Clinical significance of microscopic haematuria in diabetic nephropathy in type 2 diabetes patients with overt proteinuria.

AIM: Although some patients with diabetic nephropathy with overt proteinuria have microscopic haematuria, the pathological characteristics and clinical significance related to microscopic haematuria have not yet been clarified. The aim of the present study was to clarify the pathological characteristics and clinical significance of microscopic haematuria.
METHODS: Eighty-four type 2 diabetes patients with overt proteinuria and biopsy-confirmed diabetic nephropathy were enrolled. The clinical and histological findings were compated between the patients with persistent haematuria (group 1, n=25) and those with persistent non-haematuria (group 2, n=23) after renal biopsy. The association between persistent haematuria and renal outcome at 5 years was examined. Histological scoring was made according to the original system and that of Tervaert et al.
RESULTS: Thirty-six patients (43%) had microscopic haematuria at the time of renal biopsy. Age was significantly smaller and blood pressure was significantly greater in group 1 than in group 2 (age: group 1, 56 ± 10 years; group 2, 62 ± 9 years; P=0.03, systolic blood pressure: group 1, 152 ± 16 mm Hg; group 2, 140 ± 16 mm Hg; P=0.01). There were no significant differences in histological parameters between the two groups. A logistic regression model demonstrated that arteriolar hyalinosis was significantly associated with persistent haematuria (OR=2.81; P=0.04). There were no significant differences in changes in reciprocal serum creatinine and rates of doubling of serum creatinine after renal biopsy between the two groups.
CONCLUSION: Although arteriolar hyalinosis was associated with persistent haematuria, the clinical significance of microscopic haematuria was minor in diabetic nephropathy in type 2 diabetes patients with overt proteinuria.