Type 2 diabetic patients with diabetic retinopathy and concomitant microalbuminuria showed typical diabetic glomerulosclerosis and progressive renal dysfunction.

Aims: To determine whether or not diabetic retinopathy (DR) in type 2 diabetic patients can predict the renal functional decline.

Methods: We examined 32 normo-microalbuminuric type 2 diabetic patients by renal biopsy (23 men, age 49±10yrs) divided into two groups according to the presence (n=19) or absence (n=13) of DR. Electron microscopic morphometry including mesangial fractional volume [Vv(Mes/glom)] were performed and light microscopic tissues were categorized as: C1, normal/near normal renal structure; C2, typical diabetic glomerulopathy; C3, atypical injury patterns. Patients were followed up for 7.1±3.8years, and glomerular filtration rate (GFR) and urinary albumin excretion (UAE) measurements were taken annually.

Results: Vv(Mes/glom) was larger in DR+ than that in DR-. Vv(Mes/glom) positively correlated with the UAE if patients had DR. The patients with DR had a significant higher rate of C2 pattern compared to those in DR-. Among patients with DR and C2, GFR in microalbuminuria (n=7) decreased while GFR in normoalbuminuria (n=5) did not change during the observation.

Conclusions: Type 2 diabetic patients with DR and C2 showed progressive renal dysfunction after they had microalbuminuria. DR and albuminuria should be considered to determine renal function decline in type 2 diabetic patients.