Temporal and Demographic Trends in Biopsy-Proven Kidney Disease Diagnoses in the Southwestern United States, 1993-2022

Abstract

Rationale & objective: Kidney biopsy is vital to diagnose and manage medical kidney diseases. However, not many large-scale studies for medical kidney disease have been reported worldwide. We describe 30-year temporal and demographic trends in biopsy-proven glomerular and nonglomerular diseases in the Southwestern United States.

Study design: Retrospective single-center cohort study.

Setting & participants: Native kidney biopsy cases referred to the Renal Pathology Service at Cedars-Sinai Medical Center between 1993 and 2022.

Predictors: Biopsy era (1993-2002, 2003-2012, and 2013-2022) and demographics (age, sex, and race) were primary and secondary predictors.

Outcomes: Relative frequencies (percentages) of 35 widely recognized glomerular/ nonglomerular disease categories are primary outcome.

Analytical approach: Non-numerical and numerical variables were compared using χ² test and analysis of variance, followed by Tukey-Kramer post hoc tests.

Results: In total, 57,613 patients were identified, with a mean age 51.0 (± 19.2) years, 52.2% men, 53.8% White, 19.5% Latino, 11.0% Black, 10.2% Asian, and 5.5% other race. Glomerular disease relative frequency was always higher than nonglomerular disease frequency. Among the glomerular diseases, the relative frequency of diabetic glomerulosclerosis in our cohort was constantly and rapidly increasing, whereas those of other glomerular disease categories were decreasing except for antineutrophil cytoplasmic antibody/pauci-immune glomerulonephritis. However, the decline in the relative frequency of glomerular diseases was much less apparent when diabetic glomerulosclerosis was removed. Among the nonglomerular diseases, acute tubular necrosis was increasing in frequency. These temporal trends were largely preserved in all demographic subgroups, although there were several cross-sectional differences of glomerular disease frequencies within each demographic subgroup.

Limitation: Retrospective and observational study design, no patient/kidney outcomes, some missing patients' data, and possible misclassification of disease categorization.

Conclusions: To our best knowledge, we provided the largest and latest medical kidney biopsy data, which may provide valuable insights to predict the relative likelihood of a disease diagnosis in a daily medical practice.

Keywords: Diabetic nephropathy; glomerular disease; glomerulonephritis; kidney biopsy; medical kidney disease; nonglomerular disease.

Figure 1

Temporal trends in the relative kidney biopsy frequencies of the most common 8 glomerular and 4 nonglomerular diseases. (A) Frequencies of the most common 8 glomerular disease categories shown as a proportion of the entire cohort. (B) Frequencies of the most common 7 glomerular disease categories without DGS, shown as a proportion of the entire cohort. (C) Frequencies of the most common 4 nonglomerular disease categories shown as a proportion of the entire cohort. Abbreviations: DGS, diabetic glomerulosclerosis; FSGS, focal segmental glomerulosclerosis; IC-GN, immune complex-mediated glomerulonephritis; IgAN, IgA nephropathy; LN, lupus nephritis; MCD, minimal change disease; MN, membranous nephropathy.

Figure 2

Distribution of glomerular and nonglomerular diseases in age category. (A) All glomerular disease categories: number of patients with each of the 8 most common glomerular disease categories shown. (B) Nephrotic/proteinuric subtypes: number of patients with each of the 6 most common glomerular disease categories that often clinically present with nephrotic syndrome shown. (C) Nephritic subtypes: number of patients with each of the 6 glomerular disease categories that often clinically present with nephritic features shown. (D) Nonglomerular disease categories: number of patients with each of the 4 nonglomerular disease categories shown. Abbreviations: DGS, diabetic glomerulosclerosis; FSGS, focal segmental glomerulosclerosis; IC-GN, immune complex-mediated glomerulonephritis; IgAN, IgA nephropathy; LN, lupus nephritis; MCD, minimal change disease; MIDD, monoclonal immunoglobulin deposition disease; MN, membranous nephropathy; TBM, thin basement membrane; TMA, thrombotic microangiopathy.

Figure 3

Distribution of glomerular diseases in age category stratified by sex and race. Number of (A) male, (B) female, (C) White, (D) Latino, (E) Black, and (F) Asian patients with each of the 8 most common glomerular disease categories shown. Abbreviations: DGS, diabetic glomerulosclerosis; FSGS, focal segmental glomerulosclerosis; IC-GN, immune complex-mediated glomerulonephritis; IgAN, IgA nephropathy; LN, lupus nephritis; MCD, minimal change disease; MN, membranous nephropathy.

Figure 4

Relative kidney biopsy diagnosis frequencies of the most common glomerular diseases according to patient age category. (A) Nephrotic/proteinuric subtypes; (B) nephritic subtypes. Abbreviations: DGS, diabetic glomerulosclerosis; FSGS, focal segmental glomerulosclerosis; IC-GN, immune complex-mediated glomerulonephritis; IgAN, IgA nephropathy; LN, lupus nephritis; MCD, minimal change disease; MIDD, monoclonal immunoglobulin deposition disease; MN, membranous nephropathy; TBM, thin basement membrane; TMA, thrombotic microangiopathy.

Figure 5

Temporal trends in the absolute kidney biopsy frequencies of FSGS. Abbreviation: FSGS, focal segmental glomerulosclerosis.