Renal biopsy in patients with type 2 diabetes mellitus: indications and nature of the lesions

BACKGROUND AND OBJECTIVES: The prevalence of non diabetic renal disease (NDRD) among patients with type 2 diabetes mellitus varies widely depending on the selection criteria and the populations being studied. The aim of this study was to evaluate the renal biopsies performed on type 2 diabetic patients for suspicion of NDRD and to correlate the pathological with the clinical and laboratory findings. SUBJECTS AND METHODS: We selected and reviewed biopsies performed on type 2 diabetics for clinically suspected NDRD from January 2006 to December 2008 at a single hospital. Clinical and laboratory data were analyzed in relation to the histopathology findings. Patients were grouped into either group I with isolated DGS or group II with NDRD on top of DGS. RESULTS: Thirty-one biopsies were performed on type 2 diabetic patients; Seventeen patients (54.8%) were males. Mean age was 50.68 (11.29) years. The mean duration of diabetes was 9.33 (3.6) years. Renal biopsy showed that among the studied group 14 patients (45.2%) showed NDRD on top of DGS. Crescentic glomerulonephritis was the commonest finding seen in 3 cases (21.4% of group II cases) followed by acute tubulointerstitial nephritis and hypertensive changes each was seen in 2 cases (14.4%). Other findings included IgA nephropathy, primary focal segmental glomerulosclerosis, rhabdomyolysis, membranoproliferative glomerulonephritis each of them was seen in one case (7.1%). Group I had a significantly higher level of proteinuria 4.97 (2.08) gm/24 hrs urine than group II 2.72 (1.09) gm/24 hrs urine (P=.003). There was no significant difference between the two groups in age, duration of diabetes, gender, presence of hypertension, hematuria, serum creatinine or glomerular filtration rate. CONCLUSION: The present study showed that crescentic glomerulonephritis is the commonest NDRD among diabetic patients. A higher level of proteinuria was reported among those with NDRD superimposed on DGS. So, Renal biopsy should be performed in diabetics when the clinical scenario is atypical.