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

Non-diabetic nephropathy in diabetic patients: incidence, HbA1c variability and other predictive factors, and implications

PURPOSE

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD) in the population. In patients with diabetes mellitus, the incidence of non-diabetic nephropathy (NDNP) has been estimated to range from 3% to 69.5%. Personal judgment is frequently employed while deciding whether or not to do a kidney biopsy (KB) on diabetic patients. NDNP alters the prognosis and course of treatment for people with DM. In our study, we examined the incidence of NDNP concurrent with the progression of diabetes mellitus, as well as the laboratory and clinical indicators that could be utilized to forecast it.

METHODS

A retrospective analysis of 76 diabetic patients who underwent KB was conducted. Based on the pathological diagnoses of these patients, they were categorized as DNP (diabetic nephropathy) or NDNP. The definition of HbA1c variability was determined by calculating the mean HbA1c and the average value of the HbA1c measurements, as well as the standard deviation (SD) for each participant.

RESULTS

NDNP was detected in 50% of 76 patients. Among patients with NDNP, 36.8% had focal segmental glomerulosclerosis (FSGS), 23.6% had membranous glomerulonephritis, and 7.8% had IgA nephritis. The NDNP group exhibited significantly higher rates of female gender, absence of diabetic retinopathy, shorter time to diagnosis of diabetes mellitus, chronic kidney disease, and proteinuria, less intensive medication for diabetes mellitus, presence of hematuria and leukociduria, immunological serological marker positivity, and non-HbA1C variability. Risk factors for predicting non-diabetic nephropathy, as determined by multivariate analysis, included female gender, the absence of diabetic retinopathy, non-HbA1c variability and a positive immunological serological test.

CONCLUSION

In this study, a significant number of diabetic patients with chronic kidney disease were diagnosed with NDNP. Identifying these patients allows for treatment of the specific underlying disease. Factors such as the absence of DR, non-HbA1c variability, female gender, and immunological serological test positivity can predict NDNP and guide the clinician's decision on kidney biopsy. Further prospective studies are warranted to validate the efficacy of potential predictive factors like HbA1c variability.

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

When to Suspect Non-diabetic Kidney Disease in a Diabetic Patient?

The diagnosis of non-diabetic kidney disease (NDKD) in a diabetic patient has significant therapeutic and prognostic implications. There are certain proven clinical predictors of NDKD, which, when present in an appropriate clinical setting, would warrant a kidney biopsy. Herein, we describe four cases of NDKD diagnosed in rather unusual clinical settings, which add to the list of clinical predictors of NDKD. The first case was a “parainfectious glomerulonephritis” diagnosed in a 50-year-old diabetic woman who presented with persistent renal dysfunction despite successful treatment of urinary tract infection. The second case was “membranous nephropathy” diagnosed in a 43-year-old man with long-standing type 1 diabetes, which was associated with other microvascular complications. In this case, the only predictor was disproportionately low serum albumin. The third case was “amyloid light chain (AL) amyloidosis” diagnosed in an elderly diabetic who presented with progressive anasarca over six months. In this case, the only clinical predictor was a disassociation observed between urine dipstick and 24-hour protein estimation. In the fourth case, an elderly diabetic woman without underlying diabetic retinopathy presented with sudden onset nephrotic syndrome. A kidney biopsy was suggestive of diffuse nodular glomerulosclerosis. Immunofluorescence and electron microscopic evaluation were diagnostic of “gamma heavy chain deposition disease.” In all four cases, diagnosis of NDKD led to major therapeutic changes and attainment of renal remission. We have extensively reviewed all major biopsy cohorts of NDKD and have formulated an approach to the diagnosis of NDKD.

New Diagnostic Model for the Differentiation of Diabetic Nephropathy From Non-Diabetic Nephropathy in Chinese Patients

BACKGROUND

The disease pathology for diabetes mellitus patients with chronic kidney disease (CKD) may be diabetic nephropathy (DN), non-diabetic renal disease (NDRD), or DN combined with NDRD. Considering that the prognosis and treatment of DN and NDRD differ, their differential diagnosis is of significance. Renal pathological biopsy is the gold standard for diagnosing DN and NDRD. However, it is invasive and cannot be implemented in many patients due to contraindications. This article constructed a new noninvasive evaluation model for differentiating DN and NDRD.

METHODS

We retrospectively screened 1,030 patients with type 2 diabetes who has undergone kidney biopsy from January 2005 to March 2017 in a single center. Variables were ranked according to importance, and the machine learning methods (random forest, RF, and support vector machine, SVM) were then used to construct the model. The final model was validated with an external group (338 patients, April 2017-April 2019).

RESULTS

In total, 929 patients were assigned. Ten variables were selected for model development. The areas under the receiver operating characteristic curves (AUCROCs) for the RF and SVM methods were 0.953 and 0.947, respectively. Additionally, 329 patients were analyzed for external validation. The AUCROCs for the external validation of the RF and SVM methods were 0.920 and 0.911, respectively.

CONCLUSION

We successfully constructed a predictive model for DN and NDRD using machine learning methods, which were better than our regression methods.

CLINICAL TRIAL REGISTRATION

ClinicalTrial.gov, NCT03865914.

Kidney Biopsy in Type 2 Diabetes: A Multicenter Cross-Sectional Study

INTRODUCTION

Kidney biopsies (KBs) are performed in patients with type 2 diabetes (T2D) to diagnose non-diabetic or hypertensive kidney disease (NDHKD) potentially requiring specific management compared to diabetic and or hypertensive nephropathy (absence of NDHKD). Indications for KB are based on the presence of atypical features compared to the typical course of diabetic nephropathy. In this study, we assessed the association of different patterns of atypical features, or KB indications, with NDHKD.

METHODS

Native KBs performed in patients with T2D were analyzed. Data were collected from the patients' records. KB indications were determined according to the presence of different atypical features considered sequentially: (1) presence of any feature suggesting NDHKD which is not among the following ones, (2) recent onset of nephrotic syndrome, (3) low or rapidly declining estimated glomerular filtration rate (eGFR), (4) rapid increase in proteinuria, (5) short duration of diabetes, (6) presence of hematuria, or (7) normal retinal examination.

RESULTS

Among the 463 KBs analyzed, NDHKD was diagnosed in 40% of the total population and 54, 40, 24, and 7% of the KBs performed for indications 1-4 respectively. Conversely, no patient who underwent KB for indications 5-7 displayed NDHKD. Logistic regression analyses identified eGFRCKD-EPI >15 mL/min/1.73 m2, urinary protein-to-Cr ratio <0.3 g/mmol, hematuria, HbA1c <7%, and diabetes duration <5 years as predictors of NDHKD, independently from the indication group.

CONCLUSION

NDHKD is frequent in T2D. Despite the association of hematuria with NDHKD, our results suggest that presence of hematuria and absence of DR are insufficient to indicate KB in the absence of concurrent atypical features. Conversely, rapid progression of proteinuria and rapid deterioration of eGFR are major signals of NDHKD.

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.

Indications for renal biopsy in patients with diabetes. Joint position statement of the Italian Society of Nephrology and the Italian Diabetes Society

AIMS

This joint document of the Italian Society of Nephrology and the Italian Diabetes Society reviews the main indications to perform a renal biopsy in diabetic patients, according to the recommendations of a panel of experts based on all available scientific evidence.

DATA SYNTHESIS

Renal biopsy has a pivotal role in assessing the nature and severity of renal injury in patients with diabetic kidney disease (DKD). The procedure is mandatory in the presence of one of more of the following features: rapid onset or progression of albuminuria or sudden onset of nephrotic syndrome, rapid GFR decline with or without albuminuria, hematuria, active urine sediment, clinical and/or laboratory suspicion of other systemic diseases, and, in patients with type 1 diabetes, short diabetes duration and absence of retinopathy. Indeed, ~40% of diabetic individuals with kidney injury undergoing renal biopsy are affected by a non-diabetic renal disease (NDRD). Furthermore, the histological evaluation of patients with suspected classical diabetic nephropathy allows to define the extent of glomerular, tubulo-interstitial and vascular lesions, thus providing important prognostic (and potentially therapeutic) data. In the future, the indications for renal biopsy might be extended to the definition of the histological lesions underlying the "nonalbuminuric" DKD phenotypes, as well as to the evaluation of the response to treatment with the new anti-hyperglycemic drugs that provide cardiorenal protection.

CONCLUSIONS

In view of the heterogeneous clinical presentation and course of DKD and of the related heterogeneous histopathological patterns, a more extensive use of renal biopsy may be crucial to provide valuable information with important pathogenic, diagnostic, prognostic, and therapeutic implications.

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.

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.

Diabetic Kidney Disease: Past and Present

Diabetes mellitus (DM) afflicting humans has been recognized as a disease for >3000 years. However, very little was known about its etiology and pathogenesis until about a century ago when increasing knowledge about anatomy and physiology of the human body gradually led to our understanding that the hormone insulin produced by the Islets of Langerhans in the pancreas plays a crucial role in the metabolism of glucose and maintaining the blood sugar level within a normal range. DM is caused by inadequate insulin production (type 1) or insulin resistance (type 2). For thousands of years, DM has been considered as a disease of the kidney; however, with the understanding of the pathogenesis of DM, it became clear that diabetic kidney disease (DKD) is a complication and not a cause of DM. DKD is associated with increased matrix expansion that manifests morphologically as a diffuse or nodular expansion of the mesangium and diffuse thickening of the glomerular and tubular basement membranes. Hyperglycemia plays a crucial role in the development of pathologic changes within the kidney. Once established, DKD usually undergoes a slow but relentless progression to end-stage renal disease. However, recent studies have shown that its progression can be slowed or even reversed by strict control of hyperglycemia. Morphologically, DKD may resemble several other glomerular diseases that must be ruled out before a definitive diagnosis. Patients with DM may also develop nondiabetic glomerular or interstitial diseases with or without DKD. The findings in nephrectomy specimens and the differential diagnoses are presented in detail.

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.

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.

When to perform renal biopsy in patients with type2 diabetes mellitus? Predictive model of non-diabetic renal disease

INTRODUCTION

Diabetic nephropathy (DN) is one of the most frequent complications in patients with diabetes mellitus (DM) and its diagnosis is usually established on clinical grounds. However, kidney involvement in some diabetic patients can be due to other causes, and renal biopsy might be needed to exclude them. The aim of our study was to establish the clinical and analytical data that predict DN and no-diabetic renal disease (NDRD), and to develop a predictive model (score) to confirm or dismiss DN.

MATERIAL AND METHODS

We conducted a transversal, observational and retrospective study, including renal biopsies performed in type2 DM patients, between 2000 and 2018.

RESULTS

Two hundred seven DM patients were included in our study. The mean age was 64.5±10.6 years and 74% were male. DN was found in 126 (61%) of the biopsies and NDRD in 81 (39%). Diabetic retinopathy was presented in 58% of DN patients, but only in 6% of NDRD patients (P<.001). Patients with NDRD were diagnosed of primary glomerulopathies (52%), nephroangiosclerosis (16%), inmunoallergic interstitial nephritis (15%) and vasculitis (8.5%). In the multivariate analysis, retinopathy (OR26.7; 95%CI: 6.8-104.5), chronic ischaemia of lower limbs (OR4,37; 95%CI: 1.33-14.3), insulin therapy (OR3.05; 95%CI: 1.13-8.25), time course of DM ≥10years (OR2.71; 95%CI: 1.1-6.62) and nephrotic range proteinuria (OR2.91; 95%CI: 1.2-7.1) were independent predictors for DN. Microhaematuria defined as ≥10 red blood cells per high-power field (OR0.032; 95%CI: 0.01-0.11) and overweight (OR0.21; 95%CI: 0.08-0.5) were independent predictors of NDRD. According to the predictive model based on the multivariate analysis, all patients with a score >3 had DN and 94% of cases with a score ≤1 had NDRD (score ranked from -6 to 8points).

CONCLUSIONS

NDRD is common in DM patients (39%), being primary glomerulonephritis the most frequent ethology. The absence of retinopathy and the presence of microhematuria are highly suggestive of NDRD. The use of our predictive model could facilitate the indication of performing a renal biopsy in DM patients.

[Criteria to indicate kidney biopsy in type 2 diabetic patients with proteinuria: Survey among French nephrologists]

Diabetic nephropathy is usually a presumptive diagnosis based on clinical and biological evidence. Renal biopsies are performed in diabetic patients with atypical findings evoking non-diabetic renal disease who could benefit from specific therapies. French speaking nephrologists were asked which criteria they retain to indicate renal biopsy in patients with type 2 diabetes and albuminuria>0.5g/day or equivalent through an online anonymous questionnaire. Among the suggested criteria were absence of diabetic retinopathy, hematuria, rapid decrease in GFR, short diabetes duration or rapid raise of proteinuria. 188 people answered the poll among whom interns (12%), fellows (13%), university hospital practitioners (26%), general hospital practitioners (24%), practitioners in a non-profit organization (13%), practitioners on private activity (10%), multi-modal practitioners (3%) and people without clinical activity (2%). Increasing proteinuria was retained as an indication criterion for renal biopsy by 51% of respondents, nephrotic syndrome by 56% of respondents, absence of diabetic retinopathy by 57% of respondents, short diabetes duration by 65% of respondents, rapid GFR decline by 75% of respondents and hematuria by 78% of respondents. These data highlight the high diversity of opinions on this topic and their discrepancies with guidelines and current literature regarding the association between non-diabetic renal disease and clinical and biological features. The lack of adhesion of nephrologists to guidelines was especially noteworthy regarding the absence of diabetic retinopathy. These results emphasize the need for studies focusing on biopsy indication criteria in patients with type 2 diabetes.

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.

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.

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.

Hematuria and Renal Outcomes in Patients With Diabetic Chronic KidneyDisease

BACKGROUND

Hematuria may indicate nondiabetic renal disease in diabetic chronic kidney disease (CKD). However, some studies have reported that hematuria is noted in diabetic nephropathy and is associated with albuminuria. Hematuria is a risk factor for end-stage renal disease in glomerulonephritis, but its prognostic value in diabetic CKD is unknown. We investigated the factors associated with hematuria and the prognostic value of hematuria in patients with diabetic CKD.

MATERIAL AND METHODS

We included 1958 patients with type 2 diabetes and CKD stages 1-5, and 111 patients underwent renal biopsy. Patients in the biopsied cohort were younger and had more severe proteinuria, compared with those in the total cohort; hematuria was associated with nondiabetic renal disease.

RESULTS

In the total cohort, hematuria was observed in 15.0% of the patients and was associated with young age, a lower estimated glomerular filtration rate, proteinuria, high blood pressure and short diabetes duration. Hematuria was significantly associated with an increased risk (hazard ratio 1.39, 95% CI: 1.10-1.76, P < 0.001) of end-stage renal disease, particularly in patients with CKD stages 1-3 or a urine protein-to-creatinine ratio of <1,500mg/g (P for interaction < 0.05). The odds ratio of hematuria for rapid renal progression was 1.81 (95% CI: 1.29-2.53, P < 0.001).

CONCLUSIONS

Hematuria is associated with nondiabetic renal disease in biopsied patients with diabetic CKD and is associated with an increased risk of end-stage renal disease in patients with early diabetic CKD.

Characteristics and comparison between diabetes mellitus and non-diabetes mellitus among chronic kidney disease patients: A cross-sectional study of the Chinese Cohort Study of Chronic Kidney Disease (C-STRIDE)

Although the prevalence of chronic kidney disease (CKD) and diabetes mellitus (DM) is increasing globally, information on Chinese CKD patients with DM is lacking. A total of 3499 pre-dialysis CKD patients from across China were enrolled in the Chinese Cohort Study of Chronic Kidney Disease (C-STRIDE) between November 2011 and April 2016. We divided the C-STRIDE patients into CKD with DM and CKD without DM groups and compared their clinical, demographic, and laboratory data in this cross-sectional study. CKD patients with DM were older, had a higher male-to-female ratio, and had more complications than CKD patients without DM. Age, smoking, and 24-h urinary protein levels were associated with co-occurrence of CKD and DM. Less than 50% of patients in either group took antilipemic, cardiovascular, cerebrovascular, or anti-anemic drugs. In addition, only 18.38% of CKD patients with DM had undergone a renal biopsy, and diabetic nephropathy was confirmed in 35.4% of them. Our findings suggest that several types of medication and renal biopsies should be used more frequently in the treatment of Chinese CKD patients with DM.

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 Retinopathy and Clinical Parameters Favoring the Presence of Diabetic Nephropathy could Predict Renal Outcome in Patients with Diabetic Kidney Disease

Diabetes duration, diabetic retinopathy (DR), and a diagnostic model have been proposed as clinical parameters favoring the presence of diabetic nephropathy (DN) in biopsied patients with diabetic kidney disease. DN, compared with non-diabetic renal disease, had poorer renal outcomes. We tested whether these clinical parameters favoring DN are associated with poorer renal outcomes in non-biopsied patients. In this study, 1330 patients with type 2 diabetes and chronic kidney disease stages 1-4 were included and divided according to diabetes mellitus (DM) duration >8 years, DR, or a diagnostic model for DN. These clinical parameters favoring DN were found in 62-77% of patients and associated with higher levels of proteinuria. In a Cox survival analysis, DR and the diagnostic model favoring DN were associated with an increased risk for end-stage renal disease with adjusted hazard ratios of 1.69 (95% CI: 1.16-2.45, P = 0.006) and 1.66 (95% CI: 1.05-2.61, P = 0.029), respectively. DR was associated with an increased risk for rapid renal disease progression. DM >8 years was not associated with renal outcome. Propensity score-matched analyses also showed similar results. In conclusion, DR and the diagnostic model favoring DN were associated with poorer renal outcomes.

The large spectrum of renal disease in diabetic patients

The prevalence of diabetic nephropathy (DN) among diabetic patients seems to be overestimated. Recent studies with renal biopsies show that the incidence of non-diabetic nephropathy (NDN) among diabetic patients is higher than expected. Renal impairment of diabetic patients is frequently attributed to DN without meeting the KDOQI criteria or performing renal biopsy to exclude NDN. In this editorial, we update the spectrum of renal disease in diabetic patients and the impact on diagnosis, prognosis and therapy.

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.

Clinicopathological characteristics of non-diabetic renal disease in patients with type 2 diabetes mellitus in a northeastern Chinese medical center: a retrospective analysis of 273 cases

OBJECTIVE

To investigate the clinical and histopathological features of non-diabetic renal disease (NDRD) superimposed on diabetic nephropathy (DN) in northeastern Chinese patients with type 2 diabetes mellitus (T2D), and compare the changes with those of pure DN and isolated NDRD.

METHODS

Single-center retrospective analysis based on medical records of 273 patients (172 men, mean age: 51.1 ± 12.4 years) with T2D who underwent renal biopsy between February 2000 and October 2015. All patients were diagnosed as cases of pure DN, isolated NDRD or NDRD superimposed on DN.

RESULTS

Out of the 273 T2D patients, 68 (24.9 %) had DN, 175 (64.1 %) had NDRD, and 30 (11.0 %) had NDRD superimposed on DN. Idiopathic membranous nephropathy (IMN, 29.7 %) was the most common NDRD followed by IgA nephropathy (IgAN, 22.9 %), and hypertensive renal arteriolar sclerosis was the most common lesion in patients diagnosed as NDRD superimposed on DN. Patients with NDRD had a shorter duration of diabetes and lower frequencies of diabetic retinopathy (DR, 6.9 %) and renal failure (28.0 %), which is consistent with higher estimated glomerular filtration rates (eGFR) and lower systolic blood pressure (SBP). No significant between-group differences were observed with respect to proteinuria and hematuria.

CONCLUSION

Renal biopsy is strongly recommended for T2D patients to distinguish DN, NDRD and NDRD superimposed on DN, especially in patients with no signs of DR. This approach may help in early diagnosis and treatment of NDRD and improve renal outcomes in northeastern Chinese T2D patients.

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.

A case of triple pathology: seronegative anti-glomerular basement membrane antibody-mediated glomerulonephritis and membranous nephropathy in a patient with underlying diabetic kidney disease

In diabetic patients with acute kidney injury (AKI), kidney biopsy often reveals non-diabetic kidney pathology. This case describes a patient with known Type 1 diabetes who presented with AKI, nephrotic syndrome and haematuria. Combination pathology of seronegative anti-glomerular basement membrane antibody-mediated glomerulonephritis (anti-GBM GN), membranous nephropathy (MN) and diabetic nephropathy (DN) was demonstrated. Strong linear GBM IgG-staining on biopsy with crescentic GN and clinical AKI led to a diagnosis of anti-GBM GN, although serum antibodies were not detectable. Features of DN, Kimmelstiel-Wilson nodules and albumin staining were also present, along with features of MN, such as subepithelial deposits on electron microscopy. Despite treatment with immunosuppression and plasmapheresis, there was no recovery of kidney function. Coexisting anti-GBM GN and MN is well recognized, but the concurrent diagnosis with DN has not been described.

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.

End-stage renal disease and survival in people with diabetes: a national database linkage study

BACKGROUND

Increasing prevalence of diabetes worldwide is projected to lead to an increase in patients with end-stage renal disease (ESRD) requiring renal replacement therapy (RRT).

AIM

To provide contemporary estimates of the prevalence of ESRD and requirement for RRT among people with diabetes in a nationwide study and to report associated survival.

METHODS

Data were extracted and linked from three national databases: Scottish Renal Registry, Scottish Care Initiative-Diabetes Collaboration and National Records of Scotland death data. Survival analyses were modelled with Cox regression.

RESULTS

Point prevalence of chronic kidney disease (CKD)5 in 2008 was 1.63% of 19 414 people with type 1 diabetes (T1DM) compared with 0.58% of 167 871 people with type 2 diabetes (T2DM) (odds ratio for DM type 0.97, P = 0.77, on adjustment for duration. Although 83% of those with T1DM and CKD5 and 61% of those with T2DM and CKD5 were receiving RRT, there was no difference when adjusted for age, sex and DM duration (odds ratio for DM type 0.83, P = 0.432). Diabetic nephropathy was the primary renal diagnosis in 91% of people with T1DM and 58% of people with T2DM on RRT. Median survival time from initiation of RRT was 3.84 years (95% CI 2.77, 4.62) in T1DM and 2.16 years (95% CI: 1.92, 2.38) in T2DM.

CONCLUSION

Considerable numbers of patients with diabetes continue to progress to CKD5 and RRT. Almost half of all RRT cases in T2DM are considered to be due to conditions other than diabetic nephropathy. Median survival time for people with diabetes from initiation of RRT remains poor. These prevalence data are important for future resource planning.

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.

Defining the spectrum of immunoglobulin A-dominant/codominant glomerular deposition in diabetic nephropathy

In patients with diabetic nephropathy (DN), the spectrum of immunoglobulin A (IgA)-dominant/codominant glomerular deposition (IgAGD) has not been addressed in the literature. The aim of our study is to detail the clinicopathological and outcome findings in patients with DN and IgAGD. Our database was retrospectively searched over a 10-year period for patients with DN and IgAGD. A total of 132 patients were included in the study, 55 with outcome data. All cases were reviewed by light microscopy, immunofluorescence, and electron microscopy. Mean age was 59 ± 13 years, with a 2:1 male-to-female ratio. Indications for biopsy were often multiple, with proteinuria/nephrotic syndrome and acute renal failure being the most common. All patients showed IgAGD and mesangial deposits by electron microscopy. Seventy-three (55.3%) patients had no proliferative glomerular changes and no clinical history of infection and were most consistent with IgA nephropathy on DN, whereas 19 (14.4%) showed proliferative glomerular changes, had a history of infection, and were most consistent with IgA-dominant infection-associated glomerulonephritis. Forty (30.3%) patients showed a mixture of these findings and did not fit into either category. Patients with a mean of 42 (2-120 range) months of follow-up showed an overall poor prognosis, with 59% of all respondents proceeding to renal replacement therapy or death (RRT/D) over an average of 23 (range, 4-54) months. Progression to RRT/D was most frequent in those most consistent with IgA-dominant infection-associated glomerulonephritis (71%), and by multivariate analysis, only advanced Tervaert morphologic classification (classes III and IV) was associated with progression to RRT/D.

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.

Clinical challenges in diagnosis and management of diabetic kidney disease

Diabetic kidney disease (DKD) is a major and increasing worldwide public health issue. There is a great need for implementing treatments that either prevent or significantly slow the progression of DKD. Although there have been significant improvements in management, the increasing numbers of patients with DKD illustrate that current management is not wholly adequate. The reasons for suboptimal management include the lack of early diagnosis, lack of aggressive interventions, and lack of understanding about which interventions are most successful. There are a number of challenges and controversies regarding the current management of patients with DKD. Understanding of these issues is needed in order to provide the best care to patients with DKD. This article describes some of the clinically important challenges associated with DKD: the current epidemiology and cost burden and the role of biopsy in the diagnosis of DKD. Treatment controversies regarding current pharmacologic and nonpharmacologic approaches are reviewed and recommendations based on the published literature are made.

Nondiabetic kidney diseases in type 2 diabetic patients

Background

The aim of this study was to evaluate the clinical characteristics of nondiabetic nephropathy in type 2 diabetes mellitus patients and to find a clinical significance of renal biopsy and immunosuppressive treatment in such a patient.

Methods

Renal biopsy results, clinical parameters, and renal outcomes were analyzed in 75 diabetic patients who underwent kidney biopsy at Chungnam National University Hospital from January 1994 to December 2010.

Results

The three most common reasons for renal biopsy were nephrotic range proteinuria (44%), proteinuria without diabetic retinopathy (20%), and unexplained decline in renal function (20.0%). Ten patients (13.3%) had only diabetic nephropathy (Group I); 11 patients (14.7%) had diabetic nephropathy with superimposed nondiabetic nephropathy (Group II); and 54 patients (72%) had only nondiabetic nephropathy (Group III). Membranous nephropathy (23.1%), IgA nephropathy (21.5%), and acute tubulointerstitial nephritis (15.4%) were the three most common nondiabetic nephropathies. Group III had shorter duration of diabetes and lesser diabetic retinopathy than Groups I and II (P=0.008). Group II had the lowest baseline estimated glomerular filtration rate (P=0.002), with the greatest proportion of renal deterioration during follow-up (median 38.0 months, P<0.0001). The patients who were treated with intensive method showed better renal outcomes (odds ratio 4.931; P=0.01). Absence of diabetic retinopathy was associated with favorable renal outcome in intensive treatment group (odds ratio 0.114; P=0.032).

Conclusion

Renal biopsy should be recommended for type 2 diabetic patients with atypical nephropathy because a considerable number of these patients may have nondiabetic nephropathies. And intensive treatment including corticosteroid or immunosuppressants could be recommended for type 2 diabetic patients with nondiabetic nephropathy, especially if the patients do not have diabetic retinopathy.

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.

Nondiabetic kidney disease in type 2 diabetic patients: A single center experience

Nondiabetic renal disease (NDRD) is seen as a cause of proteinuria and renal failure in type 2 diabetes mellitus (DM). The clinical differences between NDRD and diabetic glomerulosclerosis (DGS) are not clear. This study was done to find the spectrum of NDRD in type 2 DM patients and differences in clinical profile between NDRD and DGS patients. Data of patients with type 2 DM who underwent renal biopsy in this institute from 1990 to 2008 were analyzed retrospectively. Patients were categorized as isolated NDRD, NDRD with DGS, and isolated DGS. A total of 75 patients were included. Mean age was 45 ± 10.2 years, male to female ratio was 3.1 : 1, median duration of DM was 12 months (range, 1 year-15 years), proteinuria was 4.2 ± 3.4 g/day, and serum creatinine was 4.3 ± 3.9 mg/dl. Hypertension was observed in 63 (84%) cases and microscopic hematuria in 24 (32%) cases. Nephrotic syndrome (38.7%) was the commonest clinical presentation. Forty-eight (64%) cases had NDRD and 27 (36%) had DGS. The commonest NDRD was minimal change disease (12.5%). Three (6.3%) patients had lupus nephritis. Tubulointerstitial nephritis has been observed in 10.4% patients. No significant differences between NDRD and DGS patients were found except hypertension which was significantly high in the DGS group. Acute kidney injury and nephritic syndrome were not observed in the DGS group. In conclusion, the incidence of biopsy-proven NDRD in type 2 DM in this study was high. Kidney biopsy aided in the detection of NDRD in clinically suspected patients.

Prevalence of haematuria positively associated with urine albumin excretion in Type 2 diabetes

AIMS

Some guidelines or studies consider haematuria an indication for renal biopsy or a potential cause of albuminuria that precludes accurate assessment of urinary albumin excretion. This study examined the justification of excluding haematuria in interpreting urinary albumin excretion in patients with Type 2 diabetes and its associations with other diabetes-related variables.

METHODS

Between May and November 2008, patients with Type 2 diabetes at a single centre with data on urinary albumin excretion and urinalysis in the same urine sample were recruited. Urinary albumin excretion was determined by urine albumin/creatinine ratio in spot urine. Diagnosis of haematuria was made by positive urine occult blood from 1+ to 4+ and/or presence of more than nine red blood cells/ml in urinalysis. Demographic, anthropometric, clinical and laboratory variables and diabetes-associated complications were analysed.

RESULTS

In total, 743 patients were enrolled. Prevalence of haematuria among patients with normoalbuminuria, microalbuminuria, or macroalbuminuria was 8.7% (n = 13), 16.1% (n = 67) and 35.8% (n = 64), respectively. Urine albumin/creatinine ratio was significantly higher, while macroalbuminuria was more common in patients with haematuria (n = 144) than in those without (n = 599). Multiple regression analysis identified urine albumin/creatinine ratio (odds ratio 1.33, P = 0.01) and macroalbuminuria (odds ratio 2.66, P = 0.01) as the only independent predictors of haematuria. Moreover, urine albumin/creatinine ratio was an independent predictor of haematuria in the macroalbuminuria subgroup (odds ratio 1.30, P = 0.04).

CONCLUSIONS

Increased urine albumin/creatinine ratio and macroalbuminuria were the only independent predictors of haematuria in patients with Type 2 diabetes, raising questions on the justifications of excluding haematuria in interpreting urinary albumin excretion in patients with Type 2 diabetes and including haematuria as an indication for renal biopsy in those with macroalbuminuria.

Clinical predictors of non-diabetic renal disease and role of renal biopsy in diabetic patients with renal involvement: a single centre review

BACKGROUND

Type 2 diabetes mellitus (T2DM) is reportedly the leading cause of end-stage renal disease (ESRD) worldwide. However, non-diabetic renal diseases (NDRD) are not uncommon among T2DM patients with renal involvement. Our study aimed to examine the prevalence of NDRD in T2DM and clinical markers for diabetic nephropathy (DN) and NDRD and to determine the role of renal biopsy in T2DM patients and its impact on clinical practice.

METHODS

We conducted a retrospective analysis of T2DM patients in whom renal biopsies were performed from January 2004 to March 2008 (n = 110).

RESULTS

Biopsy results were divided into three groups: group I/pure DN (62.7%), group II/isolated NDRD (18.2%), and group III/mixed lesions (19.1%). The causes of NDRD in decreasing order of frequency were acute interstitial nephritis, glomerulonephritides, hypertensive renal disease, and acute tubular necrosis. Significant clinical markers for DN are presence of diabetic retinopathy and longer duration of diabetes. For NDRD, useful clinical markers include the presence of acute renal failure and microscopic hematuria. In the DN subgroup, Indians had significantly shorter duration of diabetes on biopsy compared with Malays and Chinese.

CONCLUSIONS

NDRD is prevalent in T2DM patients, and given its potentially treatable nature, renal biopsy should be considered in T2DM patients with nephropathy, especially in those with atypical features.

Factors associated with diabetic nephropathy in subjects with proliferative retinopathy

AIM

The purpose was to compare the phenotype of subjects with type 2 diabetes mellitus having both retinopathy and nephropathy with that of subjects having retinopathy but no nephropathy.

METHODS

We recruited 196 subjects; 85 were normoalbuminuric (controls), whilst cases consisted of patients with micro- (n = 66) or macroalbuminuria (n = 45). Both groups underwent 24-h blood pressure (BP) monitoring and were analysed regarding markers of the metabolic syndrome, inflammation (erythrocyte sedimentation rate [ESR] and high-sensitivity CRP [hsCRP]) and insulin resistance (HOMA-IR).

RESULTS

Cases had significantly higher white cell count (P = 0.02), ESR (P < 0.001), platelets (P = 0.02), triglycerides (P = 0.001), uric acid (P < 0.001), daytime and night-time systolic BP (P = 0.001 & P = 0.001, respectively), diastolic BP (P = 0.007 & P = 0.001), pulse pressure (P = 0.02 & 0.055) and mean arterial pressure (P = 0.001 & P < 0.001) in univariate analysis. Cases had a lower haemoglobin level (P = 0.01) and estimated glomerular filtration rate (eGFR) (P = 0.002) in comparison with controls. Multivariate analysis showed that night-time diastolic BP (P = 0.002, B = 1.057), platelet count (P = 0.018, B = 1.007) and eGFR (P < 0.001, B = 0.097) are independent predictors of diabetic nephropathy. Platelet count (P = 0.045, B = 1.006), night-time mean diastolic BP (P = 0.029, B = 1.042) and eGFR (P = 0.001, B = 0.975) were also found to be independent predictors of the occurrence of microalbuminuria.

CONCLUSIONS

By analysing factors associated with diabetic nephropathy rather than microvascular disease in general, this study provides evidence that night-time diastolic BP and a relative increase in platelet count are associated with incipient diabetic nephropathy.