Supplementary Material for: Spectrum of non-diabetic kidney diseases in patients with type 2 DM who underwent kidney biopsy in Egypt

Introduction: Diabetic kidney disease (DKD) affects 30-40% of diabetic patients. The prevalence of non-diabetic kidney disease (NDKD) in patients with type 2 DM (T2D) in Egypt is unknown. This study aimed to assess the prevalence of NDKD in patients with T2D in Egypt. Methods: In this cross-sectional study, we searched the data of patients with T2D who underwent a native kidney biopsy between January 2010 and December 2020 in a kidney pathology laboratory in Egypt. Results: Of 12,006 patients who underwent kidney biopsy, 677 patients had T2D. NDKD was found in 285 patients (42.7%), DKD in 220 patients (33%), and mixed DKD and NDKD in 162 patients (24.3%). The total prevalence of NDKD was 67% in patients with T2D in our study group. Membranous nephropathy (MN) was the most common histopathological disease in patients with NDKD (20.6%) followed by acute tubular injury (ATI) (19.2%) and focal segmental glomerulosclerosis (FSGS) (15.2%). The presence of ATI in kidney biopsy was associated with a significantly higher mean serum creatine level (P<0.001). Minimal change disease was associated with significantly higher proteinuria level (P>0.001). In multivariate analysis, the duration of diabetes was a significant predictor of NDKD, with longer duration decreasing the likelihood of the 'NDKD' outcome. Conclusion: NDKD is prevalent among patients with T2D. Kidney biopsy remains the gold standard for diagnosing NDKD in patients with T2D.