title: The modern spectrum of renal biopsy findings in patients with diabetes.
abstract: OBJECTIVE
  Renal biopsies performed in diabetic patients are increasing in number and complexity. This study sought to determine the usefulness of renal biopsy in patients with diabetes and the predictability of diagnosing diabetic nephropathy (DN) versus nondiabetic renal disease (NDRD) from clinical and laboratory data.
  
  
  METHODS
  To assess modern trends, a retrospective study was performed of clinical-pathologic findings in all patients with diabetes who had a biopsy in 2011. Among 2642 native kidney biopsies, 620 (23.5%) were from patients with diabetes.
  
  
  RESULTS
  The cohort included 371 men (60.7%) aged a median (interquartile range) 62 years (52-69) with 10-year (5-15) duration of diabetes mellitus (DM). Median serum creatinine was 2.5 mg/dl (1.6-4.4), and 52% of patients had stage 4-5 CKD. On biopsy, 37% of patients had DN alone, 36% had NDRD alone, and 27% had DN plus NDRD. In NDRD alone, FSGS (22%), hypertensive nephrosclerosis (18%), acute tubular necrosis (ATN) (17%), IgA nephropathy (11%), membranous GN (8%), and pauci-immune GN (7%) comprised 80% of diagnoses, compared with ATN (43%), hypertensive nephrosclerosis (19%), FSGS (13%), and IgA nephropathy (7%) for DN plus NDRD. In multivariate analyses, longer duration of DM was associated with a greater likelihood of DN and a lower likelihood of NDRD: each added year of DM reduced the odds of NDRD by 5% (odds ratio, 0.95; 95% confidence interval, 0.91 to 0.98; P=0.004). DM duration ≥ 12 years was the best predictor (58% sensitivity, 73% specificity) of DN alone.
  
  
  CONCLUSIONS
  Approximately one-quarter of all renal biopsies are performed in patients with DM. Judicious use of renal biopsy has uncovered NDRD alone or superimposed on DN in the majority of such biopsies. ATN is emerging as an important category of NDRD, which has not been reported previously.
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas;, †Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York, ‡Department of Pathology, Columbia University Medical Center, New York, New York.
authors.forename: Shree G
authors.initials: SG
authors.lastname: Sharma
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Bomback
authors.forename: Jai
authors.initials: J
authors.lastname: Radhakrishnan
authors.forename: Leal C
authors.initials: LC
authors.lastname: Herlitz
authors.forename: Michael B
authors.initials: MB
authors.lastname: Stokes
authors.forename: Glen S
authors.initials: GS
authors.lastname: Markowitz
authors.forename: Vivette D
authors.initials: VD
authors.lastname: D'Agati
mesh_terms: D000368:Aged; D001706:Biopsy; D003920:Diabetes Mellitus / Q000473:pathology*; D003928:Diabetic Nephropathies / Q000175:diagnosis*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007674:Kidney Diseases / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies