Case Series of Histopathological Findings in Chronic Kidney Disease: Insights From the Kidney Precision Medicine...

The Kidney Precision Medicine Project is obtaining kidney biopsies from people with chronic kidney disease (CKD) and acute kidney injury for comprehensive clinical, histopathological, and molecular characterization. Here, we describe histopathological findings from a subset of kidney biopsies from adults with CKD.

Descriptive case series of histopathology findings from adjudicated CKD biopsies.

Kidney Precision Medicine Project enrolled adults with CKD and diabetes (DKD) and/or hypertension (HCKD) with persistent eGFR 30-59 mL/min/1.73 m², urine albumin-creatinine ratio ≥30 mg/g, or urine protein-creatinine ratio ≥150 mg/g. Clinicopathological adjudication by study nephrologists and kidney pathologists was completed as part of a pilot program for 39 participants enrolled 2019-2022. Clinicians completed surveys to assess impacts of biopsies on diagnosis, prognosis, and management.

This is a descriptive study without defined exposures.

Characterization of glomerular, tubulointerstitial, and vascular histopathological features across CKD biopsies.

Continuous variables were summarized as mean (standard deviation) or median (interquartile range); categorial variables were summarized as count (percentage).

Participants' mean age was 59 years, 59% were female. Mean eGFR was 55 mL/min/1.73 m²; median urine albumin-creatinine ratio and urine protein-creatinine ratio were 81 mg/g and 211 mg/g, respectively. Among DKD-enrolled participants (N = 28), 15 (54%) had a primary diagnosis of diabetic nephropathy, 3 (11%) had hypertension-associated nephropathy, 2 (7%) had other glomerular diseases, and 8 (29%) had nonspecific findings. Among HCKD-enrolled participants (N = 11), 5 (46%) had hypertension-associated nephropathy and 6 (55%) had nonspecific findings. A range of glomerular, tubulointerstitial, and vascular findings was observed. 26% of clinicians stated results were different than expected; 77% stated results affected prognostic discussions.

Small sample size and lack of longitudinal data limit generalizability.

Kidney biopsies in people with common causes of CKD demonstrate a broad range of histopathology and may have clinical utility. Unsuspected disease processes and unexpected and nonspecific findings precluding a definitive diagnosis are often present.