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Woo KT, Chan CM, Lim C, Choo J, Chin YM, Teng EWL, Mok I, Kwek JL, Tan CS, Tan HZ, Loh AHL, Choong HL, Tan HK, Lee GSL, Lee E, Wong KS, Tan PH, Foo M: The Value of Renal Biopsy in Non-Insulin-Dependent Diabetes Mellitus in Singapore over the Past Two Decades. Kidney Diseases DOI 10.1159/000505624
Kidney biopsy in patients with diabetes mellitus (typically type 2; T2DM) and CKD (proteinuria with or without reduced GFR) is often performed to evaluate the possibility of the presence of a non-diabetes-related lesion/disease (NDRD) alone or in combination with diabetic nephropathy (DN); however, clinical protocols for deciding when such kidney biopsies are indicated vary widely. Previous studies have suggested that the prevalence of pure DM, NDRD, and NDRD + FN is found in such “clinically indicated” biopsies in 6.5–94, 3–89, and 4–48%, respectively. Renal biopsies done for research purposes only, not guided by clinical indications, reveal NDRD with or without DN in about 10–15% of patients with T2DM.
In a single-center retrospective study extending over a period of about 4 decades, Woo and coworkers from Singapore have studied the findings of elective, “clinically indicated” kidney biopsies in 255 patients with T2DM and CKD. The patients in whom the biopsies revealed only DN tended to be younger, have higher blood pressure, more retinopathy, lower eGFR, and greater proteinuria compared to those in whom NDRD lesions were found. IgA nephropathy, membranous nephropathy, and minimal change disease were commonly encountered NDRD lesions. Focal and segmental glomerulosclerotic (FSGS) lesions were represented in both NDRD and NDRD + DN categories, but not among pure DN. This may be an artifact of classification as it is very difficult to separate DN-associated FSGS for other forms of FSGS lesions, including primary, genetic, and secondary forms. Diabetic retinopathy was strongly associated with Kimmelstiel-Wilson (nodular) glomerulosclerosis. Dysmorphic hematuria and a short duration of clinical manifestations of CKD were strongly associated with NDRD, with or without DN. High systolic blood pressure, a longer duration of diabetes, marked proteinuria, and diabetic nephropathy were all associated with a greater risk of progression to ESKD.
This and other similar studies support the common practice of performing a renal biopsy whenever there is a clinical suspicion of NDRD in a patient with T2DM and CKD. A short duration of diabetes, absence of retinopathy dysmorphic hematuria, and rapidly declining renal function are useful clinical features suggesting that NDRD may be present.
Quoted Karger Article
