The purpose of this study was to determine the relationship between kidney size and diabetic renal lesion in non-insulin-dependent diabetes mellitus (NIDDM). Kidney size was measured in 22 normal controls and 67 diabetic patients (9 cases with persistent proteinuria, 36 cases with retinopathy) and was expressed as the renal ratio determined by the method of Simon using intravenous pyelograms. Renal biopsy was performed in 19 diabetics and diabetic glomerular diffuse lesion was graded into four classes based on Gellman's classification.
The following results were obtained;
1) The renal ratio was significantly larger in diabetic patients than in the controls (p<0.01).
2) Based on renal ratio in the controls, the diabetics were subdivided into S (mean-SD≥) M (mean-SD-mean+SD) and L (mean+SD ≤) groups. Cases of diabetics belonging to the S, M and L groups were 4, 32 and 31 respectively. Persistent proteinuria was found in 0, 6.3 and 22.2% of the patients in the S, M and L group respectively.
3) In 19 diabetics whose kidneys were biopsied, glomerular diffuse lesion was grade I or II in all seven cases in the M group, and grade III or IV in six out of twelve cases in the L group. Kidneys with glomerular diffuse lesion of grade III or IV were significantly larger than those with glomerular diffuse lesion of grade I or II (p<0.05).
From these results, it was concluded that in the NIDDM risk of progression into persistent proteinuria was higher in patients with enlarged kidneys than in those without it.