Diabetes mellitus is one of the most challenging health problems in the 21st century. Type 2 diabetes consists of 85-95% of all diabetes mellitus cases in developed countries. It is estimated that approximately 285 million people worldwide in the age group 20-79 years had diabetes mellitus in 2010. If preventive measures are not taken, this number is expected to increase to 438 million by 2030.1 

Diabetes mellitus metabolic disorder is characterized by chronic hyperglycaemia (high blood glucose levels) resulting from insulin resistance and impaired insulin secretion. It accounts for the majority of diabetes cases globally, with its prevalence rising at an alarming rate due to lifestyle factors such as poor diet, physical inactivity, and obesity. Unlike type 1 diabetes, which is primarily caused by an autoimmune attack on insulin-producing cells, type 2 diabetes develops when the body cannot effectively use insulin (insulin resistance) or fails to produce enough insulin to meet its needs.2

Diabetic nephropathy (DN) is a serious and common complication of diabetes mellitus (DM), characterized by progressive damage to the kidneys due to long-term high blood glucose levels. It is the leading cause of end-stage renal disease (ESRD) worldwide, contributing significantly to the global burden of kidney disease. In India, nearly 30% of chronic renal failure cases are attributed to diabetic nephropathy, underscoring the magnitude of the problem in the country.

The pathophysiology of diabetic nephropathy involves a combination of factors, including hyperglycemia, increased blood pressure, and the effects of advanced glycation end-products (AGEs), which lead to damage to the blood vessels in the kidneys. This damage impairs the kidneys' ability to filter waste and excess fluids from the blood effectively. Over time, the kidneys' filtering units (nephrons) become scarred, resulting in proteinuria (the presence of excess protein in the urine), a key marker of diabetic nephropathy.3

Risk factors for the development and progression of diabetic nephropathy include poor blood glucose control, hypertension, genetics, smoking, and long duration of diabetes. Early detection through regular screening for albuminuria (protein in the urine) and monitoring of kidney function is critical in preventing the progression to ESRD.4

If left untreated, diabetic nephropathy can lead to kidney failure, necessitating dialysis or kidney transplantation. However, early intervention can slow the progression of the disease. Tight control of blood glucose levels, management of blood pressure (especially with renin-angiotensin-aldosterone system blockers such as ACE inhibitors or angiotensin receptor blockers), lifestyle modifications (such as a low-sodium, low-protein diet), and use of medications that target kidney protection are essential in managing diabetic nephropathy.4

The national diabetes data group and world health organization have issued diagnostic criteria for diabetes mellitus, Symptoms of diabetes plus random blood glucose concentration ≥ 11.1mmol/L (200 mg/dl) or Fasting plasma glucose ≥ 7.0 mmol/L ( 126 mg/dl) or Two hour post prandial glucose ≥ 11.1 mmol/L (200 mg/dl) .Patients with Type 2 diabetes mellitus often have a long asymptomatic period of hyperglycemia, and many have complications at the time of diagnosis. To determine the relationship between HbA1c levels and the presence of microalbuminuria in patients with type 2 diabetes.5

The study was conducted at B. J. Govt Medical College, Pune. We collected data from 50 diagnosed cases of type 2 diabetes mellitus and 50 age and sex matched healthy individuals the outpatient Department of Medicine. The cases were selected based on the simple random sampling method. The study protocol was approved by the institutional ethical committee, and informed consent was obtained from the subjects under study. The study was done from January 2024 to June 2024. The study design is an Observational cross-sectional study.

Inclusion criteria: The Following people were included in the study.

Cases:

1. Patient with age group of 30 -80 years.
2. Diagnosed cases with fasting blood sugar > 126 mg/dl (7.0 mmol/l).
3. Fasting is defined as no caloric intake for at least 8 hours.
4. Patient with 2 hours post prandial glucose > 200 mg/dl (11.1 mmol/l ).

Controls

Age and sex matched healthy individuals are taken as controls.

Exclusion criteria

Patients with type 1 diabetes mellitus congestive cardiac failure, urinary tract infections, nephritic syndrome, chronic glomerulonephritis, ketoacidosis, pregnancy, alcoholics

Sample collection

Sample collection was done from January 2024 to June 2024. Under aseptic precautions,  4 ml of fasting venous blood samples was taken from the study subjects, allowed to stand for 30 minutes and centrifuged for 10 minutes. The serum sample was used for the estimation of FBS, PPBS (GOD/PAP method), Creatinine (Jaffe’s method), and Urea (Enzymatic Kinetic method), a whole blood sample was used for the estimation of HbA1c (HPLC By Biorad D10). Early morning mid-stream urine sample (10 ml) in a sterile container without preservative was used for the estimation of urine microalbumin (Immunoturbidimetric method) were estimated by using Roche e411 autoanalyzer.

 Statistical methods

Chi-square and Fisher Exact test have been used to find the Significance of proportion of incidence of microalbuminuria with study parameters namely Age, Duration of DM, GHB %. The Odds ratio has been used to find the strength of the relationship between the incidence of microalbuminuria and other study parameters. Student t-test has been used to find the significance of mean levels of lab parameters between the presence and absence of microalbuminuria

Statistical software

The Statistical software SPSS 11.0 and Systat 8.0 were used for the analysis of the data and Microsoft Word and Excel have been used to generate graphs, tables etc.

Table 1 Comparison of Biochemical parameters between the two study groups

Table 2:  HbA1c and Microalbuminuria at different levels in the two study groups

Table 3: Mean pattern of parameters and their correlation in presence and absence of microalbuminuria in cases

Table 4: Pearson's correlation co-efficient (r)

Diabetes mellitus is a group of metabolic disorders of carbohydrate metabolism in which glucose is underutilized, producing hyperglycaemia. The diagnosis of diabetes mellitus solely depends on the demonstration of hyperglycaemia. In our study, the mean FBS values were 198.2±31.2 mg/dl and 89.12 ± 23.2 mg/dl in controls and cases, which is statistically highly significant (p<0.001). Our study also correlated FBS value in a diabetic patients with or without microalbuminuria and the study concluded that mean FBS value in a patients without microalbuminuria is 118 ± 14.3 and in patients with microalbuminuria is 189.5±23.5 which is statistically significant (p<0.001). Similarly, the mean PPBS values were 246 ± 39.2 mg/dl and 119.63 ± 19.2 mg/dl in controls and cases, which is statistically highly significant (p<0.001). Our study also correlated PPBS value in diabetic patients with or without microalbuminuria and the study concluded that mean PPBS value in patients without microalbuminuria is 246.3 ±17.5 and in a patients with microalbuminuria is 280 ± 16.25, which is statistically significant (p=0.01). Hyperglycaemia is a causative factor in the pathogenesis of diabetic nephropathy. Glucose reacts non-enzymatically with primary amines of proteins, forming glycated compounds. Hyperglycaemia exerts toxic effects and results in kidney damage by directly altering intercellular signalling pathways and via many biochemical pathways.⁶

Glycated hemoglobin

Glycated hemoglobin is effective in monitoring long-term glucose control in patients with diabetes mellitus⁷. The complication of diabetes depends not only on the duration of diabetes mellitus but also by the mean average level of chronic glycemia as measured by glycated hemoglobin level⁸.

In our study, the mean HbA1c values were 6.5±1.2% in controls and 7.89±2.0 % in cases, which is statistically highly significant (p<0.001). Our study also correlated HbA1c value in diabetic patients with or without microalbuminuria, and the study concluded that the mean HbA1c value in patients without microalbuminuria is 6.5 ±1.2  and in patients with microalbuminuria is 7.89 ± 2.0, which is statistically significant (p=0.001).

Microalbuminuria

In our study, the mean microalbuminuria values were 8.98±3.52 in controls and 46.21±34.2% in cases, which is statistically highly significant (p<0.001). Glomerular structural changes typical of diabetic nephropathy are established by the time microalbuminuria becomes apparent[115]. In the present study, a statistically significant positive correlation was found between the microalbuminuria and the FBS (r=0.30), PPBS (r=0.29) and duration of Diabetes mellitus (r=0.79) which was consistent with the findings reported in Varghese et al^19. There is no statistically significant correlation between microalbuminuria and urea and creatinine.

Type 2 diabetes mellitus (T2DM) is increasingly recognized not just as a metabolic disorder but also as a condition that significantly impacts the endothelium, the thin layer of cells that line blood vessels. Endothelial dysfunction in diabetes occurs in a generalized and widespread manner, affecting various vascular territories throughout the body. This dysfunction is particularly concerning because the endothelium plays a critical role in maintaining vascular tone, blood flow, and the balance of clotting factors8-10.

In Type 2 diabetes mellitus, prolonged hyperglycemia and other factors such as insulin resistance, increased oxidative stress, and inflammation contribute to endothelial injury, leading to impaired vascular function.8-12 Microalbuminuria serves as a warning for imminent nephropathy. Diabetic subjects with microalbuminuria not only experience ongoing progressive nephropathy, but are also at a significantly increased risk of developing other complications associated with endothelial dysfunction. Microalbuminuria serves as an early indicator of kidney damage in diabetes, but its presence also suggests widespread vascular involvement, affecting various organ systems.13-15

Even among randomly selected patients, an incidence of 38% for microalbuminuria is evident. Among various other studies, the prevalence of microalbuminuria ranges from 25% to 35%.14,16-18

In our study microalbuminuria tended to be more common in the cases as compared to control. There are many reasons for this phenomenon. Firstly, deterioration in the b -cell function is the likely factor to contribute to worsening glycemic control. Poor values of HbA1c are known to be associated with increasing incidence of microalbuminuria.18

Hyperglycemia plays a central role in the pathogenesis of diabetic nephropathy. Chronic high blood glucose levels contribute to various biochemical processes that lead to renal damage. One such process is the non-enzymatic glycation of proteins, which is a fundamental mechanism by which hyperglycemia leads to complications in diabetes, including nephropathy. Hyperglycemia exerts toxic effects on various tissues, including the kidneys, and plays a central role in the pathogenesis of diabetic nephropathy. It induces kidney damage through a variety of biochemical and cellular mechanisms, including direct alterations in intercellular signaling pathways, as well as through the accumulation of advanced glycation end-products (AGEs), increased oxidative stress, and inflammation.19

Glycated hemoglobin (HbA1c) is a crucial biomarker for monitoring long-term glucose control in patients with diabetes mellitus. It reflects the average blood glucose level over the past 2-3 months by measuring the percentage of haemoglobin that has become glycated (or attached to glucose). The higher the blood glucose level over time, the greater the percentage of hemoglobin that becomes glycated, making HbA1c an effective measure of chronic glycemia.20

Formation of HbA1c is essentially irreversible and the concentration in blood depends on both the life span the red blood cells (average 120 days) and glucose concentration. As the rate of formation of HbA1c is directly proportional to the concentration of glucose in blood, the HbA1c concentration represents the integrated values for glucose over the preceding 6-8 weeks.20

In patients with poorly controlled DM, values may extend to twice the upper limit of the reference interval or more but rarely exceed 15%. There is no specific value of HbA1c below which the risk of diabetic complications is eliminated completely. The ADA states that the goal of treatment should be maintain HbA1c <7% ADA recommends that HbA1c should be routinely monitored at least every 6 months in both type 1 and type 2 DM.20

Our study correlated HbA1c value in diabetic patients with or without microalbuminuria and the study concluded that mean HbA1c value in a patients without microalbuminuria statistically insignificant and in a patients with microalbuminuria is statistically significant. Although this is a cross sectional study, these findings raise concern regarding the strong association between poor glycemic control and microalbuminuria. Our study is in accordance with the study done by Naveen P21 et al. who showed a significant correlation between microalbuminuria and HbA1c. Idogun ES et al22 showed the mean HbA1c was the highest in diabetic with microalbuminuria when compared with diabetic without microalbuminuria. Shivananda nayak B and Geetha Bhaktha, also showed increased HbA1c levels in diabetic nephropathy patients and diabetic patients without any complications compared to healthy controls.23

Microalbuminuria predicts the development of overt diabetic nephropathy in type 1 and type 2 DM but the relationship is less clear in type 2 because of heterogenesity and presence of other risk factor for microalbuminuria in these elderly patients. Glomerular structural changes typical of diabetic nephropathy are established by the time microalbuminuria becomes apparent.25

In a study done by Melidonis A, Tournis S, it was shown that urinary albumin levels were higher in type 2 diabetic patients with signs of nephropathy compared to control group.26 the protein excretion increases in diabetic subjects compared to controls due to renal involvement caused by prolonged glycemia. This further increases with duration of diabetes. In the present study, statistically highly significant positive correlation was found between microalbuminuria and HbA1c which was similar to findings reported by Varghese et al,19 and the study conducted in Yazd. However, Huraib et al26 Shehnaz AS et al reported there was no statistically significant correlation between the microalbuminuria and HbA1c in diabetes mellitus patients.

The present study indicated that measuring glycosylated haemoglobin as an indicator of glycemic control and microalbuminuria in urine sample for kidney involvement in diabetic subjects provide a convenient method for early diagnosis. Thus the study suggests microalbuminuria as a nephropathy marker in diabetes mellitus.

1. Shonima V, Uma MI, Risk factor analysis and prevalence of microalbuminuria among type 2 diabetes mellitus subjects: The need for screening and monitoring microalbuminuria. Asian journal exp. Biological science, 2010:vol 1(3):652-659.
2. Perrin NE, Torbjornsdotter T, Jaremko CA, Berg UB. Risk markers of future microalbuminuria and hypertension based on clinical and morphological parameters in young type 1 diabetic patients. Pediatr Diabetes;2010(5):305–313.
3. Agarwal SK, Dash SC. Spectrum of renal diseases in Indian adults. J Aossc Physicians India. 2000;18(6):594–600. Powers AC. Diabetes mellitus . In: Jameson JL, editor. Harrison′s endocrinology. 1st ed. Newyork: McGraw-Hill ; 2006,. p. 303–304.
4. Sacks DB. Carbohydrates. In: Burtis CA, Ashwood ER, Burns DE, Tietz textbook of clinical chemistry. 4th edition. Philadelphia:W.B Saunders ; 2006,. p. 878–884.
5. Powers AC. Diabetes mellitus . In: Jameson JL, editor. Harrison′s endocrinology. 1st ed. Newyork: McGraw-Hill ; 2006,. p. 303–304.
6. Kahn CR, Weir GC, King GL, Jacobson AM, Moses AC, Smith RJ, editors. Joslin's Diabetes mellitus. 14th ed. South Asian: Lippincott Williams AND Wilkins 2010:796-808, 854-866.
7. Dornan TL, Carter RD, Bron AJ, Turner RC, Mann JI. Low density lipoprotein cholesterol: an association with the severity of diabetic retinopathy. Diabetologia. 1982;22:167–170.
8. Carl A, Burtis, Ashwood RE, editors. Tietz Clinical Chemistry and Molecular Diagnostics, Fourth Edition. W.B. Saunders Company ;2006,.
9. Burtis CA, ERA, WBSC, editors. Clinical Chemistry and Molecular Diagnostics ; 2006,. Fourth Edition.
10. Carl A, Burtis, Edward R, Ashwood, editors. Tietz Fundamentals of Clinical Chemistry, Fifth Edition ; 2001,.
11. Shono T, Okahara M, Ikeda I, Kimura K, Tamura H. -. J Electroanal Chem. 1982;132:99–105.
12. Burtis CA, Ashwood ER, Burns DE. Sacks DB. Carbohydrates. In: Tietz textbook of clinical chemistry ; 2006,. p. 886–888. 4th edition.
13. Reddy MV. Statistics for Mental Health Care Research, NIMHANS publication. Indi ; 2002.
14. Ghai R, Verma N, Goel A. Microalbuminuria in NIDDM and essential hypertension as a marker of severe disease. JAPI. 1994;42(10):771–774.
15. Patel KL, Mhetras SB, Varthakavi PK, Merchant PC, Nihalani KD. Microalbuminuria in non-insulin dependent diabetes mellitus. JAPI. 1999;47:596–601.
16. Taneja V, Sircar S, Kansra U, Lamba IMS. Microalbuminuria in normotensive non-insulin dependent diabetic subjects- associations and predictions. J Diab Assoc India. 1997;37(2):30–36
17. Jadhav UM, Kadam NN. Association of microalbuminuria with carotid Intima-Media thickness and coronary artery disease- A cross sectional study in Western India. JAPI. 2002;50:1124–1129.
18. Kahn CR, Weir GC, King GL, Jacobson AM, Moses AC, Smith RJ. Joslin’s Diabetes mellitus. 14th ed. South Asian: Lippincott Williams and Wilkins ; 2010,.
19. Varghese A, Deepa R, Rema M, Mohan V.Prevalence of microalbuminuria in type 2 diabetes mellitus at a diabetes center in southern India. Postgrad Med J. 2001;77:399–402.
20. Naveen P, Kannan N, Vamseedhar A, Bhanu PG, Aravind KR. Evaluation of glycated hemoglobin and microalbuminuria as early risk markers of nephropathy in Type 2 diabetes mellitus. Int J Biol Med Res. 2012;3(2):1724–1726.
21. Naveen P, Kannan N, Vamseedhar A, Bhanu PG, Aravind KR. Evaluation of glycated hemoglobin and microalbuminuria as early risk markers of nephropathy in Type 2 diabetes mellitus. Int J Biol Med Res. 2012;3(2):1724–1726.
22. Idogun ES, Kasia BE. Assessment of microalbuminuria and glycated hemoglobin in type 2 diabetes mellitus complications. Asian Pacific J Tropical Diseases. 2011;p. 203–205.
23. Rao GM. Serum electrolytes and osmolality in diabetes mellitus. Indian J Med Sci. 1992;(10):301–303.
24. Melidonis A, Tournis S, Hraklioti S. Serum sialic acid concentration and diabetic nephropathy in type 2 diabetes mellitus. Diabetologia Croatica. 1998;27(4).
25. Huraib S, Abu-Aisha H, Sulimani RA, Famuyiwa FO, Al-Wakeel J, Askar A. The pattern of diabetic nephropathy among Saudi patients with NIDDM. Ann Saudi MED. 1995;15:120–124.
26. Huraib S, Abu-Aisha H, Sulimani RA, Famuyiwa FO, AlWakeel J, Askar A,etal, The pattern of diabetic nephropathy among Saudi patients with NIDDM. Ann Saudi MED .1995;15:120-4