warrant further investigation. Articles relate to removal of the race adjustment in the estimation of kidney function, the use of novel therapeutics to halt CKD progression and improve cardiovascular outcomes, and medication management for short-term pain control in CKD.

Making an impact on kidney disease in people with type 2 diabetes: the importance of screening for albuminuria

Albuminuria is useful for early screening and diagnosis of kidney impairment, especially in people with pre-diabetes or type 2 diabetes (T2D), which is the leading cause of chronic kidney disease (CKD) and end-stage kidney disease (ESKD), associated with increased mortality, poor cardiovascular outcomes, and high economic burden. Identifying patients with CKD who are most likely to progress to ESKD permits timely implementation of appropriate interventions. The early stages of CKD are asymptomatic, which means identification of CKD relies on routine assessment of kidney damage and function. Both albuminuria and estimated glomerular filtration rate are measures of kidney function. This review discusses albuminuria as a marker of kidney damage and cardiorenal risk, highlights the importance of early screening and routine testing for albuminuria in people with T2D, and provides new insights on the optimum management of CKD in T2D using albuminuria as a target in a proposed algorithm. Elevated urine albumin can be used to detect CKD in people with T2D and monitor its progression; however, obstacles preventing early detection exist, including lack of awareness of CKD in the general population, poor adherence to clinical guidelines, and country-level variations in screening and treatment incentives. With albuminuria being used as an entry criterion and a surrogate endpoint for kidney failure in clinical trials, and with novel treatment interventions available to prevent CKD progression, there is an urgent need for early screening and diagnosis of kidney function decline in people with T2D or pre-diabetes.

Comparing Multiple Linear Regression and Machine Learning in Predicting Diabetic Urine Albumin-Creatinine Ratio in a 4-Year Follow-Up Study

The urine albumin-creatinine ratio (uACR) is a warning for the deterioration of renal function in type 2 diabetes (T2D). The early detection of ACR has become an important issue. Multiple linear regression (MLR) has traditionally been used to explore the relationships between risk factors and endpoints. Recently, machine learning (ML) methods have been widely applied in medicine. In the present study, four ML methods were used to predict the uACR in a T2D cohort. We hypothesized that (1) ML outperforms traditional MLR and (2) different ranks of the importance of the risk factors will be obtained. A total of 1147 patients with T2D were followed up for four years. MLR, classification and regression tree, random forest, stochastic gradient boosting, and eXtreme gradient boosting methods were used. Our findings show that the prediction errors of the ML methods are smaller than those of MLR, which indicates that ML is more accurate. The first six most important factors were baseline creatinine level, systolic and diastolic blood pressure, glycated hemoglobin, and fasting plasma glucose. In conclusion, ML might be more accurate in predicting uACR in a T2D cohort than the traditional MLR, and the baseline creatinine level is the most important predictor, which is followed by systolic and diastolic blood pressure, glycated hemoglobin, and fasting plasma glucose in Chinese patients with T2D.

The 2021-2022 position of Brazilian Diabetes Society on diabetic kidney disease (DKD) management: an evidence-based guideline to clinical practice. Screening and treatment of hyperglycemia, arterial hypertension, and dyslipidemia in the patient with DKD

BACKGROUND

Diabetic kidney disease is the leading cause of end-stage renal disease and is associated with increased morbidity and mortality. This review is an authorized literal translation of part of the Brazilian Diabetes Society (SBD) Guidelines 2021-2022. This evidence-based guideline provides guidance on the correct management of Diabetic Kidney Disease (DKD) in clinical practice.

METHODS

The methodology was published elsewhere in previous SBD guidelines and was approved by the internal institutional Steering Committee for publication. Briefly, the Brazilian Diabetes Society indicated 14 experts to constitute the Central Committee, designed to regulate methodology, review the manuscripts, and make judgments on degrees of recommendations and levels of evidence. SBD Renal Disease Department drafted the manuscript selecting key clinical questions to make a narrative review using MEDLINE via PubMed, with the best evidence available including high-quality clinical trials, metanalysis, and large observational studies related to DKD diagnosis and treatment, by using the MeSH terms [diabetes], [type 2 diabetes], [type 1 diabetes] and [chronic kidney disease].

RESULTS

The extensive review of the literature made by the 14 members of the Central Committee defined 24 recommendations. Three levels of evidence were considered: A. Data from more than 1 randomized clinical trial or 1 metanalysis of randomized clinical trials with low heterogeneity (I2 < 40%). B. Data from metanalysis, including large observational studies, a single randomized clinical trial, or a pre-specified subgroup analysis. C: Data from small or non-randomized studies, exploratory analyses, or consensus of expert opinion. The degree of recommendation was obtained based on a poll sent to the panelists, using the following criteria: Grade I: when more than 90% of agreement; Grade IIa 75-89% of agreement; IIb 50-74% of agreement, and III, when most of the panelist recommends against a defined treatment.

CONCLUSIONS

To prevent or at least postpone the advanced stages of DKD with the associated cardiovascular complications, intensive glycemic and blood pressure control are required, as well as the use of renin-angiotensin-aldosterone system blocker agents such as ARB, ACEI, and MRA. Recently, SGLT2 inhibitors and GLP1 receptor agonists have been added to the therapeutic arsenal, with well-proven benefits regarding kidney protection and patients' survival.

Heterogeneity in the association between prediabetes categories and reduction on glomerular filtration rate in a 5-year follow-up

Prediabetes and not just diabetes can cause kidney damage. This study assess the association of prediabetes with development of impaired renal function (IRF). We used data from PREDAPS prospective study a cohort of 1072 subjects with prediabetes and another cohort of 772 subjects without prediabetes were follow-up from 2012 to 2017. Prediabetes was defined according to American Association of Diabetes criteria. IRF was defined as having a glomerular filtration rate < 60 mL/min/1.73 m2. Incidence rates of IRF in both cohorts and in different categories of prediabetes, based on impaired glycosylated hemoglobin (HbA1c) and/or fasting plasma glucose (FPG), were calculated. Hazard ratios (HR) for the association of the prediabetes with IRF, adjusting for potential confounders, were estimated by Cox regression models. Incidence rates of IRF per 100 person-years were 1.72 (95% confidence interval [CI]: 1.34-2.21) and 1.79 (95%CI: 1.45-2.20) for those without and with prediabetes, respectively .The HR of IRF in subjects with prediabetes with respect to subjects without prediabetes was 0.76 (95% CI: 0. 54-1.07). Corresponding HRs for type of prediabetes was 0.68 (95%CI: 0.40-1.15) for those with both altered parameters, 0.68 (95%CI: 00.40-1.15) for those with only impaired HbA1c and 1.12 (95%CI: 0.68-1.85) for those with only impaired FPG. The present study reflects an overall trend towards a slightly decreased risk of IRF onset associated to prediabetes except for individuals with only isolated impaired FPG. Further studies are warranted to fully assess the renal progression of each group.

Continuous Glucose Monitoring metrics in the Assessment of Glycemia in Moderate-to-Advanced Chronic Kidney Disease (CKD) in Diabetes

Introduction

Glycated hemoglobin A1c (HbA1c) has reduced reliability in advanced chronic kidney disease (CKD) owing to factors influencing red cell turnover. Recent guidelines support the use of continuous glucose monitoring (CGM) in glycemic assessment in these patients. We evaluated relationships between HbA1c and CGM metrics of average glycemia and glucose variability (GV) in moderate-to-advanced CKD.

Methods

There were a total of 90 patients with diabetes in CKD stages G3b (n = 33), G4 (n = 43), and G5 (nondialysis) (n = 14) (age [mean ± SD] 65.4 ± 9.0 years, estimated glomerular filtration rate [eGFR] 26.1 ± 9.6 ml/min per 1.73 m², and HbA1c 7.4 ± 0.8%). CGM metrics were estimated from blinded CGM (Medtronic Ipro2 with Enlite sensor) and compared with HbA1c in the same week.

Results

Correlations between glucose management indicator (GMI) and HbA1c attenuated with advancing CKD (G3b [r = 0.68, P < 0.0001], G4 [r = 0.52, P < 0.001], G5 [r = 0.22, P = 0.44], P = 0.01 for CKD stage). In G3b and G4, HbA1c correlated significantly with time-in-range (TIR) (3.9–10.0 mmol/l) (r = −0.55 and r = −0.54, respectively) and % time > 13.9 mmol/l (r = 0.53 and r = 0.44, respectively), but not in G5. HbA1c showed no correlation with % time <3.0 mmol/l (r = −0.045, P = 0.67) or % coefficient of variation (CV) (r = −0.05, P = 0.64) in any CKD stage. Only eGFR was a significant determinant of bias for the difference between GMI and HbA1c (difference −0.28%, 95% CI [−0.52 to −0.03] per 15 ml/min per 1.73 m² decrement, P = 0.03).

Conclusion

CGM-derived indices might serve as an adjunct to HbA1c monitoring to guide glycemic management, especially in those with eGFR <30 ml/min per 1.73 m². Time in hypoglycemia and glycemic variability are relevant glycemic targets for optimization not reflected by HbA1c.

Joint 30-year HbA1c and lipid trajectories and mortality in type 1 diabetes

AIMS

Higher HbA1c has been associated with dyslipidemia in type 1 diabetes, but it is unknown whether there is heterogeneity in this association. Thus we assessed the longitudinal association between HbA1c and lipids over 30 years in a type 1 diabetes cohort and examined whether variation in such longitudinal patterns was associated with total and cause-specific mortality.

METHODS

Data were from the Pittsburgh Epidemiology of Diabetes Complications study (n = 581 with ≥2 visits, 51% male, baseline mean age 27, diabetes duration 19 years). Longitudinal associations between HbA1c and lipids were assessed in mixed models. Group-based multi-trajectory models identified simultaneous trajectories of HbA1c and lipids.

RESULTS

Longitudinal HbA1c was associated with Non-HDLc (p < 0.0001) and triglycerides (p < 0.0001), but not HDLc (men: p = 0.72, women: p = 0.76). There was heterogeneity in the HbA1c-Non-HDLc association only, with five HbA1c-Non-HDLc groups identified. One group (20%) had an unexpected combination of high HbA1c but normal Non-HDLc and had only moderately increased cardiovascular mortality (rate ratio [RR] = 2.80, 95% CI 1.31-6.00) and kidney disease mortality (RR = 2.30, 95% CI 0.97-5.50) compared to Low HbA1c-Normal Non-HDLc.

CONCLUSIONS

These results suggest there is a subgroup with type 1 diabetes who, despite poor glycemic control, has a relatively good prognosis, perhaps related to good Non-HDLc.

Plasma advanced glycation end products and the subsequent risk of microvascular complications in type 1 diabetes in the DCCT/EDIC

INTRODUCTION

To assess impact of glycemic control on plasma protein-bound advanced glycation end products (pAGEs) and their association with subsequent microvascular disease.

RESEARCH DESIGN AND METHODS

Eleven pAGEs were measured by liquid chromatography-mass spectrometry in banked plasma from 466 participants in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study at three time points (TPs): DCCT year 4 (TP1) and year 8 (TP2) and EDIC year 5/6 (TP3). Correlation coefficients assessed cross-sectional associations, and Cox proportional hazards models assessed associations with subsequent risk of microvascular complications through EDIC year 24.

RESULTS

Glucose-derived glycation products fructose-lysine (FL), glucosepane (GSPN) and carboxymethyl-lysine (CML) decreased with intensive glycemic control at both TP1 and TP2 (p<0.0001) but were similar at TP3, and correlated with hemoglobin A1c (HbA1c). At TP1, the markers were associated with the subsequent risk of several microvascular outcomes. These associations did not remain significant after adjustment for HbA1c, except methionine sulfoxide (MetSOX), which remained associated with diabetic kidney disease. In unadjusted models using all 3 TPs, glucose-derived pAGEs were associated with subsequent risk of proliferative diabetic retinopathy (PDR, p<0.003), clinically significant macular edema (CSME, p<0.015) and confirmed clinical neuropathy (CCN, p<0.018, except CML, not significant (NS)). Adjusted for age, sex, body mass index, diabetes duration and mean updated HbA1c, the associations remained significant for PDR (FL: p<0.002, GSPN: p≤0.02, CML: p<0.003, pentosidine: p<0.02), CMSE (CML: p<0.03), albuminuria (FL: p<0.02, CML: p<0.03) and CCN (FL: p<0.005, GSPN : p<0.003).

CONCLUSIONS

pAGEs at TP1 are not superior to HbA1c for risk prediction, but glucose-derived pAGEs at three TPs and MetSOX remain robustly associated with progression of microvascular complications in type 1 diabetes even after adjustment for HbA1c and other factors.

Implementation of corneal confocal microscopy for screening and early detection of diabetic neuropathy in primary care alongside retinopathy screening: Results from a feasibility study

OBJECTIVE

Screening for diabetic peripheral neuropathy (DPN) is essential for early detection and timely intervention. Quantitative assessment of small nerve fiber damage is key to the early diagnosis and assessment of its progression. Corneal confocal microscopy (CCM) is a non-invasive, in-vivo diagnostic technique that provides an accurate surrogate biomarker for small-fiber neuropathy. In this novel study for the first time, we introduced CCM to primary care as a screening tool for DPN alongside retinopathy screening to assess the level of neuropathy in this novel cohort.

RESEARCH DESIGN AND METHODS

450 consecutive subjects with type 1 or type 2 diabetes attending for annual eye screening in primary care optometry settings underwent assessment with CCM to establish the prevalence of sub-clinical diabetic peripheral neuropathy. Subjects underwent assessment for neurological and ocular symptoms of diabetes and a history of diabetic foot disease, neuropathy and diabetic retinopathy (DR).

RESULTS

CCM examination was completed successfully in 427 (94.9%) subjects, 22% of whom had neuropathy according to Diabetic Neuropathy Symptom (DNS) score. The prevalence of sub-clinical neuropathy as defined by abnormal corneal nerve fiber length (CNFL) was 12.9%. In the subjects with a short duration of type 2 diabetes, 9.2% had abnormal CNFL. CCM showed significant abnormalities in corneal nerve parameters in this cohort of subjects with reduction of corneal nerve fiber density (CNFD, p<0.001), CNFL (p<0.001) and corneal nerve branch density (CNBD, p<0.001) compared to healthy subjects. In subjects who had no evidence of DR (67% of all subjects), 12.0% had abnormal CNFL.

CONCLUSIONS

CCM may be a sensitive biomarker for early detection and screening of DPN in primary care alongside retinopathy screening.

Decision models in type 2 diabetes mellitus: A systematic review

AIMS

To reduce the burden of type 2 diabetes (T2DM), the disease decision model plays a vital role in supporting decision-making. Currently, there is no comprehensive summary and assessment of the existing decision models for T2DM. The objective of this review is to provide an overview of the characteristics and capabilities of published decision models for T2DM. We also discuss which models are suitable for different study demands.

MATERIALS AND METHODS

Four databases (PubMed, Web of Science, Embase, and the Cochrane Library) were electronically searched for papers published from inception to August 2020. Search terms were: "Diabetes-Mellitus, Type 2", "cost-utility", "quality-of-life", and "decision model". Reference lists of the included studies were manually searched. Two reviewers independently screened the titles and abstracts following the inclusion and exclusion criteria. If there was insufficient information to include or exclude a study, then a full-text version was sought. The extracted information included basic information, study details, population characteristics, basic modeling methodologies, model structure, and data inputs for the included applications, model outcomes, model validation, and uncertainty.

RESULTS

Fourteen unique decision models for T2DM were identified. Markov chains and risk equations were utilized by four and three models, respectively. Three models utilized both. Except for the Archimedes model, all other models (n = 13) implemented an annual cycle length. The time horizon of most models was flexible. Fourteen models had differences in the division of health states. Ten models emphasized macrovascular and microvascular complications. Six models included adverse events. Majority of the models (n = 11) were patient-level simulation models. Eleven models simulated annual changes in risk factors (body mass index, glycemia, HbA1c, blood pressure (systolic and/or diastolic), and lipids (total cholesterol and/or high-density lipoprotein)). All models reported the main data sources used to develop health states of complications. Most models (n = 11) could deal with the uncertainty of models, which were described in varying levels of detail in the primary studies. Eleven studies reported that one or more validation checks were performed.

CONCLUSIONS

The existing decision models for T2DM are heterogeneous in terms of the level of detail in the classification of health states. Thus, more attention should be focused on balancing the desired level of complexity against the required level of transparency in the development of T2DM decision models.

Renal function in patients following a low carbohydrate diet for type 2 diabetes: a review of the literature and analysis of routine clinical data from a primary care service over 7 years

PURPOSE OF REVIEW

People with T2 Diabetes (T2D) who follow a low carbohydrate diet (LCD) may increase their dietary protein intake. Dietary protein can modulate renal function so there is debate about its role in renal disease. There is concern that higher protein intakes may promote renal damage, and that LCDs themselves may impact on cardiovascular risk. We review the evidence around LCDs, renal and cardiovascular risk factors and compare to results obtained in a real-world, primary care setting.

RECENT FINDINGS

Chronic kidney disease (CKD) is a well-recognised microvascular complication of T2D caused in part by; chronically increased glomerular pressure, hyperfiltration, increased blood pressure and advanced glycation end products. Hyperglycemia can be seen as central to all of these factors. A LCD is an effective first step in its correction as we demonstrate in our real-world cohort.

SUMMARY

We found evidence that LCDs for people with T2D may improve many renal and cardiovascular risk factors. In our own LCD cohort of 143 patients with normal renal function or only mild CKD, over an average of 30 months the serum creatinine improved by a significant mean of 4.7 (14.9) μmol/L. What remains to be shown is the effect of the approach on people with T2D and moderate/severe CKD.

Renal hemodynamic effects differ between antidiabetic combination strategies: randomized controlled clinical trial comparing empagliflozin/linagliptin with metformin/insulin glargine

BACKGROUND

Type 2 diabetes causes cardio-renal complications and is treated with different combination therapies. The renal hemodynamics profile of such combination therapies has not been evaluated in detail.

METHODS

Patients (N = 97) with type 2 diabetes were randomized to receive either empagliflozin and linagliptin (E+L group) or metformin and insulin glargine (M+I group) for 3 months. Renal hemodynamics were assessed with para-aminohippuric acid and inulin for renal plasma flow (RPF) and glomerular filtration rate (GFR). Intraglomerular hemodynamics were calculated according the Gomez´ model.

RESULTS

Treatment with E+L reduced GFR (p = 0.003), but RPF remained unchanged (p = 0.536). In contrast, M+I not only reduced GFR (p = 0.001), but also resulted in a significant reduction of RPF (p < 0.001). Renal vascular resistance (RVR) decreased with E+L treatment (p = 0.001) but increased with M+I treatment (p = 0.001). The changes in RPF and RVR were different between the two groups (both p_adjust < 0.001). Analysis of intraglomerular hemodynamics revealed that E+L did not change resistance of afferent arteriole (R_A) (p = 0.116), but diminished resistance of efferent arterioles (R_E) (p = 0.001). In M+I group R_A was increased (p = 0.006) and R_E remained unchanged (p = 0.538). The effects on R_A (p_adjust < 0.05) and on R_E (p_adjust < 0.05) differed between the groups.

CONCLUSIONS

In patients with type 2 diabetes and preserved renal function treatment with M+I resulted in reduction of renal perfusion and increase in vascular resistance, in contrast to treatment with E+I that preserved renal perfusion and reduced vascular resistance. Moreover, different underlying effects on the resistance vessels have been estimated according to the Gomez model, with M+I increasing R_A and E+L predominantly decreasing R_E, which is in contrast to the proposed sodium-glucose cotransporter 2 inhibitor effects.

TRIAL REGISTRATION

The study was registered at www.clinicaltrials.gov (NCT02752113) on April 26, 2016.

Macro and microangiopathy related to retinopathy and choroidopathy in type 2 diabetes

PURPOSE

To describe the relationship between diabetic retinopathy (DR) and choroidal thickness (CT), and systemic macro and microangiopathy in patients with type 2 diabetes (T2D).

METHODS

Cross-sectional study enrolling 200 eyes (100 T2D naïve patients) without macular edema. DR was graded and swept-source optical coherence tomography Triton DRI (Topcon) was used to measure CT, which gave automatic measurements in ETDRS grid. An endocrinologist examined all the patients and searched in their medical records for data about macro and microangiopathy: ischemic cardiopathy (IC), cerebrovascular accident (CVA), peripheral artery disease (PAD), nephropathy, and peripheral polyneuropathy (PPN).

RESULTS

Mean age was 67.38 ± 8.15 years, mean axial length was 23.26 ± 0.09 mm, and mean IOP was 16.75 ± 3.06 mmHg. Sixty eyes had no DR, 46 had mild, 64 had moderate, 20 had severe, and 10 had proliferative DR. IC was correlated with horizontal choroidal zones (p < 0.05 and η between 0.16 and 0.21) but not with DR (p = 0.16). CVA was neither correlated with CT (p > 0.05) nor with DR (p = 0.39). PAD was not correlated with CT (p > 0.05) but it was with DR (p = 0.03). The type of nephropathy was correlated both with CT in vertical sectors (p < 0.05 and η between 0.15 and 0.27) and DR (p = 0.01, τ = 0.24). PPN was not correlated with CT (p > 0.05) but it was with DR (p = 0.03).

CONCLUSIONS

DR is correlated with microangiopathy (nephropathy and PPN) but not with macroangiopathy (IC, CVA, and PAD). CT is mildly correlated with nephropathy and IC. Some choroidal regions are more sensitive than others to each diabetic macro and microvascular manifestation.

Laser-Assisted Surface Modification of Ni Microstructures with Au and Pt toward Cell Biocompatibility and High Enzyme-Free Glucose Sensing

We investigated the influence of morphology of Ni microstructures modified with Au and Pt on their cell biocompatibility and electrocatalytic activity toward non-enzymatic glucose detection. Synthesis and modification were carried out using a simple and inexpensive approach based on the method of laser-induced deposition of metal microstructures from a solution on the surface of various dielectrics. Morphological analysis of the fabricated materials demonstrated that the surface of the Ni electrode has a hierarchical structure with large-scale 10 μm pores and small-scale 10 nm irregularities. In turn, the Ni-Pt surface has large-scale cavities, small-scale pores (1-1.5 μm), and a few tens of nanometer particles opposite to Ni-Au that reveals no obvious hierarchical structure. These observations were supported by impedance spectroscopy confirming the hierarchy of the surface topography of Ni and Ni-Pt structures. We tested the biocompatibility of the fabricated Ni-based electrodes with the HeLa cells. It was shown that the Ni-Au electrode has a much better cell adhesion than Ni-Pt with a more complex morphology. On the contrary, porous Ni and Ni-Pt electrodes with a more developed surface area than that of Ni-Au have better catalytic performance toward enzymeless glucose sensing, revealing greater sensitivity, selectivity, and stability. In this regard, modification of Ni with Pt led to the most prominent results providing rather good glucose detection limits (0.14 and 0.19 μA) and linear ranges (10-300 and 300-1500 μA) as well as the highest sensitivities of 18,570 and 2929 μA mM^-1 cm^-2. We also proposed some ideas to clarify the observed behavior and explain the influence of morphology of the fabricated electrodes on their electrocatalytic activity and biocompatibility.

Diabetic nephropathy: A twisted thread to unravel

Diabetic nephropathy (DN), a persistent microvascular problem of diabetes mellitus is described as an elevated level of albumin excretion in urine and impaired renal activity. The morbidity and mortality of type-1 diabetics and type-2 diabetics due to end stage renal disease is also a result of the increased prevalence of DN. DN typically occurs as a consequence of an association among metabolic and hemodynamic variables, activating specific pathways leading to renal injury. According to current interventions, intensive glucose regulation decreases the threat of DN incidence and growth, and also suppressing the renin-angiotensin system (RAS) is a significant goal for hemodynamic and metabolism-related deformities in DN. However, the pathogenesis of DN is multifactorial so novel approaches other than glucose and blood pressure control are required for treatment. This review briefly summarizes the reported pathogenesis of DN, current interventions for its treatment, and possible novel interventions to unweave the thread of DN.

Hub Genes Associated with the Diagnosis of Diabetic Retinopathy

Purpose

This study aimed to identify genes that may be effective in diagnosing or treating diabetic retinopathy (DR), the most common complication of diabetes mellitus (DM).

Methods

Differentially expressed genes (DEGs) were identified between DR and DM in GSE146615 dataset. DEGs that were consistently up- or down-regulated under both standard glucose and high glucose conditions were identified as common genes and used to generate a protein-protein interaction network and modules. The module genes were assessed for the area under the receiver operating characteristic curve (AUC), leading to the identification of hub genes. Differentially methylated probes in GSE76169 were also compared with common DEGs to identify specific methylation markers of DR. Enrichment analysis was used to explore the biological characteristics. The Short Time-series Expression Miner algorithm was used to identify genes that were progressively dysregulated in the sequence: healthy controls < DM < DR.

Results

A total of 1917 common genes were identified for seven modules. The eight genes with AUC > 0.8 under high glucose and standard glucose conditions were considered as hub genes. The module genes were significantly enriched during vascular smooth muscle cell development and regulation of oxygen metabolism, while 92 methylation markers were involved in the similar terms. Among the progressively dysregulated genes, three intersection genes under both standard glucose and high glucose conditions were found to be module genes and were considered as key genes.

Conclusion

We identified eight potential DR-specific diagnostic and therapeutic genes, whose abnormal expression can cause oxidative stress, thus favoring the course of the disease.