Kidney Biopsy in Type 2 Diabetes: A Multicenter Cross-Sectional Study

Area of Science:

• Nephrology
• Diabetology
• Internal Medicine

Background:

• Kidney biopsies (KBs) in type 2 diabetes (T2D) help differentiate diabetic nephropathy from non-diabetic or hypertensive kidney disease (NDHKD).
• Indications for KB are typically based on atypical features suggesting NDHKD, deviating from the expected course of diabetic nephropathy.

Purpose of the Study:

• To assess the association between specific atypical features (KB indications) and the diagnosis of NDHKD in patients with T2D.
• To identify predictors of NDHKD in T2D patients undergoing kidney biopsy.

Main Methods:

• Analysis of native kidney biopsies (KBs) from 463 patients with T2D.
• Evaluation of indications for KB, including recent nephrotic syndrome, declining eGFR, increased proteinuria, short diabetes duration, hematuria, and normal retinal exam.
• Logistic regression analysis to identify predictors of NDHKD.

Main Results:

• NDHKD was diagnosed in 40% of the total T2D population studied.
• Indications 1-4 (any atypical feature, nephrotic syndrome, declining eGFR, increased proteinuria) were associated with higher NDHKD prevalence (54%, 40%, 24%, 7% respectively).
• Predictors of NDHKD included eGFRCKD-EPI >15 mL/min/1.73 m2, urinary protein-to-Cr ratio <0.3 g/mmol, hematuria, HbA1c <7%, and diabetes duration <5 years.

Conclusions:

• Non-diabetic or hypertensive kidney disease (NDHKD) is prevalent in type 2 diabetes (T2D).
• While hematuria can be associated with NDHKD, it's insufficient for KB indication without other atypical features.
• Rapidly progressing proteinuria and deteriorating eGFR are key indicators for suspecting NDHKD in T2D patients.