Prevalence of non-diabetic renal disease among African-American patients with type II diabetes mellitus

Non-diabetic Kidney Disease in Diabetic Population: A Single-Center Study From South India

Introduction: Diabetic kidney disease (DKD) is the commonest cause of chronic kidney disease and end-stage kidney disease worldwide, consequently it has become an important productive implication to the healthcare system. This study was conducted to assess the prevalence of non-DKD (NDKD) in diabetic patients from south India.

Objective: To assess the prevalence of NDKD in type 2 diabetes mellitus patients presenting to a tertiary care hospital from south India and also to analyze clinical clues to establish a diagnosis of NDKD.

Patient and methods: It is a retrospective observational study of analyzing patient characteristics and renal biopsies. All Diabetic patients with a clinical suspicion of non-diabetic kidney disease who underwent renal biopsy during the study period between January 2012 and June 2017 were included. Based on the biopsy findings, the patients were classified into three groups (isolated diabetic nephropathy, isolated NDKD, and NDKD with underlying diabetic nephropathy) and patients’ characteristics were compared between the groups for analysis.

Results: A total of 236 renal biopsies were analyzed for the study. Of that, 114 had features of DKD, 78 NDKD with diabetic nephropathy (DN) and 44 had isolated NDKD. Acute interstitial nephritis was the most common cause of NDKD.

Conclusion: From the current study, the long duration of diabetes mellitus beyond five years and hypertension beyond two years reasonably predict DKD.

Manifestation of rs1888747 polymorphisms in the FRMD3 gene in diabetic kidney disease and diabetic retinopathy in type 2 diabetes patients

Background

FRMD3 polymorphisms has suggested that they could be an alternative test to differentiate diabetic nephropathy (DN) from nondiabetic renal disease (NDRD) in type 2 diabetes mellitus (DM) patients. This study was performed to investigate the relationship between the FRMD3 gene and clinical characteristics of DN.

Methods

Patients who already had renal pathologic results were tested for FRMD3 polymorphisms. The subjects were classified into three groups; DN with diabetic retinopathy (DR), DN without DR, and DM with NDRD. FRMD3 polymorphisms were analyzed in each group.

Results

The prevalence of GG, CG, and CC was 44.4%, 42.2%, and 13.3% respectively. There was no significant difference in clinical parameters, which consisted of disease duration, proteinuria, and complications in DN with or without DR and DM with NDRD. The G allele was mainly found in DN with DR patients (50.8%) whereas the C allele was found in DM with NDRD patients (43.5%) (p = 0.02). There was a significant association between the CC genotype in NDRD when compared to GG (p = 0.001). In addition, the C allele was 2.10-fold more often associated with NDRD than the G allele (p = 0.03). The CC genotype was correlated with risk for NDRD than the GG and GC genotypes, with odds ratios of 6.89 and 4.91, respectively (p = 0.02).

Conclusion

C allele presentation, especially homozygous CC, was associated with NDRD pathology in patients with overt proteinuria. Hence, kidney biopsy is suggested in those with the C allele or homozygous CC genotype, regardless of retinopathy manifestations.

Histopathologic and Clinical Features in Patients with Diabetes and Kidney Disease

BACKGROUND

The discovery of nondiabetic kidney disease (NDKD) in an individual patient with diabetes may have significant treatment implications. Extensive histopathologic data in this population are lacking, but they may provide insights into the complex pathogenesis of diabetic nephropathy (DN) and reveal specific phenotypes for the development of targeted therapies. This study seeks to elucidate the clinical and laboratory parameters associated with the spectrum of kidney histopathologic features in patients with diabetes.

METHODS

This study is a retrospective analysis of 399 kidney biopsies assessed from 2014 to 2016 at the University of Washington among patients with diabetes. More comprehensive clinical data were evaluated in a subset of 79 participants.

RESULTS

Of the 399 biopsies reviewed, 192 (48%) had a primary diagnosis of DN (including 26 with an additional diagnosis), and 207 (52%) had a primary diagnosis of NDKD (including 67 who also had DN). Retinopathy (sensitivity: 0.86; specificity: 0.81; OR, 27.1; 95% CI, 6.8 to 107.7) and higher levels of proteinuria (7.6 versus 4.1 g/d; P=0.004) were associated with DN, whereas a physician description of AKI was associated with a lower risk of DN (OR, 0.13; 95% CI, 0.04 to 0.38). The four most prevalent diagnoses in participants with NDKD were FSGS in 39, nephrosclerosis in 29, IgA nephropathy in 27, and acute tubular injury in 21.

CONCLUSIONS

Among patients with diabetes who undergo kidney biopsy in the Pacific Northwest, approximately half have DN, and half have NDKD. Retinopathy and more severe proteinuria were associated with DN, and AKI was a more common descriptor in NDKD.Podcast: This article contains a podcast at https://www.asnonline.org/media/podcast/K360/2020_11_25_KID0003962020.mp3.

Insights into the Role of Renal Biopsy in Patients with T2DM: A Literature Review of Global Renal Biopsy Results

INTRODUCTION

Renal biopsy performed in patients with type 2 diabetes mellitus (T2DM) for atypical or suspected diabetic kidney disease (DKD) reveals one of three possibilities: diabetic nephropathy (DN, pathological diagnosis of DKD), nondiabetic kidney disease (NDKD) and DN plus NDKD (mixed form). NDKD (including the mixed form) is increasingly being recognized worldwide. With the emerging concept of DKD and the complexity of routine application of renal biopsy, the identification of "clinical indicators" to differentiate DKD from NDKD has been an area of active research.

METHODS

The PubMed database was searched for relevant articles mainly according to the keyword search method. We reviewed prevalence of the three types of DKD and different pathological lesions of NDKD. We also reviewed the clinical indicators used to identify DKD and NDKD.

RESULTS

The literature search identified 40 studies (5304 data) worldwide between 1977 and 2019 that looked at global renal biopsy and pathological NDKD lesions. The overall prevalence rate of DN, NDKD and DN plus NDKD is reported to be 41.3, 40.6 and 18.1%, respectively. In Asia, Africa (specifically Morocco and Tunisia) and Europe, the most common isolated NDKD pathological type is membranous nephropathy, representing 24.1, 15.1 and 22.6% of cases, respectively. In contrast, focal segmental glomerulosclerosis is reported to be the primary pathological type in North America (specifically the USA) and Oceania (specifically New Zealand), representing 22% and 63.9% of cases, respectively. Tubulointerstitial disease accounts for a high rate in the mixed group (21.7%), with acute interstitial nephritis being the most prevalent (9.3%), followed by acute tubular necrosis (9.0%). Regarding clinical indicators to differentiate DKD from NDKD, a total of 14 indicators were identified included in 42 studies. Among these, the most commonly studied indicators included diabetic retinopathy, duration of diabetes, proteinuria and hematuria. Regrettably, indicators with high sensitivity and specificity have not yet been identified.

CONCLUSION

To date, renal biopsy is still the gold standard to diagnose diabetes complicated with renal disease, especially when T2DM patients present atypical DKD symptoms (e.g. absence of diabetic retinopathy, shorter duration of diabetes, microscopic hematuria, sub-nephrotic range proteinuria, lower glycated hemoglobin, lower fasting blood glucose). We conclude that renal biopsy as early as possible is of great significance to enable personalized treatment to T2DM patients.

Potential value of three-dimensional ultrasonography in diagnosis of diabetic nephropathy in Chinese diabetic population with kidney injury

Background

To explore the potential value of three-dimensional ultrasonography (3DUS) and contrast-enhanced ultrasound (CEUS) in the diagnosis of diabetic nephropathy (DN) in Chinese diabetic patients with kidney injury.

Methods

Patients with type 2 diabetes mellitus and kidney injury in our hospital were enrolled, and the clinical characteristics as well as the laboratory data of patients were collected; 3DUS and CEUS were used to evaluate the morphological structure and blood perfusion of kidneys. Eligible patients were categorized into two groups based on renal biopsy results: DN group and non-diabetic renal diseases (NDRD) group. Correlation analysis and logistic regression analysis were applied to identify the risk factors of DN development.

Results

A total of 115 patients aged from 24 to 78 years old were recruited in the experiment, of which 64 patients (55.65%) and 51 patients (44.35%) were in the DN group and NDRD group, respectively. After correction to CKD stage, BMI and right kidney volume index were retained to identify patients with DN. The ROC of the logistic regression model had an AUC of 0.703 (95% CI: 0.591–0.815) and it was higher than both indicators.

Conclusion

3DUS has potential value in the diagnosis of diabetic nephropathy in Chinese diabetic population with kidney injury and may act as an auxiliary diagnosis for DN. More prospective and well-designed studies with larger samples are needed to verify the result.

CKD in diabetes: diabetic kidney disease versus nondiabetic kidney disease

The increasing global prevalence of type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) has prompted research efforts to tackle the growing epidemic of diabetic kidney disease (DKD; also known as diabetic nephropathy). The limited success of much of this research might in part be due to the fact that not all patients diagnosed with DKD have renal dysfunction as a consequence of their diabetes mellitus. Patients who present with CKD and diabetes mellitus (type 1 or type 2) can have true DKD (wherein CKD is a direct consequence of their diabetes status), nondiabetic kidney disease (NDKD) coincident with diabetes mellitus, or a combination of both DKD and NDKD. Preclinical studies using models that more accurately mimic these three entities might improve the ability of animal models to predict clinical trial outcomes. Moreover, improved insights into the pathomechanisms that are shared by these entities - including sodium-glucose cotransporter 2 (SGLT2) and renin-angiotensin system-driven glomerular hyperfiltration and tubular hyper-reabsorption - as well as those that are unique to individual entities might lead to the identification of new treatment targets. Acknowledging that the clinical entity of CKD plus diabetes mellitus encompasses NDKD as well as DKD could help solve some of the urgent unmet medical needs of patients affected by these conditions.

Diagnostic Performance of Retinopathy in the Detection of Diabetic Nephropathy in Type 2 Diabetes: A Systematic Review and Meta-Analysis of 45 Studies

AIMS

To conduct an evidence-based evaluation of diabetic retinopathy (DR) for the diagnosis of diabetic nephropathy (DN) in type 2 diabetics with kidney disease.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Library from inception to June 27, 2018, including the reference lists of identified primary studies. A study was included if it (1) used DR as a diagnostic test for DN; and (2) used histological evaluation of renal tissues as the reference standard.

RESULTS

The analysis included 45 studies (4,561 patients). A bivariate analysis yielded a sensitivity of 0.67 (95% CI 0.61-0.74) and a specificity of 0.78 (95% CI 0.73-0.82). The summary receiver operating characteristic curve analysis provided an area under the curve (AUC) of 0.79 (95% CI 0.76-0.83). In a setting of 41% prevalence of DN, the probability of DN would be 68% if the test of DR was positive, and the probability of DN would be 23% if it was negative. In addition, although the mean specificity of proliferative DR for the detection of DN was 0.99 (95% CI 0.45-1.00), the mean sensitivity was 0.34 (95% CI 0.24-0.44), and the AUC was 0.58 (95% CI 0.53-0.62).

CONCLUSIONS

DR is helpful in diagnosing DN in persons with type 2 diabetes and kidney disease, but the severity of DR may not parallel the presence of DN.

Meta-Analysis of Diagnostic Accuracy of Retinopathy for the Detection of Diabetic Kidney Disease in Adults With Type 2 Diabetes

OBJECTIVES

The study aimed to explore whether diabetic retinopathy (DR) could distinguish diabetic kidney disease (DKD) from nondiabetic renal diseases (NDRDs) in patients with type 2 diabetes mellitus and renal disease.

METHODS

We searched PubMed, Embase, Cochrane, MEDLINE and China National Knowledge Internet for articles that enrolled patients with DKD and NDRD. The results were summarized as sensitivity, specificity and the area under the curve of summary receiver operating characteristic curve with their 95% confidence intervals (CIs).

RESULTS

A total of 51 studies that included 4,990 participants were collected for evaluation. The overall pooled sensitivity, specificity and area under the curve with their 95% CIs were 0.67 (95% CI 0.61, 0.73), 0.77 (95% CI 0.72, 0.81) and 0.78 (95% CI 0.75 to 0.82), respectively. If the test for DR is negative, the probability of DKD would decrease to 10%, but if the test for DR is positive, the probability would increase only to 42%. In addition, although the mean specificity of proliferative DR for detection of DKD was 0.98 (95% CI 0.92 to 1.00), the mean sensitivity was 0.25 (95% CI 0.16, 0.35).

CONCLUSIONS

DR may lack adequate evidence either to verify DKD or to exclude NDRD, and the severity of DR may not parallel the presence of DKD.

Glomerular Filtration Rate and/or Ratio of Urine Albumin to Creatinine as Markers for Diabetic Retinopathy: A Ten-Year Follow-Up Study

AIMS

To determine the relationship between diabetic nephropathy and diabetic retinopathy on a population of type 2 diabetes mellitus patients.

METHODS

A prospective ten-year follow-up population-based study. We determined differences between estimated glomerular filtration rate (eGFR) using the chronic kidney disease epidemiology collaboration equation and urine albumin to creatinine ratio.

RESULTS

Annual incidence of any-DR was 8.21 ± 0.60% (7.06%-8.92%), sight-threatening diabetic retinopathy (STDR) was 2.65 ± 0.14% (2.48%-2.88%), and diabetic macular edema (DME) was 2.21 ± 0.18% (2%-2.49%). Renal study results were as follows: UACR > 30 mg/g had an annual incidence of 7.02 ± 0.05% (6.97%-7.09%), eGFR < 60 ml/min/1.73 m2 incidence was 5.89 ± 0.12% (5.70%-6.13%). Cox's proportional regression analysis of DR incidence shows that renal function studied by eGFR < 60 ml/min/1.73 m2 was less significant (p = 0.04, HR 1.223, 1.098-1.201) than UACR ≥ 300 mg/g (p < 0.001, HR 1.485, 1.103-1.548). The study of STDR shows that eGFR < 60 ml/min/1.73 m2 was significant (p = 0.02, HR 1.890, 1.267-2.820), UACR ≥ 300 mg/g (p < 0.001, HR 2.448, 1.595-3.757), and DME shows that eGFR < 60 ml/min/1.73 m2 was significant (p = 0.02, HR 1.920, 1.287-2.864) and UACR ≥ 300 mg/g (p < 0.001, HR 2.432, 1.584-3.732).

CONCLUSIONS

The UACR has a better association with diabetic retinopathy than the eGFR, although both are important risk factors for diabetic retinopathy.

Renal biopsy in patients with diabetes: a pooled meta-analysis of 48 studies

Background

The utility of renal biopsy in patients with diabetes is highly debated. Diabetics with rapidly worsening renal disease are often 'clinically' labelled as having diabetic nephropathy (DN), whereas, in many cases, they are rather developing a non-diabetic renal disease (NDRD) or mixed forms (DN + NDRD).

Methods

We performed a systematic search for studies on patients with diabetes with data on the frequency of DN, NDRD and mixed forms, and assessed the positive predictive values (PPVs) and odds ratios (ORs) for such diagnoses by meta-analysing single-study prevalence. Possible factors explaining heterogeneity among the different diagnoses were explored by meta-regression.

Results

In the 48 included studies ( n = 4876), the prevalence of DN, NDRD and mixed forms ranged from 6.5 to 94%, 3 to 82.9% and 4 to 45.5% of the overall diagnoses, respectively. IgA nephropathy was the most common NDRD (3-59%). PPVs for DN, NDRD and mixed forms were 50.1% [95% confidence interval (CI): 44.7-55.2], 36.9% (95% CI: 32.3-41.8) and 19.7% (95% CI: 16.3-23.6), respectively. The PPV when combining NDRD and mixed forms was 49.2% (95% CI: 43.8-54.5). Meta-regression identified systolic pressure, HbA1c, diabetes duration and retinopathy as factors explaining heterogeneity for NDRD, creatinine and glomerular filtration rate for mixed forms and only serum creatinine for DN. ORs of DN versus NDRD and mixed forms were 1.71 (95% CI: 1.54-1.91) and 4.1 (95% CI: 3.43-4.80), respectively.

Conclusions

NDRD are highly prevalent in patients with diabetes. Clinical judgment alone can lead to wrong diagnoses and delay the establishment of adequate therapies. Risk stratification according to individual factors is needed for selecting patients who might benefit from biopsy.

Diabetic nephropathy: Time to withhold development and progression - A review

The recent discoveries in the fields of pathogenesis and management of diabetic nephropathy have revolutionized the knowledge about this disease. Little was added to the management of diabetic nephropathy after the introduction of renin angiotensin system blockers. The ineffective role of the renin- angiotensin system blockers in primary prevention of diabetic nephropathy in type 1 diabetes mellitus necessitated the search for other early therapeutic interventions that target alternative pathogenic mechanisms. Among the different classes of oral hypoglycemic agents, recent studies highlighted the distinguished mechanisms of sodium glucose transporter 2 blockers and dipeptidyl peptidase-4 inhibitors that settle their renoprotective actions beyond the hypoglycemic effects. The introduction of antioxidant and anti-inflammatory agents to this field had also added wealth of knowledge. However, many of these agents are still waiting well-designed clinical studies in order to prove their beneficial therapeutic role. The aim of this review of literature is to highlight the recent advances in understanding the pathogenesis, diagnosis, the established and the potential renoprotective therapeutic agents that would prevent the development or the progression of diabetic nephropathy.

Clinical predictors differentiating non-diabetic renal diseases from diabetic nephropathy in a large population of type 2 diabetes patients

AIMS

Non-diabetic renal diseases (NDRDs) are associated with better renal outcomes than diabetic nephropathy (DN). This study was conducted to determine the common clinical markers predicting NDRDs in type 2 diabetes patients.

METHODS

Patients with type 2 diabetes mellitus who underwent a renal biopsy were screened. Eligible patients were categorized into two groups: DN group and NDRD group. Patient's clinical characteristics and laboratory data were collected. Logistic regression analysis was performed to identify risk factors for NDRD development, and the diagnostic performance of these variables was evaluated.

RESULTS

The study included 248 patients, 96 (38.71%) in the DN group and 152 (61.29%) in the NDRD group. Patients in the NDRD group had a shorter duration of DM and higher hemoglobin, estimated glomerular filtration rate, and urine osmotic pressure values as well as a higher incidence of glomerular hematuria than patients in the DN group. In the NDRD patients, the most common pathological type was membranous nephropathy (55, 36.18%). Absence of retinopathy (OR, 44.696, 95% CI, 15.91-125.566), glomerular hematuria (OR, 9.587, 95% CI, 2.027-45.333), and DM history ⩽5years (OR, 4.636, 95% CI, 1.721-12.486) were significant and independent risk factors for the development of NDRD (P<0.01). Absence of retinopathy achieved the overall highest diagnostic efficiency with a sensitivity of 92.11% and specificity of 82.29%. Glomerular hematuria had the highest specificity (93.75%).

CONCLUSION

Shorter duration of diabetes (⩽5years), absence of retinopathy, and presence of glomerular hematuria were independent indicators associated with NDRDs, indicating the need for renal biopsy.

Validation of a differential diagnostic model of diabetic nephropathy and non-diabetic renal diseases and the establishment of a new diagnostic model

BACKGROUND

The aims of the present study were to validate the differential diagnostic model of diabetic nephropathy (DN) and non-diabetic renal diseases (NDRD) established in 2003 and to establish a new diagnostic model suitable for the current clinical characteristics of DN.

METHODS

We examined 200 patients with Type 2 diabetes who underwent kidney biopsy from 2004 to 2012. The 2003 differential diagnostic model based on the data collected from 1993 to 2003 was evaluated by the diagnostic test and changes in the clinical differentiation parameters of DN and NDRD were analyzed. Logistic regression, receiver operating characteristics (ROC) curve, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analysis were applied.

RESULTS

The 2003 diagnostic model showed an accuracy of 77.5%. A significantly elevated incidence of hematuria, longer history of diabetes, and reduced level of glycated hemoglobin (HbA1c) were observed in the DN group from 2004 to 2012 compared with DN group from 1993 to 2003. Histories of diabetes mellitus (Dm), systolic blood pressure (Bp), HbA1c (Gh), hematuria (Hu), diabetic retinopathy (Dr), and hemoglobin (Hb) are independently related to DN. Thus, a new diagnostic model was constructed as follows: PDN  = exp (0.846 + 0.022 Dm + 0.033Bp + 2.050 Gh-2.664 Hu-0.078 Hb + 2.942Dr)/[1 + exp (0.846 + 0.022 Dm + 0.033 Bp + 2.050 Gh-2.664 Hu-0.078 Hb + 2.942 Dr)].Validation tests determined that the accuracy of the new model were 90.9%.

CONCLUSIONS

Changes in people with DN, clinical characteristics have reduced the diagnostic efficacy of the 2003 diagnostic model. The newly established model can provide a better, more current differentiation between DN and NDRD.

Identifying parameters to distinguish non-diabetic renal diseases from diabetic nephropathy in patients with type 2 diabetes mellitus: a meta-analysis

Background

Renal injuries in patients with diabetes include diabetic nephropathy (DN) and non-diabetic renal diseases (NDRD). The value of a clinical diagnosis of DN and NDRD remains inconclusive. We conducted a meta-analysis of the literature to identify predictive factors of NDRD and to compare the clinical characteristics of DN and NDRD for differential diagnosis.

Methods

We searched PubMed (1990 to January 2012), Embase (1990 to February 2009), and CNKI (1990 to January 2012) to identify studies that enrolled patients with DN and NDRD. Then, the quality of the studies was assessed, and data were extracted. The results were summarized as odds ratios (ORs) for dichotomous outcomes and weighted mean differences (WMDs) for continuous outcomes.

Results

Twenty-six relevant studies with 2,322 patients were included. The meta-analysis showed that the absence of diabetic retinopathy (DR) predicts NDRD (OR, 0.15; 95% confidence interval [CI], 0.09–0.26, p<0.00001). A shorter duration of diabetes mellitus (DM) also predicted NDRD (weighted mean difference, −34.67; 95% CI, −45.23–−24.11, p<0.00001). The levels of glycosylated hemoglobin (HbA1C%), blood pressure (BP), and total cholesterol were lower in patients with NDRD, whereas triglycerides and body mass index were higher. Other clinical parameters, including age, 24-h urinary protein excretion, serum creatinine, creatinine clearance, blood urea nitrogen, and glomerular filtration rate were not different between patients with NDRD and DN.

Conclusions

We identified that the absence of DR, shorter duration of DM, lower HbA1C, and lower BP may help to distinguish NDRD from DN in patients with diabetes. This could assist clinicians in making a safe and sound diagnosis and lead to more effective treatments.

Diabetic retinopathy in predicting diabetic nephropathy in patients with type 2 diabetes and renal disease: a meta-analysis

AIMS/HYPOTHESIS

The aim of this meta-analysis is to determine the predictive value of diabetic retinopathy in differentiating diabetic nephropathy from non-diabetic renal diseases in patients with type 2 diabetes and renal disease.

METHODS

Medline and Embase databases were searched from inception to February 2012. Renal biopsy studies of participants with type 2 diabetes were included if they contained data with measurements of diabetic retinopathy. Pooled sensitivity, specificity, positive predictive value, negative predictive value and other diagnostic indices were evaluated using a random-effects model.

RESULTS

The meta-analysis investigated 26 papers with 2012 patients. The pooled sensitivity and specificity of diabetic retinopathy to predict diabetic nephropathy were 0.65 (95% CI 0.62, 0.68) and 0.75 (95% CI 0.73, 0.78), respectively. The pooled positive and negative predictive value of diabetic retinopathy to predict diabetic nephropathy were 0.72 (95% CI 0.68, 0.75) and 0.69 (95% CI 0.67, 0.72), respectively. The area under the summary receiver operating characteristic curve was 0.75, and the diagnostic odds ratio was 5.67 (95% CI 3.45, 9.34). For proliferative diabetic retinopathy, the pooled sensitivity was 0.25 (95% CI 0.16, 0.35), while the specificity was 0.98 (95% CI 0.92, 1.00). There was heterogeneity among studies (p < 0.001), and no publishing bias was identified.

CONCLUSIONS/INTERPRETATION

Diabetic retinopathy is useful in diagnosing or screening for diabetic nephropathy in patients with type 2 diabetes and renal disease. Proliferative diabetic retinopathy may be a highly specific indicator for diabetic nephropathy.

Prevalence of diabetic nephropathy complicating non-diabetic renal disease among Chinese patients with type 2 diabetes mellitus

Background

The incidence of diabetes mellitus (DM) and diabetic nephropathy (DN) have risen rapidly in the past few decades and have become an economic burden to the healthcare system in China. DN is a major complication of DM and is a leading cause of end-stage renal disease (ESRD). The occurrence of non-diabetic renal disease (NDRD) in diabetic patients has been increasingly recognized in recent years. It is generally believed that it is difficult to reverse DN, whereas some cases of NDRD are readily treatable and remittable. However, DN is known to co-exist with NDRD in a poorly defined population of patients with type 2 diabetes mellitus (T2DM). This study estimated the prevalence of co-existing DN and NDRD in Chinese patients.

Methods

Data were retrospectively analyzed from 244 patients with T2DM who had undergone a renal biopsy between January 2003 and December 2011 at the Nephrology Department, China-Japan Friendship Hospital, China. Male patients numbered 151 (61.9%) of the study population. The biopsies were performed because urinary abnormalities or renal function were atypical of a diagnosis of DN. Biopsy samples were examined using light, immunofluorescence (IF) and electron microscopy (EM). Clinical parameters were recorded for each patient at the time of biopsy.

Results

Nineteen of 244 diabetic patients (7.8%) had co-existing DN and NDRD. These patients showed clinical features and pathologic characteristics of DN, including a high prevalence of diabetic retinopathy (89.5%), a long duration of diabetes, increased thickness of the glomerular basement membrane (GBM) and mesangial expansion. However, they also presented with clinical findings which were inconsistent with DN, such as hematuria, rapidly progressive renal failure and marked proteinuria. Immunoglobulin A (IgA) nephropathy was apparent in 10 out of the 19 patients (52.6%), tubulointerstitial lesions were found in four patients (21.1%), membrano-proliferative glomerulonephritis (MPGN) in three patients (15.8%) and membranous nephropathy (MN) in two patients (10.5%).

Conclusion

Retrospective analysis of biopsy data suggests that approximately 8% of Chinese patients with T2DM may have co-existing DN and NDRD. The most common histological diagnosis in our small series was IgA nephropathy.

Evaluation of renal biopsies in type 2 diabetic patients with kidney disease: a clinicopathological study of 216 cases

OBJECTIVES

The outcome and the therapy of patients with diabetes mellitus (DM), diabetic nephropathy (DN), and non-diabetic renal disease (NDRD) are quite different, so the differential diagnosis is of considerable importance. To evaluate the usefulness of renal biopsy in type 2 diabetic patients, we examined the relationship between the clinical parameters and the histopathological findings in different age groups.

METHODS

Renal biopsy specimens and clinical and laboratory data from 216 patients with type 2 DM were evaluated. According to their age, three groups were defined: 17-35 years (group I), 36-59 years (group II), and more than 60 years (group III).

RESULTS

The study showed that, beside the duration of diabetes, other clinical parameters were not significantly different between the three groups. Chronic nephritic syndrome was the most common clinical manifestation in group I (44.1 %) and in group II (34.0 %). Among patients in group III, we found a high prevalence of chronic renal failure (34.3 %) and nephrotic syndrome (28.6 %). Consistent with the clinical manifestations, IgA nephropathy was the most common pathologic finding in group I (29.4 %) and in group II (34.7 %), whereas the most frequent abnormalities in group III were membranous nephropathy (25.7 %) and tubulointerstitial lesions (14.3 %). Overall, among these patients, 14 cases were diagnosed with DN (6.5 %), 179 with NDRD (82.9 %), while 23 had concurrent DN and NDRD (10.7 %).

CONCLUSIONS

Our results indicated that the clinical manifestations and pathologic findings in type 2 diabetic patients in different age groups have different features. This study emphasized the usefulness of renal biopsy for determining the pattern of renal damage and thus for the overall management of type 2 diabetic patients.

Nondiabetic renal disease in type 2 diabetic patients: a review of our experience in 220 cases

BACKGROUND

The purpose of this retrospective study was to evaluate the renal biopsies performed on type 2 diabetic patients for suspicion of nondiabetic renal disease (NDRD) and to correlate the pathological finding with the clinical and laboratory findings.

METHODS

From January 1999 to December 2009, 220 people with type 2 diabetes for clinically suspected NDRD underwent renal biopsy. The case records of these patients were retrospectively analyzed. Based on the biopsy findings, patients were divided into two groups: Group I, isolated diabetic glomerulosclerosis (DGS), and Group II, NDRD with underlying DGS. Clinical and laboratory data were analyzed in relation to the histopathological findings.

RESULTS

Of the 220 patients studied, 153 were males and 67 were females. The average age was 51.35 years (30-79). Renal biopsy showed that 100 patients (45.5%) had NDRD with underlying DGS. Group II had a significantly higher level of proteinuria and hematuria but less frequent diabetic retinopathy. There was no significant difference between the two groups in age, duration of diabetes, presence of hypertension, serum creatinine, and glomerular filtration rate. IgA nephropathy was the most common, accounting for 34% of Group II, membranous nephropathy ranked second accounting for 22.0%, followed by mesangial proliferative nephritis for 14%.

CONCLUSION

This study showed that IgA nephropathy is the commonest NDRD among diabetics. The absence of retinopathy, especially when associated with nephritic proteinuria and hematuria, strongly predicts NDRD superimposed on DGS. Renal biopsy should be performed in diabetics when the clinical scenario is atypical.

Coincident idiopathic focal segmental glomerulosclerosis collapsing variant and diabetic nephropathy in an African American homozygous for MYH9 risk variants

Familial clustering of disparate kidney diseases including clinically diagnosed hypertensive and diabetic nephropathy, idiopathic focal segmental glomerulosclerosis, and HIV-associated nephropathy are often observed in African Americans. Admixture mapping recently identified the nonmuscle myosin heavy chain 9 gene (MYH9) as a susceptibility factor strongly associated with several nondiabetic etiologies of end-stage renal disease in African Americans, less strongly with diabetes-associated end-stage renal disease. MYH9-associated nephropathies reside in the spectrum of focal segmental glomerulosclerosis/focal global glomerulosclerosis. The renal histology in proteinuric African Americans homozygous for MYH9 risk variants with longstanding type 2 diabetes mellitus is unknown. We report a case of coincident idiopathic focal segmental glomerulosclerosis collapsing variant and diabetic nephropathy in an African American homozygous for the MYH9 E1 risk haplotype. This case demonstrates that diabetic African Americans with overt proteinuria can have mixed renal lesions, including those in the spectrum of MYH9-associated nephropathy. Careful interpretation of kidney biopsies in proteinuric African Americans with diabetes is necessary to exclude coincident nondiabetic forms of nephropathy, precisely define etiologies of kidney disease, and determine the natural history and treatment response in mixed lesions of diabetes-associated and MYH9-associated kidney disease.

Clinical indicators which necessitate renal biopsy in type 2 diabetes mellitus patients with renal disease

BACKGROUND

The diagnosis of diabetic nephropathy (DN) is always based on clinical grounds. However, the necessity for renal biopsy of type 2 diabetes mellitus (DM) patients with renal disease to establish the diagnosis remains unclear.

METHODS

We retrospectively studied 50 type 2 diabetic patients performed with renal biopsy between December 2002 and December 2006. Based on renal pathology, patients were divided into group I: DN alone, group II: non-diabetic renal disease (NDRD) superimposed on DN and group III: isolated NDRD. Factors like DM > 10 years, retinopathy, previous minimal proteinuria without sudden heavy proteinuria, no glomerular haematuria and non-small-sized kidney were collected to evaluate their sensitivity, specificity, positive predictive value and negative predictive value for prediction of DN or NDRD in type 2 diabetic patients.

RESULTS

Group I consisted of 24 patients, group II 15 patients and group III 11 patients. Acute interstitial nephritis was the most prevalent second renal disease in our study. Sensitivity and specificity for group I was poor in five features except high sensitivity in no sudden heavy proteinuria (83.3%) and non-small-sized kidney (95.8%). Comparable retinopathy, sudden heavy proteinuria and haematuria (p > 0.05) was noted between the three groups. Significant biopsy indicators included higher serum albumin, lower urinary daily protein excretion and lower 24-h creatinine clearance (C(Cr)) rate (p < 0.05).

CONCLUSION

Our study demonstrated that DM > 10 years and retinopathy did not exclude NDRD in type 2 DM patients, and need for renal biopsy. Higher serum albumin, lower urinary daily protein and 24-h C(Cr) were indicative for biopsy to exclude NDRD.

Rapidly progressive renal failure in type 2 diabetes in the tropical environment: a clinico-pathological study

BACKGROUND

Rapid decline of renal function in a diabetic suggests the presence of a nondiabetic kidney disease (NDKD). We designed a prospective study to evaluate the factors associated with a rapid decline in renal function in patients with type 2 diabetes.

METHODS

Over a 2 and a half year period, all patients with type 2 diabetes who presented with documented doubling of serum creatinine in less than 4 weeks or recently diagnosed advanced renal failure were identified. Patients with prerenal causes, urinary tract obstruction, or systemic disease causing renal failure were not included. Renal histology was studied in all cases.

RESULTS

A total of 26 patients satisfied the inclusion criteria. Over 75% had serum creatinine >4 mg/dL at presentation and 62% were dialysis dependent. Renal histology showed mixed lesions of diabetic nephropathy (DN) and NDKD in 11 cases, only DN in nine, and pure NDKD in six. Diffuse proliferative glomerulonephritis (DPGN) was the commonest NDKD (27% cases), all on a background of DN. History of preceding cutaneous or pharyngeal infection was available in five cases. The proportion of postinfectious glomerulonephritis in diabetics with rapidly progressive renal failure was over six times that of the nondiabetic adult RPRF population during the study period. Four patients had acute interstitial nephritis and three showed crescentic glomerulonephritis. Other lesions included amyloidosis, atheroembolic disease, and renal papillary necrosis (one each). The frequency of microscopic hematuria and retinopathy was similar in those with pure DN and NDKD. Four out of seven cases with DPGN showed partial recovery whereas the other three remained unchanged.

CONCLUSIONS

About two-thirds of patients with type 2 diabetes presenting with rapid decline of renal function in a tropical environment show NDKD. The high incidence of postinfectious glomerulonephritis in this group is possibly related to the high prevalence of skin and soft tissue infections; and could contribute to progressive kidney disease.