Hospital based study on prevalence and risk factors for microalbuminuria in type 2 diabetes mellitus patients attending medical college and hospital

 

 

Abstract               Diabetes is major public health problem leading to different complications. Diabetic nephropathy initially presents as microalbuminuria and its management may slow the progress of the disease. The present hospital based cross sectional study was conducted to find the prevalence of microalbuminuria in type-2 diabetic patients and to evaluate the relation between microalbuminuria and other risk factors. The study enrolled 187 patients. Clinical history was taken and laboratory examination was done. It was found that the prevalence of microalbuminuria was 21.9%. Microalbuminuria is strongly associated with fasting blood sugar, glycosylated haemoglobin and duration of diabetes.

Key Word: Hospital Based Study, Microalbuminuria, Prevalence, Risk Factors, Type 2 Diabetes Mellitus

 

 

 

INTRODUCTION

As per recent estimates, there are about 346 million diabetics worldwide. Diabetes is predicted to become seventh leading cause of death by the year 2030¹. Prevalence of diabetes is expected to increase to 5.4% in the year 2025 as compared to prevalence of 4% reported in the year 1995². The expected increase in prevalence of diabetes in developed countries is 42% while for the developing countries; it is 70%³. Hence, diabetes and its complications are going to become major challenge in developing countries. The complications of diabetes mellitus result from macrovascular changes in the form of coronary artery disease, cerebrovascular disease and peripheral arterial disease as well as microvascular changes manifesting as neuropathy, nephropathy and retinopathy⁴. The duration of hyperglycemia is major risk factor for development of complications. Most of the complications manifest in the second decade of illness⁵.Diabetic nephropathy is characterized by persistent albuminuria (>300 mg/day) which is confirmed on at least two occasions at a gap of 3-6 months, progressive decline in glomerular filtration rate and increased arterial pressure⁶. It has been seen that about one third of newly diagnosed diabetic patients have some evidence of albuminuria. 75% of these have microalbuminuria and remaining 25% have overt diabetic nephropathy⁷. Diabetic nephropathy is the leading cause of mortality due to end stage renal disease⁸. In India, 30% of chronic renal failure is associated with diabetic nephropathy⁹. Microalbuminuria is the earliest evident manifestation of diabetic nephropathy¹⁰. It has been defined as excretion of albumin of 30 to 300 mg/d in a 24-h collection or 30 to 300 μg/mg creatinine in a spot collection¹¹. It is independent risk factor for cardiovascular complications as well as for future progression to overt nephropathy. Bruno et al demonstrated that there is progression of 3.7% of type 2 diabetic patients to overt nephropathy every year and microalbuminuria was associated with 42% increased risk as compared to normoalbuminuria¹². Early detection of microalbuminuria is helpful in ensuring aggressive glycemic control and other preventive measures to delay progress of nephropathy¹³. Various researchers have studied about prevalence and risk factors for microalbuminuria. Sinha et al found that 35% of type 2 diabetics suffered from microalbuminuria¹⁴. Varghese et al found it to be 36.3%¹⁵. Similar results were seen by Yadav et al at Jaipur (37%)¹⁶ and Chowta et al at Mangalore (37%)¹⁷. With changing epidemiology of lifestyle disorders and health programs focusing on these, it is essential to periodically monitor the situation. Hence, this study was conducted to assess the situation. Aims and objectives- The present study was conducted to find the prevalence of microalbuminuria in type-2 diabetic patients and to evaluate the relation between microalbuminuria and other risk factors.
MATERIAL AND METHODS

The present study was cross sectional in nature conducted at a Medical College and Hospital. Patients suffering from diabetes mellitus type 2 reporting to Medicine OPD were included in this study. Criteria for diagnosis of diabetes was fasting blood glucose level more than 126 mg/dl. Patients having proteinuria >=500 mg per day, congestive cardiac failure, urinary tract infection, pregnant patients and those on ACE inhibitors were excluded from this study. Patients with other established causes of microalbuminuria like chronic use of NSAID and connective tissue disorders were also excluded. The study conducted by Yadav et al in Jaipur¹⁶ found that the prevalence of microalbuminuria is 37%. Sample Size version 2.0 software was used to calculate sample size. Considering confidence level of 95%, proportion to be 37% and relative precision to be 20%, the sample size was calculated to be 164. It was rounded off to 200. A total of 13 patients did not complete the study and were not included. Thus, a total sample of 187 Patients was studied.

Pre tested semi-structured proforma was used for data collection. Previously diagnosed diabetic patients or in whom, diabetes was detected during visit to OPD were enrolled in this study. Detailed evaluation of all patients including history and clinical examination was done. Height, weight and BMI were measured. Blood pressure was recorded in sitting posture in right upper arm. Investigations included fasting blood sugar after overnight fast, serum cholesterol and lipid profile. Other investigations for inclusion or exclusion of the patients were also done. Detection of microalbuminuria- Early morning urine sample was collected. Urine was first tested for albumin by albustick test for presence of albumin. If it was negative, turbilatex test for microalbumin was used for detection of microalbuminuria. It is a quantitative turbidimetric test used for detection of microalbumin (µALB) in human urine in which latex particles coated with specific antibodies anti-human albumin are agglutinated when mixed with samples containing µALB. The agglutination causes as absorbance change, dependent upon the µALB contents of the patient sample that can be quantified by comparison from a calibrator of known µALB concentration. The test kit contains three reagents, namely Microalbumin Diluent, Microalbumin Latex and Calibrator. The detection limit of this test is less than 2 mg/L. The sample used was first morning urine specimen. pH of the urine was adjusted to 7.0 using NaOH/ HCl solutions. Urine was centrifuged before testing. Glucose (2 g/L), hemoglobin (10 g/L) and creatinine (3 g/L), do not interfere. Urea (1 g/L) and bilirubin (I0 mg/dL), interfere. Other substances may interfere¹⁸. When the results of this reagent were compared with that of commercial reagent, the correlation coefficient (r) was 0.99 and the regression equation was y= 0.964x –0.576¹⁹. Thus, the results of this test can be considered to be fairly accurate. Microalbuminuria was graded as mild (20-50 mg/l), moderate (50-100 mg/l) or severe (100-300 mg/l). The information was coded, data was entered in Microsoft Excel version 2007 and was analysed by SPSS version 16.0. Measurable variables were described in terms of Mean +/- SD and categorical variables were represented as frequency and percentage. Appropriate statistical tests were done for tests of significance. Pearson correlation test was done to assess the correlation of microalbuminuria with independent variables. P value less than 0.05 was considered as statistically significant. Informed consent was obtained from or all the patients and records were kept confidentially.

 

RESULT AND DISCUSSION

The present study included 187 diabetic patients fulfilling selection criteria and reporting to OPD of Medical College Hospital. Microalbuminuria was seen in 21.9% of diabetic patients. Table-1 shows the relation between various background factors and presence of microalbuminuria. It is seen that the mean age of patients with microalbuminuria is higher than those without microalbuminuria with significant difference (p=0.006). BMI among these groups was similar while fasting blood sugar was also significantly higher in the microalbuminuric group (p=0.000). Glycosylated haemoglobin was also higher in this group with significant difference (p=0.004). Thus, it was observed that microalbuminuria was associated with factors related to glycemic control. It was also seen that systolic blood pressure, diastolic blood pressure and serum creatinine were higher in microalbuminuric group (p<0.01).

Table 1: Showing association of microalbuminuria with background factors

Table-2 shows the association between duration of diabetes and microalbuminuria. It was seen that higher the duration of diabetes, higher the prevalence and this difference was statistically significant (p=0.00).

 

Table 2: showing association between duration of diabetes and microalbuminuria

Table-3 shows the result of logistic regression. It was observed that fasting blood sugar, glycosylated hemoglobin, systolic blood pressure and diastolic blood pressure were significantly higher in microalbuminuric group after adjusting for other factors.

Table 3: showing result of logistic regression

 

Prevalence of microalbuminuria has been studied by different researchers and has been found to be different in different places. The present study indicated the prevalence to be 21.9% while other reports have indicated it to range from 15% ²⁰ to 35.7%¹⁶. This variation is supposed to result from differences in population and that in study techniques. The relationship between microalbuminuria and age has been found to be linear which is similar to the findings of Chowta et al¹⁷. BMI did not appear to be significant factor which can be the result of confounding due to glycemic control. Microalbuminuria has been found to be strongly associated with fasting blood sugar, glycosylated haemoglobin and duration of diabetes. This is similar to the findings of Varghese et al¹⁵, Yadav et al¹⁶, Chowta et al¹⁷ and Sinha et al¹⁴ and supports the well established fact. It was also seen that renal damage was significantly associated with systolic and diastolic blood pressures and indicate that diabetic renal disease is aggravated by uncontrolled BP which is similar to the findings of Yadav et al¹⁶, Vijay et al²⁰ and Rema et al²¹. Microalbuminuria is part of generalized vascular derangement and is the early sign of renal damage. Its detection and proper management prevents the progression to diabetic nephropathy and finding of this study help in identification of risk factors and areas of intervention²². It also confirms that routine screening of microalbuminuria in diabetes patients is essential.

 

CONCLUSION

The present study concludes that about one-fifth of diabetic patients suffer from microalbuminuria which is strongly associated with glycemic control. Fasting blood sugar, glycosylated haemoglobin and duration of diabetes were three important factors with which microalbuminuria was associated.

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