#2685 Research kidney biopsies in type 2 diabetes: clinical and laboratory parameters alone are not enough to identify candidates for kidney biopsy

Background and Aims
Type 2 diabetes is present in approximately one-third of patients with chronic kidney disease (CKD), making it crucial to ensure correct diagnosis and treatment of the underlying kidney disease. Most individuals with CKD and type 2 diabetes do not undergo a kidney biopsy and are directed to standard diabetic-CKD-management, risking misdiagnosis and wrong treatment if non-diabetic kidney disease is present. Identifying clinical characteristic that help predict when a biopsy will alter management could help optimize patient selection for diagnostic kidney biopsy.

The aim of this study was to evaluate clinical and laboratory parameters in patients with type 2 diabetes and severe albuminuria undergoing research kidney biopsies, comparing patients whose biopsy results led to changes in clinical management with those who continued conventional diabetes-CKD treatment.

Method
We have established an ongoing national prospective cohort, PRIMETIME 2, where we aim to conduct research kidney biopsies in 300 adult patients with type 2 diabetes and severe albuminuria (urine albumin-to-creatinine ratio (UACR) >700 mg/g) and simultaneously collect a broad range of clinical data and biological samples.

In this preliminary analysis of the first 95 patients, we categorized renal pathology diagnoses into two groups based on clinical implications: (1) a “no change”-group requiring conventional diabetes-CKD-management (including diabetic nephropathy, hypertensive nephropathy, and/or non-nephrotic FSGS), and (2) an “altered management”-group with diagnoses leading to altered clinical management (including IgA nephropathy, membranous nephropathy, minimal change disease, and amyloidosis). We compared clinical and laboratory parameters between groups with adjustment for multiple comparisons.

Results
Of 95 participants, 84 patients (88%) were categorized in the “no change”-group and 11 patients (12%) had diagnoses leading to altered management (Table 1). The groups were comparable regarding age, diabetes duration, diabetic complications, number of comorbidities, estimated GFR, HbA1c and microscopic hematuria. The significant differences between groups were mainly related to protein excretion, with the “altered management”-group showing higher UACR and lower P-albumin, but with considerable overlap of ranges between the two groups.

Conclusion
Clinical and laboratory parameters alone cannot reliably differentiate between patients with diabetes and severe albuminuria whose kidney biopsy findings will or will not change clinical management. Although p-albumin and UACR showed significant differences between the two groups, the extensive overlap in their ranges limits their use as reliable predictors. New tools, such as biomarkers, are necessary to better direct kidney biopsies in patients with diabetes and severely elevated albuminuria to diagnose and rightfully treat non-diabetic kidney disease.