The Role of Vascular Lesions in Diabetes Across a Spectrum of Clinical Kidney Disease

Introduction: The clinical-histologic correlation in diabetic nephropathy is not completely known. Methods: We analyzed nephrectomy specimens from 90 patients with diabetes and diverse degrees of proteinuria and glomerular filtration rate (GFR). Results: Thirty-six (40%) subjects had normoalbuminuria, 33 (37%) microalbuminuria, and 21 (23%) nonnephrotic proteinuria. Mean estimated GFR (eGFR) was 65 +/- 23 (40% <60 ml/min per 1.73 m(2)). About 170 glomeruliper patientwereanalyzed, andallsamplesincludedvascular tissue. Six subjects(7%) wereclassifiedin diabetic nephropathy class I, 61 (68%) in class II-a, 13 (14%) in class II-b, 9 (10%) class III, and 1 (1%) in class IV. Eighty percent to 90% of those with normoalbuminuria or microalbuminuria were classified in class II-a or II-b and <10% in class III; 52% of those with proteinuria were in class II-a, 15% in class II-b, and 19% in class III. Nodular sclerosis (57%) and mesangial expansion (15%) were more frequent in cases with proteinuria than in normoalbuminuria (28% and 8%; P = 0.028 and 0.017). About 20% to 30% of all cases, regardless the level of albuminuria or proteinuria or the histologic class had tubular atrophy, interstitial fibrosis, or inflammation in >10% to 20% of the sample. Moderate hyalinosis and arteriolar sclerosiswere observed in 80% to 100% of cases with normoalbuminuria, microalbuminuria, proteinuria, as well as in class I, II, or III. Conclusions: Weak correspondence between analytical parameters and kidney histology was found. Thus, disease may progress undetected from the early clinical stages of the disease. Finally, vascular damage was a very common finding, which highlights the role of ischemic intrarenal disease in diabetes.

Automated summary

The clinical-histologic correlation in diabetic nephropathy is not fully understood. Analysis of nephrectomy specimens showed weak correspondence between analytical parameters and kidney histology, suggesting disease progression may go undetected in early stages. Vascular damage was a common finding, emphasizing the role of ischemic intrarenal disease in diabetes.