Prevalence of non-diabetic renal disease in patients with type 2 diabetes

Refining Non-Invasive Diagnosis of Diabetic Nephropathy: The Role of Renal Artery Resistive Index

RATIONALE AND OBJECTIVES

Accurate differentiation between diabetic nephropathy (DN) and non-diabetic renal disease (NDRD) in type 2 diabetes mellitus (T2DM) patients is crucial for effective management. This study aims to evaluate the diagnostic value of ultrasound, particularly the renal artery resistive index (RRI), in distinguishing DN from NDRD in T2DM patients with early to mid-stage chronic kidney disease (CKD).

MATERIALS AND METHODS

This retrospective study included 164 T2DM patients with renal disease who underwent renal biopsy. Patients were divided into a derivation group (137) and a validation group (27). Each group was further categorized into DN and NDRD subgroups based on biopsy results. Clinical, laboratory, and ultrasound data, including RRI and diabetic retinopathy (DR), were analyzed to differentiate DN from NDRD.

RESULTS

RRI values were significantly higher in DN patients, with optimal cutoffs of ≥ 0.72 for CKD stages 1-2 and ≥ 0.74 for stage 3. Combining RRI with DR achieved a specificity and positive predictive value (PPV) of 100% for diagnosing DN, confirmed in the validation group.

CONCLUSIONS

This study emphasizes the need for distinct RRI cutoff values for T2DM patients in early and mid-stage CKD. Stage-specific RRI cutoffs, combined with DR, provide a reliable, non-invasive approach to distinguish DN from NDRD, enhancing clinical decision-making.

Non-Diabetic Renal Diseases in Diabetic Patients with Emphasis on Infection-Related Glomerulonephritis

Background:

Non -diabetic renal diseases (NDRDs) in diabetics are treatable and therefore have better prognosis. Infection-related glomerulonephritis (IRGN) is being frequently reported as NDRD.

Objective:

We attempt to study the clinicopathologic spectrum of diabetic patients with biopsy proven IRGN.

Materials and Methods:

This was a retrospective analysis of renal biopsies performed in diabetic patients from January 2014 to June 2021. Demographic data, clinical features, and other laboratory findings were collected. The renal biopsies were classified into diabetic nephropathy (DN) and NDRD. The patients with diagnosis of IRGN were studied in detail.

Results:

Of the 1972 renal biopsies done in diabetic patients, 537 were NDRD and 1233 were DN. The commonest NDRD was tubulo-interstitial nephritis (n = 173) followed by IRGN (n = 74). The IRGN cases were in the age range of 5-78 years (median-53.5) with M: F = 3.4:1. The median duration of diabetes was six years, with median HbA1c = 7.5. Proteinuria ranged from 0.041 to 13 g/day (median = 1.95) with median serum creatinine of 3.7 mg%. History of preceding infection was present in nine cases. These patients presented with rapidly progressive renal failure (RPRF, 17), nephritic syndrome (27), nephrotic syndrome (27), and asymptomatic proteinuria (3). Median C3-level was 47 mg/dl. The biopsies showed classic endocapillary hypercellularity with neutrophils in mesangium, 45 cases had associated DN. Immunofluorescence performed in 54 cases showed coarse granular deposits of C3C.

Conclusions:

IRGN should be kept in mind in diabetic patients presenting with RPRF or nephrotic proteinuria. The biopsy and immunofluorescence helps in accurate diagnosis.

Clinico-pathological features of diabetic and non-diabetic renal diseases in type 2 diabetic patients: a retrospective study from a 10-year experience in a single center

AIM

To compare clinical and pathological characteristics as well as prognosis between diabetic nephropathy (DN) and non-diabetic renal disease (NDRD) so as to explore potential diagnostic criteria of DN and provide some guidance for the treatment of type 2 diabetes mellitus (T2DM) patients with kidney involvement.

METHODS

T2DM patients with renal impairment who underwent kidney biopsy were included in this study, who were classified into 3 groups (DN, NDRD, DN with NDRD) based on their renal pathological diagnosis. Baseline clinical characteristics as well as follow-up data were collected and analyzed among 3 groups. Logistic regression was performed to determine the best predictors for DN diagnosis. Additional 34 MN patients without diabetes were enrolled by propensity score matching method to compare serum PLA2R antibody titer and kidney outcomes between diabetic MN patients and MN alone.

RESULTS

Among 365 patients with type 2 diabetes who underwent kidney biopsy, 179 (49.0%) patients were diagnosed with NDRD alone and 37 (10.1%) patients with NDRD combined DN. Risk factors for DN development in T2DM patients were longer time since diabetes diagnosis, higher level of serum creatinine, absence of hematuria and presence of diabetic retinopathy by multivariate analysis. Lower rate of proteinuria remission and higher risk of renal progression were observed in DN group compared with NDRD group. Membranous nephropathy was the most common NDRD in diabetic patients. There was no difference in serum PLA2R antibody positiveness or titer between MN patients with or without T2DM. There was lower remission rate but similar renal progression in diabetic MN when age, gender, baseline eGFR, albuminuria and IFTA score were adjusted.

CONCLUSIONS

Non-diabetic renal disease is not uncommon in T2DM patients with renal impairment, which has better prognosis with proper treatment. Coexisting diabetic status does not exert negative impact on renal progression in MN patients, and immunosuppressive agents should be administered when necessary.

CureGN-Diabetes Study: Rationale, Design, and Methods of a Prospective Observational Study of Glomerular Disease Patients with Diabetes

Glomerular diseases (GDs) represent the third leading cause of end-stage kidney disease (ESKD) in the US Diabetes was excluded from the CureGN Study, an NIH/NIDDK-sponsored observational cohort study of four leading primary GDs: IgA nephropathy (IgAN), membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS), and minimal change disease (MCD). CureGN-Diabetes, an ancillary study to CureGN, seeks to understand how diabetes influences the diagnosis, treatment, and outcomes of GD. It is a multicenter, prospective cohort study, targeting an enrollment of 300 adults with prevalent type 1 or type 2 diabetes and MCD, FSGS, MN, or IgAN, with first kidney biopsy obtained within 5 years of enrollment in 80% (20% allowed if biopsy after 2010). CureGN and Transformative Research in DiabEtic NephropaThy (TRIDENT) provide comparator cohorts. Retrospective and prospective clinical data and patient-reported outcomes are obtained. Blood and urine specimens are collected at study visits annually. Kidney biopsy reports and digital images are obtained, and standardized pathologic evaluations performed. Light microscopy images are uploaded to the NIH pathology repository. Outcomes include relapse and remission rates, changes in proteinuria and estimated glomerular filtration rate, infections, cardiovascular events, malignancy, ESKD, and death. Multiple analytical approaches will be used leveraging the baseline and longitudinal data to compare disease presentation and progression across subgroups of interest. With 300 patients and an average of 3 years of follow-up, the study has 80% power to detect a HR of 1.4-1.8 for time to complete remission of proteinuria, a rate ratio for hospitalizations of 1.18-1.56 and difference in eGFR slope of 6.0-8.6 mL/min/year between two groups of 300 participants each. CureGN-Diabetes will enhance our understanding of diabetes as a modifying factor of the pathology and outcomes of GDs and support studies to identify disease mechanisms and improve patient outcomes in this understudied patient population.

Histopathologic and clinical features of diabetic nephropathy alone and with concomitant nondiabetic renal diseases

Background and objective: Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM) and one of the leading causes of end-stage kidney disease. The aim of the present study was to evaluate the histomorphological and clinical profiles of DN and associated non-diabetic renal dieases (NDRD) in diabetic patients. Materials and methods: The study was carried out at the Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Dhaka, from July 2019 to December 2020. Renal biopsy samples from known diabetic patients were included in the study. The formalin-fixed tissues were stained with haematoxylene & eosin (H&E), Periodic acid Schiff (PAS), Masson Trichrome (MT) and Jones Methanamine Silver (JMS) stains. Tissues were stained for IgG, IgA, IgM, C3, C1q, kappa and lambda for direct immunofluorescence (DIF) study. DN was histologically classified according to Tervaert classification system. Interstitial fibrosis and tubular atrophy (IFTA) as well as arteriolar hyalinization scoring was also done. Clinical information was retrieved from the patient’s information sheet. Results: Total 46 biopsy samples from DN cases were included in the study. The mean age of the cases was 46.76+10.63 years, including 36 males and 10 females. The most common clinical presentation was nephritic range proteinuria (n=32, 69.56%). Among all, 27 (58.69%) patients had haematuria. The mean serum creatinine level was 4.28+2.61 mg/dl, and 80.43% had serum creatinine levels >1.5 mg/dl. Histopathologic examinatiom revealed type III DN in 26 (56.5%) and type IV DN in 11 (23.9%) cases. IFTA score 1 (<25%) was seen in 20 (43.5%), score 2 (25-50%) in 19 (41.3%) and score 3 (>50%) in 7 (15.2%). Vascular hyalinization score-2 in 25 (54.3%), score-1 in 14 (30.4%) and score-0 in 7 (15.2%). DN class II, III and IV were associated with high urinary total protein (UTP) and serum creatinine levels. Among the histologic changes, percentage of glomerular sclerosis, the mean IFTA score and vascular hyalinization score were found to be highest in class IV DN, and all were significantly associated with histologic glomerular DN classes (p= <0.05). Of the total cases, 21 (45.65%) were found with nondiabetic renal diseases (NDRD), the most common feature was focal segmental glomerulosclerosis (FSGS) (26.57%), followed by IgA nephropathy and post-infectious glomerulonephritis (PIGN). Among 46 cases, one post-transplant biopsy was included, which revealed class II DN along with features of calcineurin inhibitor toxicity. Conclusion: Tervaert’s histologic classification of our cases revealed class III DN lesions as the predominant one, and the classes had a significant association with age of the patient, serum creatinine level, mean IFTA, arteriolar hyalinization and NDRD. Among the NDRD, FSGS was the most common pathology. IMC J Med Sci. 2023; 17(1): 003. DOI: https://doi.org/10.55010/imcjms.17.003 *Correspondence: Sk Md Jaynul Islam, Department of Histopathology, Armed Forces Institute of Pathology, Dhaka Cantonment, Dhaka, Bangladesh. Email: jaynul.islam@gmail.com

Rare Case of C3 Glomerulopathy in a Patient of Type 1 Diabetes Mellitus

Complement component 3 glomerulopathy (C3G) is a recently defined entity comprising dense deposit disease and C3 glomerulonephritis. It is associated with nonrenal diseases such as diabetes mellitus (DM) type 1, ocular drusen, acquired partial lipodystrophy, and monoclonal gammopathy of undetermined significance. We describe a case of 13-year-old boy of the known case of type 1 DM, who developed proteinuria, and swelling over his face, and lower limbs, which on renal biopsy, was diagnosed as a case of C3G.

Establishment and Validation of a Nomogram Model for Prediction of Diabetic Nephropathy in Type 2 Diabetic Patients with Proteinuria

PURPOSE

To establish and validate the nomogram model for predicting diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) patients with proteinuria.

METHODS

A total of 102 patients with T2DM and proteinuria who underwent renal biopsy were included in this study. According to pathological classification of the kidney, the patients were divided into two groups, namely, a DN group (52 cases) and a non-diabetic renal disease (NDRD) group (50 cases). The clinical data were collected, and the factors associated with diabetic nephropathy (DN) were analyzed with multivariate logistic regression. A nomogram model for predicting DN risk was constructed by using R4.1 software. Receiver operator characteristic (ROC) curves were generated, and the K-fold cross-validation method was used for validation. A consistency test was performed by generating the correction curve.

RESULTS

Systolic blood pressure (SBP), diabetic retinopathy (DR), hemoglobin (Hb), fasting plasma glucose (FPG) and triglyceride/cystatin C (TG/Cys-C) ratio were independent factors for DN in T2DM patients with proteinuria (P<0.05). The nomogram model had good prediction efficiency. If the total score of the nomogram exceeds 200, the probability of DN is as high as 95%. The area under the ROC curve was 0.9412 (95% confidence interval (CI) = 0.8981-0.9842). The 10-fold cross-validation showed that the prediction accuracy of the model was 0.8427. The Hosmer-Lemeshow (H-L) test showed that there was no significant difference between the predicted value and the actual observed value (X ² = 6.725, P = 0.567). The calibration curve showed that the fitting degree of the DN nomogram prediction model was good.

CONCLUSION

The nomogram model constructed in the present study improves the diagnostic efficiency of DN in T2DM patients with proteinuria, and it has a high clinical value.

Characterizing predictors of non-diabetic kidney disease (NDKD) in diabetic patients

BACKGROUND

Diabetic kidney disease (DKD) is the chief cause of renal involvement in diabetic patients. It is primarily a clinical diagnosis. Non-diabetic kidney disease (NDKD) may be missed if they are not biopsied. In this study, we describe the spectrum of NDKD and evaluate the predictors considered for planning a biopsy in diabetic patients with kidney disease.

METHODS

In a retrospective cohort study, diabetic patients who underwent kidney biopsy at our centre between May 2006 and July 2019 were evaluated for NDKD.

RESULTS

321 diabetic patients who underwent kidney biopsy were analyzed. Mean age was 49.3 ± 12.4 years and 71% were males. 75.8% patients had hypertension and 25.2% had diabetic retinopathy. Based on the kidney biopsy, patients were classified as DKD-127 (39.6%), NDKD-179(55.8%) and combined DKD + NDKD-15(4.7%). Overall, the most commonly diagnosed pathology was membranous nephropathy-MN (17%), followed by IgA nephropathy (16.0%) and focal segmental glomerulosclerosis-FSGS (14.9%). In patients with DKD + NDKD, IgA nephropathy (53.3%) was predominant. 165 (51.4%) patients had a diagnosis potentially amenable to a specific therapy. On multivariate analysis, female gender [OR 2.07 (1.08-3.97), p = 0.02], absence of diabetic retinopathy [OR 7.47 (3.71-15), p < 0.001] absence of hypertension [OR 3.17 (1.56-6.45), p = 0.001] and duration of diabetes ≤ 24 months [OR 3.67(1.97-6.84), p < 0.001], were independent predictors for NDKD while the absence of nephrotic range proteinuria [OR 1.73 (0.98-3.05), p 0.05] showed a trend towards significance.

CONCLUSION

Astute use of kidney biopsy can detect potentially treatable NDKD in a large number of diabetic patients with glomerular diseases being the predominant diagnosis. A combination of risk factors needs to be considered to guide the need for kidney biopsy in diabetic patients.

Kidney Biopsy in Type 2 Diabetic Patients: Critical Reflections on Present Indications and Diagnostic Alternatives

Roughly 3% of patients worldwide with a new diagnosis of type 2 diabetes mellitus (T2DM) already have an overt nephropathy at diagnosis and about 20-30% of the remaining ones develop a complication of this kind later in life. The early identification of kidney disease in diabetic patients is important as it slows its progression, which is important not only because this reduces the need for renal replacement therapy, but also because it decreases the high rate of mortality and morbidity associated with a reduction in kidney function. The increasing prevalence of type 2 diabetes and the consequent greater probability of finding different types of kidney diseases in diabetic patients frequently gives rise to overlapping diagnoses, a definition encompassing the differential diagnosis between diabetic and non-diabetic kidney disease. The issue is made more complex by the acknowledgement of the increasing frequency of presentations of what is termed "diabetic kidney disease" without relevant proteinuria, in particular in T2DM patients. Distinguishing between diabetes related and non-diabetes related forms of kidney disease in diabetic patients is not only a semantic question, as different diseases require different clinical management. However, while the urologic and macrovascular complications of diabetes, as well as overlapping parenchymal damage, can be diagnosed by means of imaging studies, often only a kidney biopsy will make a differential diagnosis possible. In fact, the coexistence of typical diabetic lesions, such as nodular glomerulopathy or glomerulosclerosis, with different glomerular, vascular and tubulo-interstitial alterations has been extensively described, and an analysis of the dominant histological pattern can contribute to determining what therapeutic approach should be adopted. However, due to the high frequency of kidney diseases, and to the fact that T2DM patients are often affected by multiple comorbidities, a kidney biopsy is not generally performed in T2DM patients. What follows is a review aiming to discuss the diagnostic work-up, on the base of clinical, laboratory and imaging criteria, and evaluate the present indications and alternatives to renal biopsy.

Differences between diabetic and non-diabetic nephropathy patients in cardiac structure and function at the beginning of hemodialysis and their impact on the prediction of mortality

OBJECTIVES

To characterize differences in cardiac structure and function in hemodialysis (HD) patients with diabetic nephropathy (DN) and in those without using echocardiography and to determine their impact on the prediction of mortality using echocardiographic parameters.

METHODS

Clinical, laboratory, and echocardiographic data were collected from patients commencing HD.

RESULTS

Compared with those without DN, patients with DN had lower peak velocity of the early diastolic wave (e'), larger left atria, and higher peak early diastolic velocity (E)/e' and peak velocity of tricuspid regurgitation (TR). In addition, a larger proportion of DN patients had a combination of left ventricular (LV) diastolic dysfunction, cardiac valve calcification, moderate-to-severe cardiac valve regurgitation (CVR), and at least moderate pericardial effusion (PE). After accounting for age, sex, smoking, hypertension, hemoglobin, and albumin, DN was responsible for e'  < 10 cm/s, E/e' >13 m/s, TR >2.8 m/s, LV diastolic dysfunction, CVR, and PE. LV diastolic dysfunction and E/e' >13 were the most useful predictors of mortality in patients with DN.

CONCLUSIONS

Patients with DN who undergo HD tend to have worse LV diastolic function and are more likely to have heart valve problems. LV diastolic dysfunction and E/e' are predictors of death in DN patients.

Primary glomerulonephritis in diabetic patients

BACKGROUND

Primary glomerulonephritis (PGN) has a significant part in non-diabetic kidney disease (NDKD) in diabetes mellitus (DM) patients. In our study, we compared the clinical, demographic and laboratory features of patients with biopsy-proven diabetic nephropathy (DN) and PGN with type 2 DM.

METHODS

In our retrospective study, type 2 DM patients who underwent kidney biopsy between 2011 and 2019 were included. Demographic, clinical and laboratory characteristics of DN and PGN patients were compared.

RESULTS

Seventy patients with a mean age of 55.7 ± 9.4 and 43 (61.4%) males were included. About 38 (54.3%) of the patients had DN and 32 (45.7%) had PGN. In the PGN, membranous GN (20, 62.5%) was most common. In DN patients, diabetes duration was longer; complications such as retinopathy, neuropathy, hypertension, coronary artery disease, heart failure were more frequent. At the time of renal biopsy, blood sugar, HbA1C, blood pressure, serum albumin and proteinuria values were similar in two groups. The pathological damage findings of kidney biopsy in DN patients were more severe. In the first year after kidney biopsy decrease in eGFR was higher in DN patients, whereas eGFR did not change in PGN patients.

CONCLUSION

In a diabetic patient, fasting blood sugar, hbA1C, serum albumin and proteinuria did not differ in the differential diagnosis of DN and PGN, whereas complications of DM (retinopathy, neuropathy, hypertension, coronary artery disease) were more characteristic in differentiation. Detection of PGN in a diabetic patient is crucial for the success of the treatment, according to DN.

Potential Role of the Renal Arterial Resistance Index in the Differential Diagnosis of Diabetic Kidney Disease

AIMS

To investigate the potential role of renal arterial resistance index (RI) in the differential diagnosis between diabetic kidney disease (DKD) and non-diabetic kidney disease (NDKD) and establish a better-quantified differential diagnostic model.

MATERIALS AND METHODS

We consecutively reviewed 469 type 2 diabetes patients who underwent renal biopsy in our center. According to the renal biopsy results, eligible patients were classified into the DKD group and the NDKD group. The diagnostic significance of RI was evaluated by receiver operating characteristic (ROC) curve analysis. Logistic regression analysis was used to search for independent risk factors associated with DKD. Then a novel diagnostic model was established using multivariate logistic regression analysis.

RESULTS

A total of 332 DKD and 137 NDKD patients were enrolled for analysis. RI was significantly higher in the DKD group compared with those in the NDKD group (0.70 vs. 0.63, p< 0.001). The optimum cutoff value of RI for predicting DKD was 0.66 with sensitivity (69.2%) and specificity (80.9%). Diabetic retinopathy, diabetes duration ≥ 60 months, HbA1c ≥ 7.0(%), RI ≥ 0.66, and body mass index showed statistical significance in the multivariate logistic regression analysis. Then, we constructed a new diagnostic model based on these results. And the validation tests indicated that the new model had good sensitivity (81.5%) and specificity (78.6%).

CONCLUSIONS

RI has a potential role in discriminating DKD from NDKD. The RI-based predicting model can be helpful for differential diagnosis of DKD and NDKD.

A retrospective cohort study on the pathology and outcomes of type 2 diabetic patients with renal involvement

OBJECTIVE

To investigate the association of clinical and histological characteristics and the development of ESRD in T2DM patients with renal involvement.

METHODS

We conducted a retrospective analysis of clinical and pathologic data from T2DM patients who underwent renal biopsy (n = 120).

RESULTS

The mean age, duration of diabetes, and eGFR were 50.9 ± 11.2 years, 92.8 ± 41.3 months, 55.1 ± 42.3 mL/min/1.73 m², respectively. Among these patients, 57 (47.5%) were diagnosed with diabetic nephropathy (DN), and 63 (52.5%) with non-diabetic renal disease (NDRD). The most common subtype of NDRD is membranous nephropathy. Compared with the NDRD group, the DN group had a longer duration of diabetes, worse renal function, and a higher proportion of diabetic retinopathy. Kaplan-Meier analysis showed that the 5-year renal survival rate of the DN group was only 41%, whereas that of the NDRD group was 84%. ESRD was defined as eGFR below 15 mL/min/1.73 m². After multivariate adjustment, the risk of ESRD in DN patients was 3.81 times higher than that in NDRD patients. According to Glomerular Class, the 5-year renal survival rate of type IIA, IIB, III, and IV in the DN group was 88, 56, 28, and 15%, respectively. Kaplan-Meier analysis showed that there was a significant difference in renal survival among different glomerular classes or different interstitial fibrosis and tubular atrophy (IFTA) scores. But Cox proportional hazards analysis indicated that only IFTA score (HR 2.75, 95% CI 1.37-5.51, P = 0.001), but not the glomerular class (HR 1.21, 95% CI 0.73-2.00, P = 0.465), could predict renal outcome when adjusting for multivariate.

CONCLUSION

The prognosis of DN patients is significantly worse than that of NDRD patients. Compared with glomerular lesions, tubulointerstitial lesions were associated with higher risk for renal death in DN patients.

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.

Risk factors for non-diabetic renal disease in diabetic patients

BACKGROUND

Diabetic patients with kidney disease have a high prevalence of non-diabetic renal disease (NDRD). Renal and patient survival regarding the diagnosis of diabetic nephropathy (DN) or NDRD have not been widely studied. The aim of our study is to evaluate the prevalence of NDRD in patients with diabetes and to determine the capacity of clinical and analytical data in the prediction of NDRD. In addition, we will study renal and patient prognosis according to the renal biopsy findings in patients with diabetes.

METHODS

Retrospective multicentre observational study of renal biopsies performed in patients with diabetes from 2002 to 2014.

RESULTS

In total, 832 patients were included: 621 men (74.6%), mean age of 61.7 ± 12.8 years, creatinine was 2.8 ± 2.2 mg/dL and proteinuria 2.7 (interquartile range: 1.2-5.4) g/24 h. About 39.5% (n = 329) of patients had DN, 49.6% (n = 413) NDRD and 10.8% (n = 90) mixed forms. The most frequent NDRD was nephroangiosclerosis (NAS) (n = 87, 9.3%). In the multivariate logistic regression analysis, older age [odds ratio (OR) = 1.03, 95% CI: 1.02-1.05, P < 0.001], microhaematuria (OR = 1.51, 95% CI: 1.03-2.21, P = 0.033) and absence of diabetic retinopathy (DR) (OR = 0.28, 95% CI: 0.19-0.42, P < 0.001) were independently associated with NDRD. Kaplan-Meier analysis showed that patients with DN or mixed forms presented worse renal prognosis than NDRD (P < 0.001) and higher mortality (P = 0.029). In multivariate Cox analyses, older age (P < 0.001), higher serum creatinine (P < 0.001), higher proteinuria (P < 0.001), DR (P = 0.007) and DN (P < 0.001) were independent risk factors for renal replacement therapy. In addition, older age (P < 0.001), peripheral vascular disease (P = 0.002), higher creatinine (P = 0.01) and DN (P = 0.015) were independent risk factors for mortality.

CONCLUSIONS

The most frequent cause of NDRD is NAS. Elderly patients with microhaematuria and the absence of DR are the ones at risk for NDRD. Patients with DN presented worse renal prognosis and higher mortality than those with NDRD. These results suggest that in some patients with diabetes, kidney biopsy may be useful for an accurate renal diagnosis and subsequently treatment and prognosis.

Predictors and histopathological characteristics of non-diabetic renal disorders in diabetes: a look from the tubulointerstitial point of view

BACKGROUND

Prevalence and characteristics of non-diabetic renal diseases (NDRD) in patients with type 2 diabetes mellitus is different between populations, and seems to be largely dependent on biopsy policies.

AIM

To investigate clinical clues for NDRD in patients with type 2 diabetes mellitus and to analyse renal prognosis of patients based on pathological diagnosis.

METHODS

We retrospectively searched medical records of 115 patients with type 2 diabetes who underwent a renal biopsy between 2004 and 2018. Patients were divided into three groups as diabetic nephropathy (DN), NDRD + DN or NDRD based on histopathological examination.

RESULTS

Thirty-six (31.3%) patients had DN, 33 (28.7%) had DN + NDRD and 46 (40%) had NDRD. The absence of diabetic retinopathy, recent onset of diabetes, abnormal disease chronology, and blood haemoglobin was associated with the presence of NDRD in univariate analysis. Abnormal disease chronology which was defined as the presence of acute proteinuria and/or acute kidney injury that are unexpected to be related to evolution of diabetic nepropathy (odds ratio 4.65, 95% confidence interval 1.44-15.00; P = 0.010) and absence of diabetic retinopathy (odds ratio 3.44, 95% confidence interval 1.32-8.98; P = 0.012) were independently associated with the presence of NDRD in multivariate analysis. Focal segmental glomerulosclerosis was the most frequent type of NDRD. Diseases that affect tubulointerstitial area were more prevalent in the DN + NDRD group compared to the NDRD group (P = 0.001). Renal survival, which was defined as evolution to end-stage renal disease, was 59.5 ± 14.4 months, 93.7 ± 11.7 months and 87.2 ± 2.6 months for DN, DN + NDRD and NDRD groups, respectively (P = 0.005).

CONCLUSIONS

Renal biopsy is essential in certain clinical conditions as diagnosis of NDRD is vital for favourable renal survival. DN may facilitate superimposed tubular injury in the presence of toxic insults.

The Value of Renal Biopsy in Non-Insulin-Dependent Diabetes Mellitus in Singapore over the Past Two Decades

Objective

This study on the prevalence of diabetic nephropathy (DN) and coexistence of non-diabetic renal disease (NDRD) in a cohort of 255 non-insulin-dependent diabetes mellitus (NIDDM) patients aims to determine the value of performing renal biopsies in these patients and elucidate the factors which could affect their progression to end-stage renal disease (ESRD).

Methods

Among 255 NIDDM patients, 93 had DN alone, 69 had NDRD alone, and the remaining 93 had DN plus NDRD (mixed group). The indications for renal biopsy were based on clinical suspicion of superimposed NDRD, including heavy or rapidly increasing proteinuria, renal impairment even though diabetes is of relatively short duration, rapidly declining renal function, and presence of hematuria with dysmorphic red blood cells suggesting presence of glomerulonephritis.

Results

The following were predictors of ESRD: high systolic BP at biopsy, longer duration of diabetes, heavy proteinuria, and presence of diabetic retinopathy. Comparing patients in the NDRD group with the DN group and the mixed group, the NDRD group had lower serum creatinine and higher eGFR with lower urinary proteinuria and higher serum albumin at presentation and on follow-up. Kimmelstiel-Wilson nodules were associated with a poorer prognosis leading to a higher occurrence of ESRD among patients with DN.

Conclusion

Renal biopsy is of value in indicating the prognosis of NIDDM patients with DN based on the diabetic lesions. For NIDDM patients with atypical course and suspicion of associated NDRD, a renal biopsy would enable us to diagnose the underlying NDRD and offer appropriate therapy. Most nephrologists would consider renal biopsy for an NIDDM patient based on clinical indications like atypical clinical course and suspicion of an associated NDRD, but they would not perform a routine renal biopsy like for a CKD patient, unless it is for a research indication.

Timing of kidney biopsy in type 2 diabetic patients: a stepwise approach

BACKGROUND

Diabetic nephropathy (DN) is the most prevalent cause of renal disease in type 2 diabetic patients and is usually diagnosed clinically. A kidney biopsy is considered when non-diabetic renal disease (NDRD) is suspected, such as rapid progression in renal function impairment and severe proteinuria. Still, there is yet no consensus on the timing of kidney biopsy in type 2 diabetic patients. This study aims to identify markers that can help differentiate between DN and NDRD and guide the decision of kidney biopsy.

METHODS

We retrospectively reviewed patients with type 2 diabetes who received kidney biopsy from 2008 to 2017 at Taipei Veterans General Hospital. Ophthalmologist consultation and outpatient records, diagnosis of kidney biopsy, laboratory data, and clinical characteristics were collected.

RESULTS

This study enrolled 160 type 2 diabetic patients, among which 120 (75%) had isolated DN and 40 (25%) had NDRD ± DN (26 had isolated NDRD, and 14 had NDRD superimposed on DN). In multivariate logistic regression analysis, DM duration (odds ratio [OR]: 0.907; 95% confidence interval [CI]: 0.842-0.977; P = 0.01), diabetic retinopathy (OR: 0.196; 95% CI: 0.061-0.627; P = 0.006), and urinary RBC (OR: 1.068; 95% CI: 1.024-1.115; P = 0.002) were independent predictors of NDRD. In patients with diabetic retinopathy (n = 112, 70%), the presence of proliferative diabetic retinopathy, pan-retinal photocoagulation, and hematuria were factors predicting NDRD; and in patients without diabetic retinopathy (n = 48, 30%), short DM duration and hematuria were factors predicting NDRD.

CONCLUSIONS

Using diabetic retinopathy, DM duration, and hematuria, we developed a 3-step approach to stratify patients into three categories with the different likelihoods of having NDRD. Then different strategies could be taken accordingly. Our stepwise approach is easy to follow and may serve as an appropriate and useful tool to help clinicians in making decisions of kidney biopsy in type 2 DM patients presenting with kidney diseases.

Design and validation of a scoring model for differential diagnosis of diabetic nephropathy and nondiabetic renal diseases in type 2 diabetic patients

BACKGROUND

We aim to design a scoring model for differential diagnosis between diabetic nephropathy (DN) and nondiabetic renal disease (NDRD) in type 2 diabetic patients through a combination of clinical variables.

METHODS

A total of 170 patients with type 2 diabetes who underwent kidney biopsies were included and divided into three groups according to pathological findings: DN group (n = 46), MIX group (DN + NDRD, n = 54), NDRD group (n = 70). Clinical characteristics and laboratory data were collected and compared among groups. Variables with a significant statistical difference between DN and NDRD patients were analyzed by logistic regression to predict the presence of NDRD; then a scoring model was established based on the regression coefficient and further validated in an independent cohort of 67 patients prospectively.

RESULTS

On biopsy, 72.9% of patients had NDRD, and the most common pathological type was membranous nephropathy. The established scoring model for predicting NDRD included five predictors: age, systolic blood pressure, hemoglobin, duration of diabetes, and absence of diabetic retinopathy. The model demonstrated good discrimination and calibration (area under curve [AUC] 0.863, 95% CI, 0.800-0.925; Hosmer-Lemeshow [H-L] P = .062). Furthermore, high prediction accuracy (AUC = 0.900; 95% CI, 0.815-0.985) in the validation cohort proved the stability of the model.

CONCLUSIONS

We present a simple, robust scoring model for predicting the presence of NDRD with high accuracy (0.85) for the first time. This decision support tool provides a noninvasive method for differential diagnosis of DN and NDRD, which may help clinicians assess the risk-benefit ratio of kidney biopsy for type 2 diabetic patients with renal impairment.

A Clinicopathological Study of 267 Patients with Diabetic Kidney Disease Based on the Renal Pathology Society - 2010 Classification System

Introduction:

Renal biopsy is primarily indicated in patients with diabetes mellitus (DM) with proteinuria, to diagnose non-diabetic renal disease (NDRD). However, Renal Pathology Society classification (RPSc) – 2010 has classified diabetic nephropathy (DN) into four classes of glomerular lesions with a separate scoring for tubulointerstitial and vascular lesions. Paucity of data from Indian subcontinent prompted us to plan this study to classify DN on biopsy as per the RPSc and correlate the clinical profile with histology.

Materials and Methods:

Patients with DM who underwent renal biopsy for various indications (between Aug 2013 and Nov 2015) were included in the study. DN on histology was classified according to RPSc. Histopathology lesions of DN were correlated with clinical and biochemical profiles.

Results:

Of the 267 patients studied, 252 (94.3%) were type 2 DM. NDRD alone was seen in 65 (24.34%), DN in 161 (60.3%), and NDRD with DN in 41 (15.3%). The most common indications for biopsy were rapidly progressive renal failure (76.7%) and nephrotic syndrome (16.4%). The most common glomerular class was class IV (43.5%), followed class III (41%), class II (13.3%), and class I (1.9%). The most common NDRD seen was acute interstitial nephritis (AIN) in 20.2% and is frequently associated with class III. Tubulointerstitial chronicity and not the arteriolar chronicity, was correlated with low estimated glomerular filtration rate (eGFR).

Conclusions:

Most patients with DN subjected to renal biopsy were in class IV, and AIN was the most common NDRD. Only tubulointerstitial chronicity correlated with low eGFR.

Prevalence of Diabetic Nephropathy among Patients with Type 2 Diabetes Mellitus in China: A Meta-Analysis of Observational Studies

BACKGROUND

Diabetic nephropathy (DN) is an important cause of end-stage renal disease and is recognized as a public health problem worldwide. However, there have been no nationwide surveys of DN prevalence in China. This study is aimed at estimating the pooled prevalence of DN among patients with type 2 diabetes in China.

METHODS

Published studies on the prevalence of DN among patients with type 2 diabetes published from January 1980 to October 2019 were systematically reviewed using PubMed, Embase, Google Scholar, Chinese Wanfang databases, and Chinese National Knowledge Infrastructure. The pooled prevalence of DN was estimated with the random effects model using R software. Prevalence estimates were also stratified by study design, methodological approach, and study population characteristics.

RESULTS

Thirty studies with a total of 79,364 participants were included in our study. The overall pooled prevalence of DN was 21.8% [95% confidence interval (CI): 18.5-25.4%]. Subgroup analysis found that the prevalence of DN varied significantly according to different DM and DN diagnostic criteria (P < 0.05); the pooling estimate was the highest in the west region of 41.3%, followed by that in the east region of China with 22.3%, northeast region with 20.7%, and central region with 15.6% (P < 0.05); the pooling estimate was the highest in the west region of 41.3%, followed by that in the east region of China with 22.3%, northeast region with 20.7%, and central region with 15.6% (P < 0.05); the pooling estimate was the highest in the west region of 41.3%, followed by that in the east region of China with 22.3%, northeast region with 20.7%, and central region with 15.6% (.

CONCLUSIONS

The prevalence of DN is high in Chinese patients with type 2 diabetes and shows geographic and gender variation. These data indicate that national strategies aimed at primary and secondary prevention of DN and screening programs for DN are urgently needed to reduce the risk and burden of DN in China.

The Prevalence of Nondiabetic Renal Diseases in Patients with Diabetes Mellitus in the University Hospital of Ribeirão Preto, São Paulo

OBJECTIVE

To evaluate the prevalence of nondiabetic renal diseases (NDRDs) in renal biopsies of patients with diabetes mellitus (DM) in the University Hospital of Ribeirão Preto, São Paulo. Research Design and Methods. We conducted a retrospective study including kidney biopsies performed in diabetic patients between 1987 and 2013. We evaluated 79 biopsies during this period. The primary variable was the prevalence of NDRD in patients with DM. The secondary variables were the presence of systemic arterial hypertension (SAH), hematuria, time since diagnosis of DM, serum creatinine, and proteinuria levels. The cases were divided into the following groups: isolated diabetic nephropathy (DN-group I), isolated nondiabetic renal diseases (NDRD-group II), associated NDRD/DN (group III), and associated NDRD+NDRD/DN (group IV).

RESULTS

Most of the patients (58.22%) presented only alterations arising from DN. NDRDs were present in 41.77% of the patients. Membranous glomerulonephritis (30.3%) and IgA nephropathy (24.24%) were the most prevalent NDRDs. We found no differences between female and male patients with NDRD when assessing the secondary variables. A time since diagnosis of five years or less revealed a statistical difference (p = 0.0005) in the comparison between the isolated DN (group I) and the NDRD+NDRD/DN (group IV). The other secondary variables were not significant in the comparison of the groups.

CONCLUSIONS

We concluded that the prevalence of NDRD is 41.77%. Membranous glomerulonephritis was the most prevalent NDRD in our study. We also conclude that the probability of the presence of NDRD with or without concomitant DN is greater for patients who had biopsies with a time since diagnosis of five years or less. A time since diagnosis of ten years or more does not allow the exclusion of the presence of NDRD.

Clinical characteristics of diabetic nephropathy in patients with type 2 diabetic mellitus manifesting heavy proteinuria: A retrospective analysis of 220 cases

AIMS

To determine the predictability of diagnosing diabetic nephropathy (DN) versus non-diabetic renal disease (NDRD) from clinical and laboratory data in Chinese patients with type 2 diabetes mellitus (T2DM) manifesting heavy proteinuria.

METHODS

We retrospectively analyzed the clinical and laboratory data of patients with T2DM manifesting heavy proteinuria who underwent renal biopsy from January 2014 to December 2017.

RESULTS

According to renal biopsy, 220 patients were finally enrolled, including 109 cases diagnosed with DN alone (49.55%), 94 with NDRD alone (42.73%) and 17 with DN plus superimposed NDRD (7.73%). Multivariate analysis showed the significant risk factors for DN alone were age, duration of diabetes, presence of retinopathy, 24-h proteinuria, serum albumin and SBP. Presence of retinopathy achieved the highest overall diagnostic efficiency with the area under the curve of 0.852, sensitivity of 78.9% and specificity of 91.5%. The combined diagnosis with four indicators (duration of diabetes, retinopathy, SBP, and serum albumin) showed the area under the curve of 0.938, sensitivity of 88.1% and specificity of 87.2%.

CONCLUSIONS

The prevalence of DN is high in patients with T2DM manifesting heavy proteinuria. Renal biopsy should be performed in diabetics in the atypical clinical scenario.

A Differential Diagnosis Model For Diabetic Nephropathy And Non-Diabetic Renal Disease In Patients With Type 2 Diabetes Complicated With Chronic Kidney Disease

PURPOSE

Differentiating between diabetic nephropathy (DN) and non-diabetic renal disease (NDRD) is difficult and inefficient. The aim of the present study was to create a model for the differential diagnosis of DN and NDRD in patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

We consecutively screened 213 patients with T2DM complicated with chronic kidney disease, who underwent renal biopsy at The First Affiliated Hospital of Guangxi Medical University (Nanning, China) between 2011 and 2017. According to the pathological results derived from the renal biopsy, the patients were divided into three groups (74, 130, and nine in the DN, NDRD, and NDRD superimposed with DN group, respectively). Clinical and laboratory data were compared and a diagnostic model was developed based on the following logistic regression model: logit(P)=+++ … +.

RESULTS

We observed a high incidence of NDRD (61.0% of all patients), including various pathological types; the most common type was idiopathic membranous nephropathy. By comparing clinical variables, we identified a number of differences between DN and NDRD. Logistic regression analyses showed that the following variables were statistically significant: the absence of diabetic retinopathy (DR), proteinuria within the non-nephrotic range, the absence of anemia and an estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m2. We subsequently constructed a diagnostic model for predicting NDRD, as follows: PNDRD=1/[1+exp(-17.382-3.339×DR-1.274×Proteinuria-2.217×Anemia-1.853×eGFR-0.993×DM+20.892Bp)]. PNDRD refers to the probability of a diagnosis of NDRD (a PNDRD≥0.5 predicts NDRD while a PNDRD <0.5 predicts DN); while DM refers to the duration of diabetes. This model had a sensitivity of 95.4%, a specificity of 83.8%, and the area under the receiver operating characteristic curve was 0.925.

CONCLUSION

Our diagnostic model may facilitate the clinical differentiation of DN and NDRD, and assist physicians in developing more effective and rational criteria for kidney biopsy in patients with T2DM complicated with chronic kidney disease.

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.

Identification of clinical predictors of diabetic nephropathy and non-diabetic renal disease in Chinese patients with type 2 diabetes, with reference to disease course and outcome

AIMS

To determine the prevalence of diabetic nephropathy (DN) and non-diabetic renal disease (NDRD) in patients with type 2 diabetes mellitus (T2DM), and the important clinical predictors of renal outcome and clinical course.

METHODS

We conducted a retrospective analysis of clinical, laboratory, and histopathologic data from T2DM patients with renal involvement confirmed by renal biopsy (n = 505). The outcome was defined as the progression to end-stage renal disease (ESRD).

RESULTS

Renal biopsy revealed that 302 patients (59.8%) had DN, 174 (34.5%) had NDRD, and 29 (5.7%) had NDRD superimposed on DN. In multivariate analysis, the absence of diabetic retinopathy (DR) (odds ratio (OR) 4.171, 95% confidence interval (CI) 1.810-9.612; P = 0.001), absence of hypertension (OR 2.412, 95% CI 1.095-5.315; P = 0.029), shorter duration of diabetes (OR 1.015, 95% CI 1.008-1.022; P < 0.001), lower-risk chronic kidney disease (CKD) heat map category (green, yellow and orange) (OR 3.885, 95% CI 1.289-11.707; P = 0.016) and lower glycated hemoglobin (HbA1c) (OR 1.339, 95% CI 1.114-1.610; P = 0.002) were significant clinical predictors of NDRD. Patients with DN had a poorer 5-year renal outcome than those with NDRD, and multivariate analysis identified DN as an independent risk factor for progression to ESRD, when adjusted for important clinical variables (P < 0.05).

CONCLUSIONS

This study has identified the absence of DR and hypertension, lower-risk CKD heat map category, shorter duration of diabetes, and lower HbA1c as useful clinical predictors of NDRD. Renal biopsy is recommended for patients with T2DM and renal disease to obtain an accurate diagnosis and determine timely disease-specific treatment, which should increase the chance of a good renal outcome.

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.

Clinicopathological Features of Nondiabetic Renal Diseases from Different Age Groups: An Observational Cross-sectional Study

Background

Diabetes mellitus (DM) has become the leading cause of chronic kidney disease (CKD). Nondiabetic renal diseases (NDRDs) have different clinicopathological features and prognosis from those of diabetic nephropathy. Our study sought to analyze the clinical and pathological features of NDRDs, in different age groups through a cross-sectional study.

Methods

All patients with type 2 DM at our center who underwent renal biopsy between March 1997 and March 2017 were screened and divided into three groups by age: Group 1 (youth group), 18-44 years old; Group 2 (middle-aged group), 45-59 years old; and Group 3 (elderly group), ≥60 years old. We analyzed the clinicopathological data and risk factors by univariate and multivariate logistic regression for NDRD of the patients to identify the features of NDRD in different age groups.

Results

We included 982 patients in the final analysis. Patients with NDRD accounted for 64.4% of all patients. IgA nephropathy (IgAN) was the most common pathological pattern in young patients with NDRD, accounting for 26.3%. In the middle-aged group, the two most common pathological patterns were IgAN and membranous nephropathy. Membranous nephropathy was the most common pathological pattern in elderly patients with NDRD, accounting for 29.3%. Consistent with pathological features, glomerular hematuria is a risk factor for NDRD in Group 1 (odds ratio [OR], 26.514; 95% confidence interval [CI], 2.503-280.910; P = 0.006). On the other hand, rapidly increasing proteinuria or nephrotic syndrome is a risk factor for NDRD in Group 2 (OR, 5.921; 95% CI, 2.061-17.013; P = 0.001) and Group 3 (OR, 90.409; 95% CI, 6.198-1318.826; P = 0.001).

Conclusions

This single-center study showed that the proportion and composition of NDRD differ among different age groups. Consistent with pathological features, some clinical indices such as hematuria and proteinuria showed different features among different age groups.

Validation of the 2007 kidney disease outcomes quality initiative clinical practice guideline for the diagnosis of diabetic nephropathy and nondiabetic renal disease in Chinese patients

AIMS

Diabetes mellitus (DM) has overtaken infection and immunological factors as the most common cause of end-stage renal disease. The 2007 Kidney Disease Outcomes Quality Initiative (KDOQI) guideline is a widely accepted guideline for the clinical diagnosis of diabetic nephropathy (DN) and non-diabetic renal disease (NDRD). Our study sought to verify its diagnostic ability in the Chinese population.

METHODS

We included 773 patients with DM who underwent a renal biopsy at the Chinese PLA General Hospital from 2007 to 2016. All patients were divided into three groups according to their pathological findings: isolated DN, isolated NDRD, and DN combined with NDRD.

RESULTS

Good sensitivity and poor specificity were found for the prediction of NDRD in the Chinese population. Rapidly decreasing estimated glomerular filtration rate, systemic disease, refractory hypertension, and the existence of "grey area" patients may have contributed to the poor diagnostic ability.

CONCLUSIONS

The diagnostic ability of the 2007 KDOQI guideline for DN and NDRD was unsatisfactory. The high sensitivity and low specificity of the guideline made it more suitable as screening criteria rather than as diagnostic criteria.

Non-diabetic renal disease in patients with type 2 diabetes: a single centre study

BACKGROUND

Non-diabetic renal disease (NDRD) has been widely known in diabetic patients. The clinical differentiation between diabetic nephropathy (DN) and NDRD is still not so clear and effective.

AIM

To analyse the pathological characteristics and distribution of renal injury in selected type 2 diabetic patients. Comparison between DN and NDRD in clinical characteristics, to find important predictors for NDRD.

METHODS

To conduct retrospective analysis of clinical, laboratory and pathohistological data of type 2 diabetic patients in whom renal biopsies were performed from March 2010 to September 2014 in Shandong Provincial Hospital affiliated to Shandong University (n = 88).

RESULTS

According to the findings of renal biopsy, the incidences of DN, NDRD and DN complicated with NDRD were 20.46, 72.73 and 6.82% respectively. The most common NDRD found were: membranous nephropathy, followed by IgA nephropathy and focal segmental glomerulosclerosis. In multivariate logistic-analysis, fasting blood glucose (odds ratio (OR) 0.714; 95% confidence interval (CI) = 0.543-0.939; P = 0.016) and absence of diabetic retinopathy (OR 18.602; 95% CI = 2.176-159.018; P = 0.003) were independent predictors of NDRD.

CONCLUSIONS

This study confirmed a considerably high prevalence of NDRD in type 2 diabetic patients with renal injury. As some cases of NDRD are readily treatable or remittable, we should consider renal biopsy in selected diabetic patients with renal involvement, especially in those with effective blood glucose control and the absence of diabetic retinopathy.

Accuracy of hematuria for predicting non-diabetic renal disease in patients with diabetes and kidney disease: A systematic review and meta-analysis

AIMS

To clarify the predictive value of hematuria in patients with diabetes and non-diabetic renal disease (NDRD).

METHODS

The databases of Medline, Embase and the Cochrane Library were searched up to November 22, 2017. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR, NLR), diagnostic odds ratio (DOR), and area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated using a bivariate mixed-effects regression model.

RESULTS

Thirty-eight articles were eligible, of which 35 articles with 4005 patients investigated hematuria. The pooled sensitivity and specificity of hematuria to predict NDRD were 0.42 (95% CI 0.35-0.49) and 0.72 (95% CI 0.64-0.79), respectively. The pooled PLR and NLR were 1.49 (95% CI 1.28-1.75) and 0.81 (95% CI 0.75-0.87), respectively. The DOR was 1.85 (95% CI 1.49-2.30). The pooled AUC was 0.59 (95% CI 0.54-0.63). For dysmorphic erythrocytes, the pooled sensitivity was 0.27 (95% CI 0.23-0.32), while the specificity was 0.94 (95% CI 0.91-0.97). There was heterogeneity among studies (p < 0.001), and no publication bias was identified.

CONCLUSIONS

Type 2 diabetes patients presenting with hematuria are slightly more likely to develop NDRD. Dysmorphic erythrocytes may be more useful than microhematuria in diagnosing for NDRD in type 2 diabetes with proteinuria.

Diabetic Microvascular Disease: An Endocrine Society Scientific Statement

Both type 1 and type 2 diabetes adversely affect the microvasculature in multiple organs. Our understanding of the genesis of this injury and of potential interventions to prevent, limit, or reverse injury/dysfunction is continuously evolving. This statement reviews biochemical/cellular pathways involved in facilitating and abrogating microvascular injury. The statement summarizes the types of injury/dysfunction that occur in the three classical diabetes microvascular target tissues, the eye, the kidney, and the peripheral nervous system; the statement also reviews information on the effects of diabetes and insulin resistance on the microvasculature of skin, brain, adipose tissue, and cardiac and skeletal muscle. Despite extensive and intensive research, it is disappointing that microvascular complications of diabetes continue to compromise the quantity and quality of life for patients with diabetes. Hopefully, by understanding and building on current research findings, we will discover new approaches for prevention and treatment that will be effective for future generations.

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.

Clinical and pathological characteristics of non-diabetic renal disease in type 2 diabetes patients

Background

Renal involvement in type 2 diabetes is mainly due to diabetic nephropathy (DN). Nevertheless, a sizable proportion of diabetic patients could actually have nondiabetic renal diseases (NDRDs) or DN plus NDRDs. This study aimed to explore the pathological features of NDRD in diabetic patients and to assess the predictability of diagnosing NDRD (±DN) versus isolated DN on the basis of clinical parameters.

Methods

Medical records of type 2 diabetes patients who underwent renal biopsy under suspicion of NDRD from January 2011 through November 2015 were analyzed retrospectively.

Results

A total of 101 patients were enrolled in this study. The most frequent indication for renal biopsy was recent onset of nephrotic syndrome (41%), followed by rapidly progressive renal failure (29%) and active urinary sediment (21%). On renal biopsy, 51% of patients had isolated DN, 20% had isolated NDRD and 29% had DN plus NDRD. IgA nephropathy was the most common cause of isolated NDRD, whereas acute tubular necrosis (39%) and acute interstitial nephritis (33%) were the main causes of NDRD superimposed on DN. Male gender, short-duration diabetes (<8 years), lower glycated hemoglobin and active urinary sediment (≥10 red and white blood cells per high-power field) were independent predictors of NDRD according to multiple logistic regression analysis.

Conclusions

Judicious use of renal biopsy revealed NDRD (±DN) in nearly half of type 2 diabetes patients with atypical renal presentation, especially in male patients with well-controlled diabetes, those who have had diabetes for a short duration and those with active urinary sediment.

Renal pathological implications in type 2 diabetes mellitus patients with renal involvement

AIMS

To investigate the renal pathological implications in type 2 diabetes mellitus patients with renal involvement.

METHODS

A total of 328 type 2 diabetes mellitus (T2DM) patients with renal involvement who underwent a renal biopsy and received follow-up for at least one year were recruited in our study. The patients were divided into the diabetic nephropathy (DN), non-diabetic renal disease (NDRD), and NDRD superimposed on DN groups based on the pathological diagnosis. Renal outcomes were defined by the initiation of renal replacement therapy or doubling of the serum creatinine. Kaplan-Meier analysis was used to compare renal survival, and Cox proportional hazard analysis was used to determine the predictors of renal outcomes in the DN group.

RESULTS

Renal biopsy findings revealed that 188 patients (57.32%) had pure DN, 121 patients (36.89%) had NDRD alone, and 19 patients (5.79%) had NDRD superimposed on DN. The most frequent subclassification of NDRD was membranous nephropathy (MN). Compared with the NDRD and NDRD superimposed on DN groups, patients with pure DN had poorer renal function and lower renal survival rates. In the DN group, the five-year renal survival rates of glomerular classes of I, IIa, IIb, III and IV were 100%, 84.62%, 60%, 47.5% and 33.33%, respectively. Multivariate Cox proportional hazard analysis showed that the glomerular lesions, proteinuria and serum creatinine were independent risk factors for renal outcomes, while interstitial fibrosis/inflammation and arteriolar hyalinosis were not independently associated with renal outcomes in the DN group.

CONCLUSIONS

Making an accurate pathologic diagnosis by renal biopsy is crucial for diabetes mellitus (DM) patients with renal involvement. The findings of our present study indicated that patients with pure DN had poorer renal outcomes than patients with NDRD or NDRD superimposed on DN. The classification of glomerular lesions, proteinuria and serum creatinine were independent risk factors for renal outcomes in the DN group. More studies with large samples and longer time follow-up are needed to evaluate the relationship between pathological changes and clinical characteristics in T2DM patients who have renal involvement.

Classification and Differential Diagnosis of Diabetic Nephropathy

Diabetic nephropathy (DN) is a major cause of end-stage renal disease throughout the world in both developed and developing countries. This review briefly introduces the characteristic pathological changes of DN and Tervaert pathological classification, which divides DN into four classifications according to glomerular lesions, along with a separate scoring system for tubular, interstitial, and vascular lesions. Given the heterogeneity of the renal lesions and the complex mechanism underlying diabetic nephropathy, Tervaert classification has both significance and controversies in the guidance of diagnosis and prognosis. Applications and evaluations using Tervaert classification and indications for renal biopsy are summarized in this review according to recent studies. Meanwhile, differential diagnosis with another nodular glomerulopathy and the situation that a typical DN superimposed with a nondiabetic renal disease (NDRD) are discussed and concluded in this review.

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.

Predictive factors for non-diabetic nephropathy in diabetic patients. The utility of renal biopsy

BACKGROUND AND OBJECTIVES

Diabetic renal lesions can only be diagnosed by kidney biopsy. These biopsies have a high prevalence of non-diabetic lesions. The aims of the study were to determine the predictability of non-diabetic nephropathy (NDN) in diabetics and study differences in survival and renal prognosis. In addition, we evaluated histological lesions and the effect of proteinuria on survival and renal prognosis in patients with diabetic nephropathy (DN).

MATERIAL AND METHODS

A descriptive, retrospective study of kidney biopsies of diabetics between 1990 and 2013 in our centre.

RESULTS

110 patients were included in the study: 87 men (79%), mean age 62 years (50-74), mean serum creatinine 2.6mg/dl (0.9-4.3) and proteinuria 3.5g/24hours (0.5-6.5). 61.8% showed NDN, 34.5% showed DN and 3,6% showed DN+NDN. The most common NDN was IgA nephropathy (13,2%). In the multivariate analysis, creatinine (OR: 1.48, 1.011-2.172, p=0.044), proteinuria/24hours (OR: 0.813, 0.679-0.974, p=0.025), duration of diabetes (OR: 0.992, 0.987-0.998, p=0.004), age (OR: 1.068, 95% CI: 1.010-1.129, p=0.022), and diabetic retinopathy (OR: 0.23, 0.066-0.808, p=0.022) were independently associated with NDN. We did not find any differences in survival or renal prognosis. Concerning patients with DN, increased nodular mesangial expansion (p=0.02) and worse renal prognosis (p=0.004) were observed in nephrotic proteinuria as compared to non-nephrotic proteinuria. We did not find differences in patient survival.

CONCLUSIONS

The most common cause of NDN was IgA nephropathy. Higher creatinine levels, shorter duration of diabetes, absence of diabetic retinopathy, lower proteinuria, and older age were risk factors for NDN. Patients with DN and nephrotic-range proteinuria had worse renal prognosis.

Persistent Albuminuria in Children with Type 2 Diabetes: A Canadian Paediatric Surveillance Program Study

OBJECTIVE

To determine the prevalence and the clinical features associated with persistent albuminuria in Canadian children aged <18 years with type 2 diabetes.

STUDY DESIGN

This national prospective surveillance study involved a network of pediatricians and pediatric endocrinologists. Cases of persistent albuminuria in children with type 2 diabetes were reported during a 24-month period from 2010 to 2012. Persistent albuminuria was defined as an elevated albumin-to-creatinine ratio in a minimum of 2 out of 3 urine samples obtained at least 1 month apart over 3-6 months and confirmed with a first morning sample. Descriptive statistics were used to illustrate demographic and clinical features of the population. The prevalence of persistent albumuria was estimated using data from a previous national surveillence study of type 2 diabetes in children.

RESULTS

Fifty cases were reported over the 24-month study period. The estimated prevalence of persistent albuminuria in children with type 2 diabetes in Canada was 5.1%. The median duration of diabetes at the time of diagnosis of albuminuria was 21 days (IQR, 0-241 days). Almost two-thirds (64%) were female, 80% were of Canadian First Nations heritage, and 76% were from Manitoba. Exposure to gestational or pregestational diabetes in utero occurred in 65%, and 48% had a family history of diabetes-related renal disease. Structural anomalies of the kidney were found in 37%.

CONCLUSION

Persistent albuminuria occurs in youths with type 2 diabetes in the first year after diagnosis, demonstrates regional variation, and is associated with First Nations heritage and exposure to maternal diabetes during pregnancy.

Clinical factors associated with the diagnosis and progression of diabetic nephropathy

As an important complication of diabetic mellitus, diabetic nephropathy (DN) has been the main cause of end-stage renal disease. It is of great importance to diagnose DN early, and to identify the risk factors of disease progression in order to carry out in-time and effective therapies. Previous literatures have reported the role of several clinical factors in the diagnosis and progression of DN, including age, longer diabetes duration, diabetic retinopathy, higher level of hypertension and HbA1c, and so on. However, the significance of these clinical factors is still controversial and limited. This review aimed to evaluate the values and limitations of these factors in diagnosing and predicting the renal outcome of DN.

Estimated glomerular filtration rate progression in UK primary care patients with type 2 diabetes and diabetic kidney disease: a retrospective cohort study

AIMS

To examine the rates of diabetic kidney disease (DKD) progression and associated factors, we undertook a study of estimated glomerular filtration rate (eGFR) in a historical cohort of UK primary care patients with type 2 diabetes mellitus (T2DM) and associated DKD from the Clinical Practice Research Datalink.

METHODS

Our eligible population were patients with definitive T2DM from a recorded diagnostic code with either a diagnosis of chronic kidney disease (CKD) or renal function test values and renal abnormalities consistent with a CKD diagnosis, identified between 1 October 2006 and 31 December 2011. Only patients with albuminuria results reported in mg/l were used for the longitudinal statistical analyses of the eGFR rate of change using multilevel models.

RESULTS

We identified 111,030 patients with T2DM. Among them 58.6% (95% confidence interval (CI): 58.3-58.9) had CKD and 37.2% (95% CI: 36.9-37.5%) had presumed DKD at baseline. Only 19.4% of patients had urinary albumin test results expressed as mg/l in the year prior to index date. Almost two-thirds (63.8%) of patients with T2DM and presumed DKD received prescriptions for angiotensin-converting enzyme (ACE) inhibitors or angiotensin type 1 receptor blockers (ARB) or both. Time-dependent variables that predict subsequent eGFR decline include increased albuminuria, time from index date and older age.

CONCLUSION

Only a minority of diabetic patients with DKD had quantitative albuminuria assessments. The relatively low proportion of DKD patients with ACEi or ARB prescriptions suggests a gap between healthcare practice and available scientific evidence during the study period. Increased albuminuria and older age were the most consistent predictors of subsequent eGFR decline.

Less known pathophysiological mechanisms of anemia in patients with diabetic nephropathy

Diabetes mellitus (DM) is currently considered a modern global epidemic, and diabetic nephropathy (DN) is the most common cause of chronic kidney disease (CKD). Anemia is one of the most significant complications of CKD, and it is mainly attributed to insufficient erythropoietin (EPO) production. However, anemia develops earlier in the course of CKD among patients with DM, and the severity of anemia tends to be more marked in these patients compared to nondiabetic subjects, regardless of the stage of CKD. In this review, we focus on the "less known" complex interacting mechanisms which are involved in the pathophysiology of anemia associated with DN. Although the major cause of anemia in DN is considered to be an inappropriate response of the plasma EPO concentration to anemia, several other possible mechanisms have been suggested. Glomerular hyperfiltration, proteinuria, renal tubular dysfunction and interstitial fibrosis are among the main culprits. On the other hand, systemic effects such as chronic inflammation, autonomic neuropathy and the renin-angiotensin system are also involved. Finally, several medications are considered to aggravate anemia associated with DN. Since anemia is an important predictor of quality of life and is implicated in the increased burden of cardiovascular morbidity and mortality, further research is required to elucidate its pathogenesis in diabetic patients.

Spectrum of renal disease in diabetes

The spectrum of renal disease in patients with diabetes encompasses both diabetic kidney disease (including albuminuric and non-albuminuric phenotypes) and non-diabetic kidney disease. Diabetic kidney disease can manifest as varying degrees of renal insufficiency and albuminuria, with heterogeneity in histology reported on renal biopsy. For patients with diabetes and proteinuria, the finding of non-diabetic kidney disease alone or superimposed on the changes of diabetic nephropathy is increasingly reported. It is important to identify non-diabetic kidney disease as some forms are treatable, sometimes leading to remission. Clinical indications for a heightened suspicion of non-diabetic kidney disease and hence consideration for renal biopsy in patients with diabetes and nephropathy include absence of diabetic retinopathy, short duration of diabetes, atypical chronology, presence of haematuria or other systemic disease, and the nephrotic syndrome.

Non-diabetic renal diseases in a multi-ethnic New Zealand cohort with type 2 diabetes mellitus: clinical and histopathological features

The aims of this study were to identify non-diabetic renal disease (NDRD), including obesity related glomerulopathy (ORG) in diabetic patients, and compare the findings with those of pure diabetic nephropathy (DN).Ninety-three renal biopsies from diabetic patients were reviewed retrospectively, along with their clinical findings at biopsy and their estimated glomerular filtration rate (eGFR) over 5 years follow-up. DN and focal segmental glomerulosclerosis (FSGS) were diagnosed on blinded histology review, together with assessment of renal compartment histology. Other NDRD were diagnosed on full review.Most patients were obese with poor renal function at biopsy. NDRD occurred in more than two-thirds of biopsies. FSGS and interstitial nephritis were common. Patients with pure FSGS presented earlier, and had favourable histological features and clinical course. Most FSGS patients fulfilled criteria for ORG. Biopsies with interstitial nephritis showed more functional glomerular tissue, and most patients retained good renal function. Adverse prognostic features were DN versus NDRD, nodular grade of DN, low eGFR at biopsy, and severe chronic histological changes.In this population, ORG mechanisms contribute to renal injury. FSGS is frequent, and should be diagnosed separately from any DN. Biopsy to confirm suspicion of interstitial nephritis should be performed even if retinopathy is present.

Non-diabetic renal disease in Croatian patients with type 2 diabetes mellitus

AIM

Our study aimed to examine the prevalence of non-diabetic renal disease in selected patients with type 2 diabetes mellitus and to determine important risk factors for non-diabetic renal disease.

METHODS

We conducted retrospective analysis of clinical, laboratory and pathohistological data of type 2 diabetes mellitus patients in whom renal biopsies were performed from January 2004 to February 2013 at Dubrava University Hospital Zagreb Croatia (n=80).

RESULTS

According to renal biopsy findings, isolated diabetic nephropathy was found in 46.25%, non-diabetic renal disease superimposed on diabetic nephropathy in 17.5% and isolated non-diabetic renal disease in 36.25% of the patients. The most common non-diabetic renal diseases found were: membranous nephropathy, followed by IgA nephropathy and focal segmental glomerulosclerosis. In univariate analysis shorter duration of diabetes, independence of insulin therapy, lower levels of HbA1c and absence of diabetic retinopathy were found to be significant clinical predictors of non-diabetic renal disease. In multivariate analysis only independence of insulin therapy (OR 4.418, 95%CI=1.477-13.216) and absence of diabetic retinopathy (OR 5.579, 95%CI=1.788-17.404) were independent predictors of non-diabetic renal disease.

CONCLUSIONS

This study confirmed usefulness of renal biopsy in patients with type 2 diabetes mellitus, due to the high prevalence of non-diabetic renal disease found. Since non-diabetic renal disease are potentially curable, we should consider renal biopsy in selected type 2 diabetes mellitus patients with renal involvement, especially in those with absence of diabetic retinopathy and independence of insulin therapy.

Recurrence of glomerulonephritis after renal transplantation

Recurrence of glomerulonephritis following renal transplantation is considered an important cause of allograft failure. The incidence of recurrence of glomerulonephritis varies widely depending on the definition of recurrence (pathologic recurrence or clinicopathologic recurrence) and the original glomerular disease. Moreover the impact of recurrence of glomerular disease on allograft outcome varies widely between different forms of glomerulonephritis. Whereas IgA nephritis recurs in up to one third of transplanted patients, this is not associated with adverse effects on graft survival. In contrast, recurrent focal segmental glomerulosclerosis and membranoproliferative glomerulopathy have an unfavorable prognosis. Overall, long-term graft survival in patients transplanted for glomerulonephritis is comparable to survival in patients with other causes of ESRD. In recent years, several mechanisms for recurrent disease after transplantation (e.g. PLA2R antibodies in membranous nephropathy and suPAR in FSGS) have been identified, and these findings have helped to elucidate the pathogenesis of glomerular diseases. Although renal transplantation is the treatment of choice for end-stage renal disease as a consequence of glomerulonephritis, further studies are required to develop optimal strategies to prevent, diagnose and treat recurrent glomerular diseases.

The modern spectrum of renal biopsy findings in patients with diabetes

BACKGROUND AND OBJECTIVES

Renal biopsies performed in diabetic patients are increasing in number and complexity. This study sought to determine the usefulness of renal biopsy in patients with diabetes and the predictability of diagnosing diabetic nephropathy (DN) versus nondiabetic renal disease (NDRD) from clinical and laboratory data.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

To assess modern trends, a retrospective study was performed of clinical-pathologic findings in all patients with diabetes who had a biopsy in 2011. Among 2642 native kidney biopsies, 620 (23.5%) were from patients with diabetes.

RESULTS

The cohort included 371 men (60.7%) aged a median (interquartile range) 62 years (52-69) with 10-year (5-15) duration of diabetes mellitus (DM). Median serum creatinine was 2.5 mg/dl (1.6-4.4), and 52% of patients had stage 4-5 CKD. On biopsy, 37% of patients had DN alone, 36% had NDRD alone, and 27% had DN plus NDRD. In NDRD alone, FSGS (22%), hypertensive nephrosclerosis (18%), acute tubular necrosis (ATN) (17%), IgA nephropathy (11%), membranous GN (8%), and pauci-immune GN (7%) comprised 80% of diagnoses, compared with ATN (43%), hypertensive nephrosclerosis (19%), FSGS (13%), and IgA nephropathy (7%) for DN plus NDRD. In multivariate analyses, longer duration of DM was associated with a greater likelihood of DN and a lower likelihood of NDRD: each added year of DM reduced the odds of NDRD by 5% (odds ratio, 0.95; 95% confidence interval, 0.91 to 0.98; P=0.004). DM duration ≥ 12 years was the best predictor (58% sensitivity, 73% specificity) of DN alone.

CONCLUSIONS

Approximately one-quarter of all renal biopsies are performed in patients with DM. Judicious use of renal biopsy has uncovered NDRD alone or superimposed on DN in the majority of such biopsies. ATN is emerging as an important category of NDRD, which has not been reported previously.