Pathologic Diabetic Nephropathy in Autopsied Diabetic Cases With Normoalbuminuria From a Japanese Community-Based Study

Abstract

Introduction: Albuminuria is a clinical hallmark of diabetic nephropathy (DN). Nevertheless, it is controversial whether pathologic DN lesions exist in individuals with diabetes with normoalbuminuria. We investigated the association between albuminuria levels and the frequency of DN lesions in autopsied diabetic cases from a Japanese community.Methods: A total of 106 autopsied cases with diabetes mellitus (mean age ¼ 76 years, 43.4% male) who died within 6 years after their last health examination were included in the study. Urinary albumincreatinine ratio (UACR) levels were divided into the following 3 groups: <30.0, 30.0 to 299.9, and $300.0 mg/g. The kidney specimens were evaluated with light microscopy. Glomerular DN lesions were categorized into class 0 to I, IIa, IIb, and III glomerular DN lesions according to the criteria of the Renal Pathology Society. A Cochran-Armitage test was used to evaluate the association between the UACR levels and the presence of class IIa or higher glomerular DN lesions. Results:The frequency of class IIa or higher glomerular DN lesions was 63.2% (IIa, 36.8%; IIb, 3.8%; and III, 22.6%) among overall cases. The frequencies increased significantly with higher UACR levels (P for trend ¼ 0.02). The frequency of class IIa or higher glomerular DN lesions was 51.2%, even in individuals with UACR < 30 mg/g. Conclusion:This study revealed a positive association of the UACR levels with the presence of class IIa or higher glomerular DN lesions, which were also frequently found even in the normal range of UACR levels, among autopsied diabetic cases from a Japanese community.

Diabetic Kidney Disease: The “Silent” Majority?

“…The study by Sasaki et al. 6 had some limitations. First, electron microscopic examination of the kidney tissue was not performed; thus, the prevalence of early diabetic changes (such as thickening of the glomerular basement membrane) could not be determined.…”

“…The study by Sasaki et al. 6 published in this issue of KI Reports is apropos as it helps to identify the burden of clinically silent DKD. In their study, Sasaki et al.…”

“…In their study, Sasaki et al. 6 used the Hisayama cohort, a longitudinal study of cardiovascular disease in a Japanese population. In this study, patients had routine clinical examinations, and on their death, most had an autopsy.…”

Response to “Letter Regarding Normal Albuminuria in Patients With Autopsy-Proven Advanced Diabetic Nephropathy”

“…We thank Heyman and colleagues (1) for their letter regarding our paper reporting the 2 association between albuminuria levels and pathological diabetic nephropathy from a 3 Japanese community-based study (2). They suggest further evaluating the association…”

Letter Regarding Normal Albuminuria in Patients With Autopsy-Proven Advanced Diabetic Nephropathy

“…In the 2021 December issue of the KI Report , Sasaki et al. 1 point out that nearly half of 106 Japanese patients with a stage IIa or higher diabetic glomerulopathy, evident on autopsy, were “normoalbuminuric” (urine albumin-to-creatinine ratio <30 mg/g) up to 3 years before death. While addressing this enigma, they ignored the mitigating impact of tubular handling of filtered albumin on albuminuria.…”