Evaluation of renal damage by urinary beta-trace protein in patients with chronic kidney disease.

BACKGROUND

Beta-trace protein (BTP) was found to be increased in the serum and urine of patients with renal diseases. The aim of this study was to compare the urinary levels of beta-trace protein with levels of other urinary proteins: albumin, beta2-microglobulin (B2M), alpha1-microglobulin (A1M), and cystatin C and to determine its clinical usefulness for detection of renal dysfunction in chronic kidney disease (CKD).

METHODS

These markers were measured in 24-hour urine samples from 134 patients with CKD.

RESULTS

BTP correlated significantly with A1M (r = 0.871), cystatin C (r = 0.759), total protein (r = 0.684), B2M (r = 0.497), and albumin (r = 0.448) in 24-hour urine samples (P < 0.05). Urinary BTP concentrations in patients with albuminuria below 30 mg/day were significantly lower than in patients with albuminuria above 30 mg/day (P < 0.0001). ROC analysis showed high diagnostic accuracy of BTP for detection of > 30 mg/day albuminuria (AUC 0.908). Urinary BTP was also in significant correlation with the estimated glomerular filtration rate (r = -0.580).

CONCLUSIONS

The results of our study suggest that BTP may be a useful and reliable urinary marker of renal dysfunction and may have a place in addition to urinary alpha1-microglobulin and albumin as an alternative marker for tubular damage and the magnitude of renal impairment in patients with chronic kidney disease.