COMPARISON OF URINARY FIBRONECTIN AND LAMININ WITH MICROALBUMINURIA AS MARKERS OF GLOMERULAR INJURY IN TYPE 2 DIABETES MELLITUS PATIENTS

Abstract

BACKGROUND
About one-third of Diabetes Mellitus (DM) patients are complicated by diabetic
kidney disease. It is even more challenging in type 2 DM in which this
complication may occur even before presentation. Traditionally,
microalbuminuria is the first marker of early diabetic nephropathy. However,
there are many limitations, chief amongst them is that it may occur when
significant renal damage has already occurred.

AIM
The aim of this study was to evaluate and compare urinary fibronectin and
laminin with microalbuminuria as markers of glomerular injury in type 2 DM
patients.

METHODOLOGY
This cross-sectional study was done with a total of 120 consenting type 2 DM
patients without hypertension. They consisted of 57 (47.5%) males and 63
(52.5%) females; while 120 non-diabetic/non-hypertensive subjects were
recruited as controls, consisting of 51 (42.5%) males and 69 (57.5%) females.
Urinary albumin was measured using the immunoturbidimetric assay, urinary
fibronectin and laminin were measured using the ELISA technique. Plasma
glucose, creatinine (plasma/urine) were measured by the glucose oxidase
method and modified Jaffe method respectively. Statistical analysis was done
using statistical package for social science (SPSS version 16), results were
expressed as mean ± SD, Chi-square tests and students t test were used as
appropriate. A p-value of less than 0.05 was considered statistically significant.

RESULTS
The mean albumin –creatinine ratio was significantly higher (p<0.001) among
those with type 2 DM (1.99+ 3.02 mg/mmol) in comparison to the controls
(0.12+ 0.37 mg/mmol). Also, among those with type 2 DM, the urinary
fibronectin (1.29+1.69 µg/mL) and urinary laminin (1251.34+1656.36 pg/mL)
were significantly higher (p<0.001) than those of the controls (0.29+ 0.3 µg/mL
and 127.81+147.60 pg/mL) respectively. Thirty-three (27.5%) of the subjects
with type 2 DM were microalbuminuric as compared to none in the controls.
The sensitivity test for both urinary fibronectin and laminin was 93.9%.
However, their specificities were low at 8.0% and 13.8% respectively. The
negative predictive value (NPV) for urinary fibronectin was 77.8% while that of
urinary laminin was 85.7%. Their positive predictive values (PPV) were 27.9%
and 29.2% respectively.

CONCLUSION
The mean urinary fibronectin and laminin are significantly raised among
subjects with type 2 DM. Although, urinary fibronectin and laminin, showed
high sensitivities and high negative predictive values they are limited in their
usefulness for the early detection of diabetic kidney disease due to their low
specificities and low negative predictive values.

COMPARISON OF URINARY FIBRONECTIN AND LAMININ WITH MICROALBUMINURIA AS MARKERS OF GLOMERULAR INJURY IN TYPE 2 DIABETES MELLITUS PATIENTS