#5506 native kidney biopsy: a national survey on, diagnoses and outcomes

Abstract Background and Aims Since 2014, all adult native kidney biopsies undertaken in Scotland have been recorded by the Scottish Renal Registry (SRR). We aimed to report current data on indications for kidney biopsy, and outcomes following biopsy including requirement for kidney replacement therapy (KRT) and mortality. Method All 9 adult nephrology centres covering a population of over 5 million people report complete data on all kidney biopsies undertaken to the SRR. This includes indication, age, gender and diagnosis. The SRR collects requirement for KRT and death. Death or KRT at 6 months, 1 year and 2 years from date of first native kidney biopsy in patients with IgAN, MGN or ATIN were recorded. Results 5095 native kidney biopsies undertaken in 4702 patients between 01/01/2014 and 31/12/2021 were included. This averages 117.1 biopsies per million population / year. 54.7% were male with mean age 57.2 (SD 17.2) years. 98.2% of kidney biopsies were deemed adequate for diagnosis. Data completeness is over 99%. The commonest indications for native kidney biopsy were acute kidney injury query cause (AKI - 30.0%), chronically reduced eGFR (CKD) (28.1%) and nephrotic syndrome (19.7%). Overall, the commonest diagnoses made were: IgA nephropathy (IgAN 13.1%), tubulointerstitial nephritis (ATIN 8.5%) and membranous nephropathy (MGN 7.2%). Table 1 shows diagnoses made by biopsy indication. Conclusion In a complete national dataset, AKI is the commonest indication for native kidney biopsy and most commonly leads to a diagnosis of ATIN. IgAN remains the commonest primary glomerulopathy diagnosed on kidney biopsy, with MGN being the most likely diagnosis in patients biopsied for indication of nephrotic syndrome. Kidney and patient survival varies at 2 years depending on diagnosis. Table 2 shows that at 2 years the cmortality rate (Fig. 1) is highest in patients with MGN (11.4%) and risk of KRT highest in patients with IgAN (10.2%).