Background: The glomerular and retinal vessels are both affected in patients with type I and type II diabetes mellitus. However, the prevalence of the nodular form of diabetic glomerular sclerosis (Kimmelstiel Wilson lesion) and other forms of glomerular pathology including diffuse mesangial sclerosis and their clinical correlates in type II diabetes are less well known. In addition, although recent studies have suggested that non-diabetic glomerular disease was a common cause of proteinuria in type II diabetes, the prevalence of other diseases is unknown. The literature on this subject is clouded by clinical bias regarding patients with diabetes who undergo renal biopsy.
Methods: Glomerular and retinal pathology and clinical correlates were studied in 36 patients enrolled in a prospective clinical trial of patients with type II diabetes mellitus, proteinuria, renal insufficiency, and hypertension.
Results: Seventeen biopsies had diabetic glomerular sclerosis with Kimmelstiel Wilson nodules; 15 biopsies had glomerular changes characteristic of the diabetic state including enlarged glomeruli and an increase in mesangial matrix without Kimmelstiel Wilson nodules (mesangial sclerosis lesion); and two had other primary glomerular diseases (IgA and membranous nephropathy). Patients with Kimmelstiel-Wilson nodules had elevated serum creatinines compared to patients with mesangial sclerosis lesions, but there were no other significant differences. Patients with Kimmelstiel Wilson nodules had more severe overall retinopathy than those with mesangial sclerosis lesions (P = 0.0043): six of seven with proliferative retinopathy had Kimmelstiel Wilson nodules, and seven of the eight patients without retinopathy had mesangial sclerosis lesions.
Conclusions: The two discrete patterns of glomerular pathology and the correlation between diabetic retinopathy and the Kimmelstiel-Wilson lesion but not the mesangial sclerosis lesion suggest that the Kimmelstiel Wilson and mesangial sclerosis lesions of diabetic glomerulosclerosis are caused by different pathogenetic mechanisms. In this study, diabetic glomerulosclerosis was responsible for the clinical renal abnormalities in 94%, of patients with type II diabetes mellitus.