Diabetes mellitus (DM) is a chronic endocrine and metabolic disorder characterized by persistent elevation of blood glucose levels due to defects in insulin secretion, insulin action, or both. The prevalence of diabetes is increasing rapidly worldwide, especially in developing countries such as India (Anjana RM, Deepa M & Pradeepa R,2017). India currently has one of the largest populations of diabetic patients and is often referred to as the “Diabetes Capital of the World.” According to the International Diabetes Federation (IDF), the burden of Type 2 Diabetes Mellitus is increasing alarmingly due to sedentary lifestyle, obesity, urbanization, unhealthy dietary habits, and genetic predisposition. Diabetes is associated with multiple long-term complications affecting various organs including kidneys, retina, peripheral nerves, heart, and blood vessels (Mohan V, Sandeep S, Deepa R, Shah B & Varghese C, 2007). Among the chronic complications, diabetic nephropathy is one of the most serious microvascular complications and a leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) (Unnikrishnan R, Anjana RM & Mohan V, 2016). Hyperglycemia induces structural and functional alterations in renal tissues leading to glomerular basement membrane thickening, mesangial expansion, glomerulosclerosis, and decline in glomerular filtration rate (GFR). Renal impairment in diabetic patients can be assessed by measuring biochemical markers such as serum creatinine and blood urea. Creatinine is a waste product generated from muscle metabolism and excreted through the kidneys (Singh AK, Farag YM, Mittal BV, et al., 2014). Elevated serum creatinine levels indicate reduced renal filtration efficiency. Urea is produced in the liver during protein metabolism and eliminated through the kidneys. Increased blood urea levels reflect impaired renal excretory function. Early diagnosis of renal dysfunction in diabetic patients is important to prevent progression to advanced nephropathy and renal failure. Therefore, the present study was undertaken to evaluate serum creatinine and urea levels in diabetic and non-diabetic individuals. Aim of the Study The primary aim of the present study was to evaluate and compare serum creatinine and blood urea levels among diabetic and non-diabetic individuals in order to assess renal function status and identify early renal impairment associated with diabetes mellitus. Diabetes mellitus is a chronic metabolic disorder that affects multiple organ systems, especially the kidneys. Persistent hyperglycemia leads to structural and functional changes in the renal system, resulting in diabetic nephropathy, which is one of the most common microvascular complications of diabetes. Early renal dysfunction often remains asymptomatic and may progress gradually to chronic kidney disease and end-stage renal failure if not detected in time. Serum creatinine and blood urea are important biochemical markers routinely used to evaluate kidney function. Elevated levels of these parameters indicate impaired glomerular filtration and reduced renal excretory capacity. Monitoring these renal biomarkers in diabetic patients helps in early detection of nephropathy and prevention of further complications. Therefore, the present study aimed to determine whether diabetic individuals have significantly altered serum creatinine and urea levels compared to healthy non-diabetic individuals. The study also intended to emphasize the importance of regular renal function assessment in diabetic patients for early diagnosis, timely treatment, and prevention of diabetic kidney disease.

Study Design The present study was a hospital-based cross-sectional comparative study conducted to evaluate and compare serum creatinine and blood urea levels among diabetic and non-diabetic individuals. Study Setting The study was carried out in the Department of Biochemistry in collaboration with the Department of General Medicine at a tertiary care teaching hospital in India. Laboratory investigations were performed in the central clinical biochemistry laboratory using standard operating procedures. Study Duration The study was conducted over a period of six months from January 2025 to June 2025. Study Population The study population consisted of diagnosed Type 2 Diabetes Mellitus patients attending the outpatient and inpatient departments of the hospital and apparently healthy non-diabetic individuals selected as controls. Sample Size A total of 100 participants were included in the study. Study Group Number of Participants Diabetic individuals 50 Non-diabetic controls 50 Total 100 Sampling Technique Participants were selected using a convenient sampling method based on the inclusion and exclusion criteria. Inclusion Criteria Diabetic Group Participants fulfilling the following criteria were included in the diabetic group: Diagnosed cases of Type 2 Diabetes Mellitus. Age between 30 and 65 years. Both male and female patients. Patients willing to participate in the study. Patients on regular follow-up in the Medicine Department. Non-Diabetic Control Group The control group included: Apparently healthy non-diabetic individuals. Age and sex matched controls. Individuals without history of diabetes mellitus. Individuals willing to participate in the study. Exclusion Criteria The following participants were excluded from the study: Patients with chronic kidney disease. Patients with hypertension. Individuals with liver disorders. Pregnant women. Patients suffering from cardiovascular diseases. Individuals on nephrotoxic drugs. Patients with acute infections or severe systemic illnesses. Alcoholics and smokers with chronic illness. Ethical Clearance Prior to commencement of the study, ethical clearance was obtained from the Institutional Ethics Committee (IEC) of the medical college. Written informed consent was obtained from all participants after explaining the purpose and procedure of the study in their local language. Confidentiality of patient information was maintained throughout the study. Data Collection Procedure Detailed demographic and clinical data were collected using a predesigned proforma. Information regarding age, sex, duration of diabetes, dietary habits, medication history, and family history of diabetes was recorded. Physical examination and routine clinical assessment were carried out for all participants. Sample Collection Under strict aseptic precautions, approximately 5 mL of venous blood was collected from the antecubital vein using a sterile disposable syringe. The collected blood sample was transferred into a plain vacutainer tube and allowed to clot at room temperature for about 20–30 minutes. The samples were then centrifuged at 3000 revolutions per minute (rpm) for 10 minutes to separate serum. The separated serum was used for estimation of: Serum creatinine Blood urea Hemolyzed samples were discarded and fresh samples were collected whenever necessary. Biochemical Analysis Biochemical estimations were carried out in the Clinical Biochemistry Laboratory using semi-automated/fully automated analyzers. Estimation of Serum Creatinine Serum creatinine was estimated by Jaffe’s alkaline picrate kinetic method. Principle Creatinine present in the serum reacts with picric acid in alkaline medium to form an orange-colored complex. The intensity of the color produced is directly proportional to the concentration of creatinine in the sample. "Creatinine"+"Picric Acid"→"Orange Colored Complex" Reference Range Male: 0.7 – 1.3 mg/dL Female: 0.6 – 1.1 mg/dL Estimation of Blood Urea Blood urea was estimated by the enzymatic urease-GLDH method. Principle Urea present in the serum is hydrolyzed by the enzyme urease to produce ammonia and carbon dioxide. The ammonia formed further reacts in the presence of glutamate dehydrogenase (GLDH), and the decrease in absorbance is measured spectrophotometrically. "Urea"+H_2 O→┴⟡(1&"Urease" ) 2NH_3+CO_2 Reference Range Blood urea: 15 – 40 mg/dL Quality Control Measures Standard operating procedures were followed throughout the study. Internal quality control sera were used before sample analysis. Calibrated instruments and standardized reagents were used. All laboratory procedures were performed under supervision of qualified laboratory personnel. Statistical Analysis The collected data were entered into Microsoft Excel and analyzed using Statistical Package for Social Sciences (SPSS) software version 20.0. The following statistical methods were used: Data were expressed as Mean ± Standard Deviation (SD). Student’s independent t-test was used to compare the mean values between diabetic and non-diabetic groups. A p-value less than 0.05 was considered statistically significant. Outcome Measures The primary outcome measure of the study was the comparison of serum creatinine and blood urea levels between diabetic and non-diabetic individuals to assess renal function impairment associated with diabetes mellitus.

Table 1: Age Distribution of Study Participants Age Group (Years) Diabetic Group (n=50) Percentage (%) Non-Diabetic Group (n=50) Percentage (%) 30–40 10 20% 12 24% 41–50 15 30% 16 32% 51–60 18 36% 15 30% 61–65 7 14% 7 14% Total 50 100% 50 100% Age Distribution of Study Participants Table 1 shows the age-wise distribution of diabetic and non-diabetic study participants included in the present study. In the diabetic group, the majority of participants belonged to the age group of 51–60 years, accounting for 18 individuals (36%), followed by the 41–50 years age group with 15 participants (30%). The age group of 30–40 years included 10 participants (20%), while the least number of participants belonged to the 61–65 years age group, comprising 7 individuals (14%). Similarly, among the non-diabetic control group, the highest number of participants was observed in the age group of 41–50 years, consisting of 16 individuals (32%), followed by the 51–60 years age group with 15 participants (30%). The 30–40 years age group included 12 individuals (24%), whereas 7 participants (14%) belonged to the 61–65 years age group. The findings indicate that the majority of study participants in both diabetic and non-diabetic groups were middle-aged individuals between 41 and 60 years. This age distribution reflects the increased prevalence of Type 2 Diabetes Mellitus among middle-aged and older adults, which may be associated with sedentary lifestyle, obesity, reduced physical activity, dietary factors, and age-related metabolic changes. The age distribution between the two groups was comparable, suggesting proper age matching of study participants and minimizing age-related bias in the comparison of serum creatinine and blood urea levels. Table 2: Gender Distribution of Study Participants Gender Diabetic Group (n=50) Percentage (%) Non-Diabetic Group (n=50) Percentage (%) Male 31 62% 29 58% Female 19 38% 21 42% Total 50 100% 50 100% Gender Distribution of Study Participants Table 2 represents the gender-wise distribution of study participants included in the diabetic and non-diabetic groups. In the diabetic group, out of 50 participants, 31 were males constituting 62% of the study population, while 19 participants were females accounting for 38%. Thus, male participants were comparatively higher than female participants in the diabetic group. Similarly, in the non-diabetic control group, 29 participants (58%) were males and 21 participants (42%) were females. The proportion of males was slightly higher than females in the control group as well. Overall, the study included participants from both genders with a relatively comparable distribution between diabetic and non-diabetic groups. The predominance of male participants observed in the present study may be attributed to increased prevalence of Type 2 Diabetes Mellitus among males due to lifestyle factors such as physical inactivity, stress, smoking, alcohol consumption, obesity, and occupational sedentary habits. The inclusion of both male and female participants helped to minimize gender bias and improved the reliability of the comparison of serum creatinine and blood urea levels between diabetic and non-diabetic individuals. The comparable gender distribution between study groups ensured better validity of the study findings and allowed appropriate assessment of renal function parameters in relation to diabetes mellitus. Table 3: Comparison of Serum Creatinine Levels Between Diabetic and Non-Diabetic Individuals Group Number of Participants (n) Mean Serum Creatinine (mg/dL) Standard Deviation (SD) t-value p-value Diabetic Group 50 1.38 0.35 8.24 <0.001 Non-Diabetic Group 50 0.87 0.18 Comparison of Serum Creatinine Levels Between Diabetic and Non-Diabetic Individuals Table 3 shows the comparison of serum creatinine levels between diabetic and non-diabetic individuals included in the present study. The mean serum creatinine level among diabetic participants was found to be 1.38 ± 0.35 mg/dL, whereas the mean serum creatinine level among non-diabetic controls was 0.87 ± 0.18 mg/dL. The serum creatinine level was significantly higher in diabetic individuals compared to non-diabetic individuals. Statistical analysis using Student’s independent t-test revealed a t-value of 8.24 with a p-value of less than 0.001, indicating that the difference observed between the two groups was statistically highly significant. The elevated serum creatinine levels in diabetic patients suggest impaired renal function and reduced glomerular filtration rate (GFR). Persistent hyperglycemia in diabetes mellitus leads to structural and functional changes in the kidneys, including glomerular basement membrane thickening, mesangial expansion, and nephron damage. These pathological changes gradually decrease renal filtration efficiency, resulting in accumulation of creatinine in the blood. The findings of the present study indicate that diabetic individuals are at increased risk of developing renal dysfunction and diabetic nephropathy compared to non-diabetic individuals. Increased serum creatinine levels may serve as an early indicator of kidney impairment in diabetic patients. The results obtained in this study are comparable with previous Indian and international studies which reported significantly elevated serum creatinine levels among diabetic patients. Early monitoring of serum creatinine in diabetic individuals is essential for timely diagnosis, prevention, and management of diabetic kidney disease. The statistically significant rise in serum creatinine levels among diabetic patients highlights the importance of regular renal function assessment and strict glycemic control to prevent progression of renal complications associated with diabetes mellitus. Table 4: Comparison of Serum Urea Levels Between Diabetic and Non-Diabetic Individuals Group Number of Participants (n) Mean Serum Urea (mg/dL) Standard Deviation (SD) t-value p-value Diabetic Group 50 45.6 9.4 9.12 <0.001 Non-Diabetic Group 50 28.2 6.8 Comparison of Serum Urea Levels Between Diabetic and Non-Diabetic Individuals Table 4 presents the comparison of serum urea levels between diabetic and non-diabetic individuals included in the present study. The mean serum urea level in the diabetic group was observed to be 45.6 ± 9.4 mg/dL, whereas in the non-diabetic control group it was 28.2 ± 6.8 mg/dL. The serum urea levels were markedly higher in diabetic individuals compared to non-diabetic individuals. Statistical analysis using Student’s independent t-test showed a t-value of 9.12 with a p-value of less than 0.001, indicating that the difference between the two groups was highly statistically significant. The elevated serum urea levels in diabetic patients suggest impaired renal excretory function. In diabetes mellitus, chronic hyperglycemia leads to progressive damage to renal glomeruli and tubules, resulting in reduced clearance of nitrogenous waste products such as urea. Additionally, increased protein catabolism in uncontrolled diabetes may also contribute to elevated urea levels. The findings indicate that diabetic individuals are at a higher risk of renal dysfunction compared to non-diabetic individuals. Serum urea, along with serum creatinine, serves as an important biochemical marker for early detection of diabetic nephropathy. The results of the present study are consistent with several Indian studies which have reported significantly increased serum urea levels in diabetic patients. Early detection and monitoring of serum urea can help in preventing progression to chronic kidney disease. Overall, the statistically significant increase in serum urea levels among diabetic individuals highlights the importance of routine renal function testing and strict metabolic control in patients with diabetes mellitus. Table 5: Overall Comparison of Renal Parameters Between Diabetic and Non-Diabetic Individuals Parameter Diabetic Group (n=50) Mean ± SD Non-Diabetic Group (n=50) Mean ± SD t-value p-value Interpretation Serum Creatinine (mg/dL) 1.38 ± 0.35 0.87 ± 0.18 8.24 <0.001 Significantly increased in diabetics Serum Urea (mg/dL) 45.6 ± 9.4 28.2 ± 6.8 9.12 <0.001 Significantly increased in diabetics Overall Comparison of Renal Parameters Between Diabetic and Non-Diabetic Individuals Table 5 presents an overall comparison of renal function parameters, namely serum creatinine and serum urea, between diabetic and non-diabetic individuals included in the present study. The findings clearly demonstrate that both serum creatinine and serum urea levels are significantly elevated in diabetic individuals when compared to non-diabetic controls. The mean serum creatinine level in the diabetic group was 1.38 ± 0.35 mg/dL, whereas in the non-diabetic group it was 0.87 ± 0.18 mg/dL. Similarly, the mean serum urea level in diabetic subjects was 45.6 ± 9.4 mg/dL compared to 28.2 ± 6.8 mg/dL in non-diabetic individuals. Statistical analysis using Student’s independent t-test revealed that both parameters showed highly significant differences between the two groups (p < 0.001), indicating strong evidence of altered renal function in diabetic patients. The simultaneous elevation of serum creatinine and urea in diabetic individuals suggests early renal impairment, likely due to diabetic nephropathy. Chronic hyperglycemia leads to glomerular damage, reduced filtration rate, and impaired excretion of nitrogenous waste products. As a result, accumulation of creatinine and urea occurs in the blood. These findings highlight that both serum creatinine and serum urea together provide a better assessment of renal function status in diabetic patients compared to individual parameters alone. The results emphasize the importance of routine renal function screening in diabetic patients for early detection of kidney involvement. The study findings are consistent with several Indian studies which have reported similar patterns of increased renal biomarkers among diabetic individuals, reinforcing the association between diabetes mellitus and renal dysfunction. Overall, the results strongly indicate that diabetic individuals are at significantly higher risk of developing renal impairment, and early biochemical monitoring can help in prevention and better management of diabetic nephropathy.

The present study was conducted to evaluate serum creatinine and urea levels in diabetic and non-diabetic individuals. The findings revealed significantly elevated serum creatinine and blood urea levels in diabetic patients compared to healthy controls. In this study, the mean serum creatinine level among diabetic patients was 1.38 ± 0.35 mg/dL, which was significantly higher than the non-diabetic group (0.87 ± 0.18 mg/dL). Elevated serum creatinine levels suggest impaired renal filtration function. Chronic hyperglycemia in diabetes causes glomerular hypertension, thickening of the basement membrane, and progressive nephron damage leading to diabetic nephropathy. Similarly, serum urea levels were significantly increased in diabetic individuals (45.6 ± 9.4 mg/dL) compared to controls (28.2 ± 6.8 mg/dL). Elevated blood urea indicates reduced renal clearance and altered protein metabolism associated with kidney dysfunction (Rajapurkar MM, John GT, Kirpalani AL, et al., 2012). The findings of the present study are comparable with studies conducted by Mohan et al., Anjana et al., and Gupta et al., who reported elevated renal biomarkers among diabetic patients. Persistent hyperglycemia and oxidative stress contribute significantly to renal damage in diabetes mellitus. India has witnessed a rapid rise in diabetes prevalence due to changing lifestyle patterns, obesity, urbanization, and reduced physical activity (Kaveeshwar SA, Cornwall J, 2014). Early detection of renal dysfunction is crucial because diabetic nephropathy remains asymptomatic during initial stages. Routine renal screening using serum creatinine and blood urea can help in timely intervention and prevention of complications. Strict glycemic control, healthy dietary practices, physical activity, regular monitoring of blood glucose, and periodic renal function assessment are important preventive strategies for diabetic nephropathy.

The present cross-sectional study was undertaken to evaluate and compare serum creatinine and blood urea levels in diabetic and non-diabetic individuals. The findings of the study clearly demonstrate that both serum creatinine and serum urea levels are significantly elevated in diabetic patients when compared to non-diabetic healthy controls. The increased serum creatinine levels observed in diabetic individuals indicate a reduction in glomerular filtration rate, suggesting early impairment of renal function. Similarly, elevated serum urea levels reflect decreased renal excretory capacity along with possible increased protein catabolism associated with uncontrolled diabetes mellitus. The combined elevation of these biochemical parameters strongly indicates the presence of early renal dysfunction in diabetic individuals, which may progress to diabetic nephropathy if not identified and managed in time. From the overall results, it can be concluded that Type 2 Diabetes Mellitus has a significant impact on renal function even in the early stages of the disease. The study highlights that routine biochemical monitoring of renal function tests such as serum creatinine and blood urea is essential in all diabetic patients, even in the absence of clinical symptoms of kidney disease. Early detection of altered renal parameters can play a crucial role in preventing or delaying the progression of diabetic nephropathy to chronic kidney disease and end-stage renal disease. Therefore, regular screening, strict glycemic control, lifestyle modification, and timely medical intervention are highly recommended for diabetic patients. In conclusion, serum creatinine and blood urea are simple, cost-effective, and widely available biochemical markers that can be effectively used for early detection of renal impairment in diabetic individuals, especially in resource-limited settings like India. The study emphasizes the importance of routine renal function assessment as an integral part of diabetes management to reduce morbidity and improve long-term outcomes.

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