Background of the Study, Aims and Objectives : There are very few studies on histological patterns of diabetic nephropathy in our part of country. The aim of this study was to evaluate the renal involvement in patients with Type-2 diabetes mellitus (T2DM) , assess the histopathological changes and establish a clinico-pathological correlation. Subjects, Method and Materials : Thirty two Type 2 DM patients with nephropathy, after screening consecutive hundred(100) Type 2 Diabetics admitted to the Medicine Department were evaluated for renal involvement by kidney biopsy and histopathological study. Statistical analysis was done by student’s t-test, chi-square and linear regression analysis. Results: Thirty two patients (32) with diabetic nephropathy (20 males and 12 females) formed the study group out of hundred (100) consecutive Type-2 diabetes mellitus patients (58 males and 42 females) admi t ted to Medicine Department of SCB Medical College Hospital, Cuttack. The frequency of occurrence of clinical diabetic nephropathy was 32%. Most of the patients were having duration of DM of 6-10 years (87.5%). Pedal edema was found in 96.87%, hypertension in 87.5% patients respectively. Regression analysis showed that duration s of DM and HbA1c were the two significant risk factors (P < 0.05) for development of nephropathy. Histopathologically, diffuse glomerulosclerosis was the most common form of renal abnormality found in 93.75% followed by nodular glomerulosclerosis in 62.50% with overlap in many patients, membranous nephropathy in 12.5% and focal necrotising glomerulonephritis in 6.25% respectively. There was no statistically significant clinicopathological correlation observed between clinical and biochemical parameters in patients harbouring the two predominant histological types of nephropathy i.e. diffuse and nodular glomerulosclerosis with respect to age, sex, duration of diabetes, body mass index, systolic blood pressure, HbA1c, 24 hour urinary protein, creatinine clearance, serum urea, serum creatinine or lipid profile. Conclusion: Duration s of diabetes and HbA1c were found to be strongly associated with development of diabetic nephropathy. Diffuse glomerulosclerosis was the most common form of renal abnormality found in 93.75% followed by nodular glomerulosclerosis in 62.50% of patients.
The global burden of DM is enormous with an estimated 366 million people living with DM worldwide (2011) [
Diabetes related vascular complications can be broadly classified as Microvascular complications which affect retina (Diabetic retinopathy), kidney (Diabetic nephropathy) and the peripheral nerves (Diabetic neuropathy) or macrovascular complications which includes coronary artery disease, cerebrovascular disease and peripheral vascular disease. Premature morbidity and mortality in diabetes occurs due to these complications. Diabetic nephropathy is the leading cause of End Stage Renal Disease (ESRD) worldwide [
Early work for diabetic renal disease in India was done under the aegis of World Health Organisation (WHO) in 1975 to 1978. In this Multi National Study of Diabetic Vascular Disease (M.N.S.D.V.D) spanning fourteen countries with India as one of the centres (Delhi) observed DN in 9.3% males and 4.2% females with DM duration of 0 - 6 years, in 10.7% males and 5.7% females with DM duration of 6 to 13years and in 23% males and 13.6% females with DM duration of ≥14 years [
Significant albuminuria or serum creatinine >1.5 mg/dl.
Following the same method Indian Council of Medical Research (ICMR) conducted a study in nine centres in India in which SCB Medical College & Hospital, Cuttack was one of the centre. DN in this study was observed in 12.2% of males and 5.3% of females in the first group (DM duration of 0 - 6 years), in 18% males and 8.7% females in the second group (DM duration of 6 - 13 years) and in 22.5% males and 7.5% of females in the third group (DM duration ≥ 14
W.H.O.M.N.S.V.D. (1975-78) | ICMR (1986-89) | ||||||
---|---|---|---|---|---|---|---|
14 Countries | 9 Centres | ||||||
(Delhi Centre) | |||||||
Duration (Yrs) | 0-6 | 7 - 13 | ≥4 | Duration (yrs) | 0 - 6 | 7 - 13 | ≥14 |
M(n-289) | 9.3 | 10.7 | 23.0 | M (n = 262) | 12.2 | 18.0 | 22.5 |
F(n-266) | 4.2 | 5.7 | 13.6 | F (n = 245) | 5.3 | 8.7 | 7.5 |
Cause of Death | 1966 | 1976 | 1986 |
---|---|---|---|
n = 75 | N = 560 | n = 580 | |
DKA | 9.3 | 12.4 | 6.5 |
Total Vascular Disease | 76.0 | 69.0 | 74.5 |
Cardiac | 42.3 | 29.1 | 23.8 |
Cereberal | 11.0 | 11.7 | 10.5 |
Renal | 22.7 | 28.2 | 40.2 |
Cirrhosis | 6.7 | 3.2 | 3.3 |
Infections | 2.7 | 5.5 | 9.2 |
Others | 4.0 | 9.9 | 6.5 |
years) [
Pioneering epidemiological work done by Indian CKD Registry established under the aegis of Indian Society of Nephrology(ISN) had made pertinent observations that diabetes mellitus is the cause of CKD in 31.2% of patients [
Study in Cuttack showed that there was greater degree of insulin resistance and β cell dysfunction and atherosclerosis in diabetics than non-diabetics with chronic kidney disease [
The Chennai Urban Rural Epidemiological Study (CURE) revealed overt proteinuria in 2.2% and microalbuminuria in 26.9% of population [
Till date there are few studies regarding different types of nephropathy in patients of Type-2 Diabetes Mellitus. Hence the present study was conducted to evaluate renal involvement in patients of Type-2 diabetes mellitus.
This study was carried out to determine various renal histopathological lesions in Type-2 diabetis mellitus patients with renal dysfunction and to establish clinic- pathological correlation.
Hundred (100) Type-2 DM patients consecutively admitted to PG Department of Medicine of S.C.B. Medical College and Hospital, Cuttack were evaluated for presence of nephropathy. Out of hundred (100) consecutive Type-2 DM patients 32 cases were found to have nephropathy as per the inclusive criteria of macrolabuminuria (>300 mg/dl) and/or serum creatinine > 1.2 mg/dl [
All T2DM patients with nephropathy of both genders having age more than 30 year were included in the study while patients with Type 1 Diabetes, Gestational Diabetes, Secondary Diabetes, patients with HIV infection, patients on steroid therapy, patients on chronic use of nephrotoxic drugs, solitary kidney on ultrasound of abdomen and pelvis, deranged coagulation profile, thrombocytopenia, uncontrolled hypertension, urinary tract infection and obstructive uropathy were excluded from the study.
Detail clinical evaluation was done in all cases. Laboratory investigation like complete blood count (CBC), urine routine and microscopic, urine culture, fasting blood glucose, 2hr postprandial blood glucose, HbA1c, serum urea and creatinine, 24 hour urinary protein, serum sodium and potassium, liver function test, lipid profile, ECG and ultrasound of abdomen and pelvis were done after obtaining fully informed written consent.
Renal biopsy was done by nephrologist in the department of nephrology after recieving proper consent from the patients in S.C.B. Medical College Hospital, Cuttack. Kidney biopsy was performed with real-time ultrasound guidance and disposable automated biopsy needles. We used 18-gauge needles for greater tissue yield and fewer bleeding complications.
The tissue core was examined under light microscope to ensure that renal cortex had been obtained. A second pass of the needle was usually performed to obtain additional tissue where ever needed.
Histopathological study was done in Department of Pathology, S.C.B. Medical College, Cuttack. The renal tissue was placed in formalin and 3 μm thin, uniform cut sections were used for light microscopy. 10% aqueous formaldehyde buffer solution was used for fixation for light microscopy. The specimen was stained with hematoxylin and eosin (H&E), periodic acid-Schiff (PAS) and silver methenamine.
Diabetic nephropathy has been classified into 4 stages based on biopsy studies which are:
The data were analyzed using SPSS version 18. For continuous variables, data were presented as the mean ± standard deviation or the median with range, and the means were compared using one-way analysis of variance. For categorical variables, the data were presented as counts and percentages, and the differences were analyzed using the Chi-square test.
Thirty two patients (32) with diabetic nephropathy (20 males and 12 females) formed the study group out of hundred (100) Type-2 diabetes mellitus patients (58 males and 42 females) screened. Thus, the frequency of occurrence of clinical diabetic nephropathy was 32%. Majority of patients were from the age group of 50 - 60 years (56.25%).Most of the patients were having duration of diabetes of 6 - 10 years (87.5%). Positive family history of diabetes was present in 37.5% of patients (35% among males and 41.66% among females).Most cases of DN (Diabetic Nephropathy) presented with pedal edema as evidenced by 31 (96.87%) of patients including 19 (59.37%) males and 12 (37.50%) females had this finding. The mean BMI in the study group was 23.96 ± 1.93. Hypertension was present among 28 (87.50%) of patients including 19 (59.37%) males and 9 (28.12%) females. The mean SBP in our study group was 155 ± 10.31 mmHg and the mean diastolic blood pressure (DBP) was 88.25 ± 6.88 mmHg. The mean GFR and HbA1c in our study population were 41.64 ± 19.78 mL/min and 8.53 ± 1.18 respectively.
Among risk factors hypertension was present in 87.5%, dyslipidemia in 78.125% and smoking history in 43.75% of cases respectively.
Results of multiple linear regression analysis showed that duration of diabetes and HbA1C levels are strongly associated with development of nephropathy (p value < 0.05 for each) in diabetes.
Histopathological findings: Out of thirty two diabetic nephropathy patients, sixteen cases gave consent for renal biopsy. The histopathological findings were summarised in
a) Glomerular Obsolescence (global sclerosis): 12(75%) of the patients had biopsy specimen with varying degrees of glomerular obsolescence (global sclerosis).
Histopathological lesion | No of cases (16) | Total (100%) |
---|---|---|
Global sclerosis | 12 | 75% |
Diffuse glomerulosclerosis | 15 | 93.75% |
Nodular glomerulosclerosis | 10 | 62.5% |
Membranous glomerulopathy | 3 | 18.75% |
Focal necrotising glomerulonephritis | 1 | 6.25% |
Tubular atrophy | 14 | 87.5% |
Vacuolation | 10 | 62.5% |
Casts | 15 | 93.75% |
Interstitial fibrosis | 14 | 87.5% |
Hyaline change | 14 | 87.5% |
Intimal thickening | 12 | 75.00% |
b) Diffuse glomerulosclerosis (DGS): Diffuse glomerulosclerosis was the most common form of glomerular lesion seen. It was present in 15 (93.75%) patients (13 males and 2 females).
c) Nodular glomerulosclerosis (NGS): Nodular glomerulosclerosis was seen in 10 (62.50%) patients (8 males and 2 females).
d) Non diabetic nephropathy was found in 3 biopsy (18.75%) of which 2 (12.5%) were membranous glomerulopathy (MGN) with evidence of segmental tuft sclerosis in 9/35 (25.70%) of the sampled glomeruli in one patient and 1/9 (11.11%) in another patient; and 1 (6.25%) was focal necrotising glomerulonephritis, with partial fibrocellular crescents over 4/26 (15.30%) glomeruli.
Tubules showed focally prominent cytoplasmic vacuolar change. 10 biopsies (62.50%) showed tubular vacuolaton. 14 (87.50%) cases showed tubular atrophy with varying severity. Varying degrees of hyaline and granular casts were observed in tubules. Casts were present in 15 (93.75%) of cases.
14 (87.50%) patients had interstitial fibrosis of varying severity with interstitial inflammation.
Arterioles showed intimal thickening in 12 (75%) cases and hyalinosis in 14 (87.50%) of patients.
The difference in the clinical manifestations between between Diffuse Glomerulosclerosis and Nodular Glomerulosclerosis is presented in
As presented in
Diffuse glomerulosclerosis | Nodular glomerulosclerosis | p-value | |
---|---|---|---|
No of cases | 15 | 10 | |
Age(years) | 59.4 ± 8.67 | 59.6 ± 9.33 | 0.9567 |
Sex(M/f) | 13/2 | 8/2 | 1.000 |
Duration of diabetes (years) | 9.4 ± 1.95 | 9.7 ± 2.26 | 0.7267 |
BMI(kg/m2) | 24.26 ± 2.60 | 23.73 ± 2.39 | 0.6113 |
SBP(mm/Hg) | 158.4 ± 7.79 | 159.80 ± 8.61 | 0.6767 |
DBP(mmHg) | 87.33 ± 5.27 | 87.00 ± 6.34 | 0.8887 |
Diffuse glomerulosclerosis | Nodular glomerulosclerosis | p-value | |
---|---|---|---|
HBA1c | 9.08 ± 1.18 | 9.21 ± 1.19 | 0.7904 |
Creatinine clearance (ml/min) | 34.83 ± 17.45 | 35.649 ± 19.81 | 0.9142 |
Serum urea | 81.46 ± 42.42 | 81.70 ± 51.44 | 0.989 |
Creatinine (mg/dl) | 2.56 ± 1.004 | 2.64 ± 1.173 | 0.8567 |
24 hour urinary protein (mg/day) | 1504 ± 470.81 | 1586 ± 545.20 | 0.692 |
Serum triglycerides | 145.00 ± 36.05 | 143.80 ± 29.08 | 0.931 |
Total cholesterol | 205.53 ± 68.16 | 219.70 ± 60.28 | 0.599 |
LDL cholesterol | 93.00 ± 20.18 | 95.30 ± 23.07 | 0.794 |
HDL cholesterol | 45.86 ± 10.23 | 44.50 ± 11.28 | 0.757 |
groups. Serum cholesterol levels were higher but mean value of LDLc was below 100 mg/dl where as HDLc levels were above 40 mg/dl in both the groups.
Diabetes mellitus is the commonest metabolic disorder and has a high prevalence in India [
Till date, scanty studies have been conducted regarding the type of nephropathy in T2DM in this part of India, hence this study was conducted to evaluate nephropathy with histopathological changes in T2DM patients.
We found the incidence of diabetic nephropathy to be 32% in hospitalised patients. It has been reported that among 4837 patients with chronic renal failure seen over a period of 10 years, the prevalence of diabetic nephropathy was 30.3% India [
Another study from Karnataka by Raja Reddy et al. [
The mean duration of diabetes was 8.25 ± 1.98 years in our study. Similar study by Rudberg et al., in a study of adolescents with a mean duration of disease of 10.9 years, found that the duration of disease was an important factor in the overall severity of glomerulopathy [
The duration of diabetes, HbA1c level, Systolic and diastolic blood pressure and serum creatinine values are higher in NGS compared to the DGS variety. But there was no statistically significant difference between clinical and biochemical parameters in patients with nodular glomerulosclerosis and diffuse glomerulosclerosis.
The mean duration of diabetes was below 10 yr where as the mean age of patients was below 60 yrs suggesting development of nephropathy occurring at much earlier age in the T2DM in India than described in western literature [
The cohurt under study and mean BMI below 25 suggested that obesity is not a deciding factor in T2DM suffering from nephropathy in our population.
Even though majority of patients are in chronic kidney disease stage 3 (CKD stage 3) as per Cr. Clearance the biochemical parameters were worse than expected. (mean Creatinine above 2.5 mg% and serum urea above 80 mg%). This is an observation which is different from that observed in standard literature. The dyslipidemia observed neither revealed low HDLc nor high triglyceride which is classically seen in Indian diabetes. The most important risk factor for development of nephropathy was duration of diabetes followed by hypertension and smoking. The CURES-45 reported that risk factors for overt diabetic nephropathy include HBA1C, duration of diabetes, and systolic blood pressure, while for microalbuminuria smoking and diastolic blood pressure were also risk factors [
Multiple linear regression analysis of various risk factors with diabetic nephropathy is presented in
Histopathologically, DGS was the most predominant form of renal abnormality found in 93.75% followed by NGS in 62.50%, membranous nephropathy in 12.5% and focal necrotising glomerulonephritis in 6.25% of cases respectively. Study by Olsen et al. on 33 biopsies showed that 4 (12.12%) had Non Diabetic Renal Diseases (NDRD) and remaining 29 (87.87%) patients had DGS (9 = 27.27%) and NGS (20 = 60.60%) [
M Sahay et al. reported 24.56% NDRD and 75.43% DN [
Variable | Regression coefficient β | P value | 95% Cl Of coefficient of β |
---|---|---|---|
Age | 0.151 | 0.326 | −12.199 - 34.625 |
Duration of DM | 0.611 | 0.013 | 39.409 - 288.190 |
SBP | −0.232 | 0.306 | −0,35.879 - 11.937 |
DBP | 0.017 | 0.901 | −20.760 - 23.391 |
FBS | −0.029 | 0.898 | −7.052 - 6.231 |
HbA1c | 0.656 | 0.026 | 39.824 - 548.531 |
Serum urea | −0.609 | 0.035 | −18.045 - 0.752 |
Serum creatinine | −0.270 | 0.926 | −190.965 - 174.681 |
GFR | 0.008 | 0.977 | −15.370 - 15.799 |
BMI | −0.281 | 0.070 | −161.289 - 6.999 |
CHOL | −0.052 | 0.728 | −3.366 - 2.400 |
TG | −0.183 | 0.353 | −7.721 - 2.910 |
HDL | 0.327 | 0.039 | 1.127 - 39.302 |
LDL | 0.140 | 0.432 | −8.077 - 18.023 |
VLDL | −0.293 | 0.088 | −40.086 - 3.067 |
and 21.7% respectively [
There was not much difference between the clinical and biochemical parameters between patient of DGS and NGS. Similar study by Schwartz et al. in 1998 observed little difference between the clinical and biochemical parameters in these two types of DN patients [
Nephopathy occurs at a much earlier age in T2DM patients in India and the duration of diabetes resulting in nephropathy is less as compared to the western population. The typically described high triglyceride and low HDLc in Indian diabetics were not found in our study.
We conclude that nephropathy in patients of T2DM mellitus is of two distinctive pattern of glomerular pathology i.e. DGS and NGS. There was little difference between clinical and biochemical parameters in the DGS and NGS groups with respect to age, hypertension, BMI, duration of diabetes, dyslipidemia and glycemic control as reflected by HbA1c levels. Also noteworthy in the findings of this study was the fact that glomerular lesions other than those associated with diabetes were found in only three (3) patients. Hence, coexisting non diabetic renal disease may be associated with diabetic nephropathy in only a few patients with T2DM. Studies evaluating renal Parenchymal changes in T2DM are limited. Larger studies undertaking Histopathological evaluation of T2DM with Nephropathy will throw more light on NDRD & DN.
Nayak, S., Tripathy, S.K., Das, S., Das, B.P. and Kar, C.R. (2017) Evaluation of Type of Nephropathy in Patients of Type-2 Diabetes Mellitus. Journal of Diabetes Mellitus, 7, 281-293. https://doi.org/10.4236/jdm.2017.74023