Microalbumin Status in Relation to Glycated Haemoglobin and Duration of Type 2 Diabetes Mellitus

BACKGROUND: Diabetes mellitus (DM) is one of the most common endocrine disorders, characterized by hyperglycemia. Diabetic nephropathy is a consequence of longstanding diabetes and urinary microalbumin (Uma) status predicts progression to diabetic nephropathy. This study was conducted to know the status of Uma in relation to duration of diabetes and HbA1c level in patients with Type 2 diabetes mellitus (T2DM).


Introduction
Diabetes Mellitus (DM) is a chronic, widely prevalent endocrine disease, which is characterized by hyperglycemia due to defects in insulin secretion, insulin action or both [1].Diabetic nephropathy is most common complication of long-standing diabetes mellitus [2].Persistent microalbuminuria (MAU) is the best predictor of progression to end-stage renal disease (ESRD) as well as cardiovascular complications [3].Till date, different studies have been performed to find out the relationship between MAU, glycosylated haemoglobin (HbA 1c ) and duration of diabetes.All the studies have not shown similar results and the relation between these parameters are not clear.This study was conducted to explore the underlying relationship between these parameters in our context.

Methods
This prospective cross sectional study was conducted on total 96 patients with T2DM.This study was carried out in Biochemistry Laboratory, Tribhuvan University Teaching hospital (TUTH) from July 1, 2014 to January 15, 2015.In this study, T2DM subjects having HbA 1c value >6.3%, who gave written consent were included under this study.Simultaneously, history of duration was taken and required informations were noted.HbA1c was estimated using NyCocard boronate affinity assay and Uma concentration was measured in spot urine sample using NyCocard immunometric assay.NyCocard Reader II was used for measurement of both HbA 1c and urinary microalbumin.Before performing microalbumin test, the urine sample was tested by uristrip method to exclude overt proteinuria from this study.MAU was diagnosed if albumin was between 20-200 mg/L.[6].ShonimaVenugopal and Uma M lyer showed statistically significant correlation of UMA and HbA1c level (p< 0.05) [12].Manjrekar et al has reported gradual increase in prevalence of MAU with similar increase in HbA1c level [13].Similarly, Gupta et al performed an independent study and reported strong association of HbA1c level with urinary microalbumin excretion [14].The difference in results may be due to limited sample size.Hence, further study with a larger sample is necessary in order to confirm the result obtained in present study.
This study shows conclusive evidence that urinary microalbumin excretion was significantly correlated with duration of the disease and level of HbA1c positively correlated with urinary microalbumin although statistically insignificant.Duration of diabetes contributes for the development of MAU and then diabetic nephropathy by prolonged exposure to hyperglycemia induced advanced glycosylation end products.

Conclusion
Overall prevalence of microalbuminuria in T2DM was 39.6%.Urinary microalbumin excretion correlated significantly with duration of diabetes.Increased HbA1c level positively correlated with MAU, although statistically insignificant.Regular screening for urinary microalbumin as well as HbA1c and good glycemic control is recommended in such patients.

Table 1 :
Overall prevalence of MAU in the present study was 39.6 % (38/96).Among total 54 males, prevalence of UMA was 44.4% (24/54).And among 42 females, prevalence of UMA was 33.3 % (14/42).Mean age of patients with UMA was 61.42±7.45years and in normoalbuminuric patients it was 59.21±8.49years.Duration of diabetes ranged between 6 months and 18 years.Out of total 96 patients, 52 had duration of diabetes <5 years and among them 18 (34.6%) had MAU.Twenty six had duration of diabetes ≥5 to 10 years, among them 10 (38.5 %) had MAU.Twelve had duration of diabetes ≥10 to 15 years, among them 6 (50.0 %) had MAU, and six had duration of diabetes ≥15 years, among them 4 %) had MAU [Table.1].Mean duration of diabetes in microalbuminuric patients was 7.71±5.65 years while in normoalb-uminuric patients it was 5.17±4.32years, which was statistically significant.Pearson correlation analysis showed statistically significant correlation of MAU with duration of diabetes (r= 0.471, p < 0.05) [Table 3].Prevalence of microalbuminuria in relation to duration of T2DM

Table 2 :
Prevalence of microalbminuria in relation to HbA1c level in T2DM