6930 TOO ELDERLY FOR A KIDNEY BIOPSY?

Abstract Background and Aims As we age, we lose kidney function and accumulate risk factors and comorbidities that predispose to kidney damage. However, kidney disease can develop at any time. Life expectancy continues to improve worldwide. For that reason, more elderly patients are undergoing diagnostic kidney biopsies (KB). There is a general reluctance in performing KB in those patients. It is important to know if a diagnosis KB in elderly patients can have a positive therapeutic impact. Method In this retrospective cohort study, we analyzed the medical charts of all patients aged ≥ 80years who underwent a native kidney biopsy (KB) between January and December 2021, in a central hospital in Portugal. Results Between January and December 2021, 59 patients underwent a native KB, 6 of them over 80 years of age (10% of all patients). Between those elderly patients, the median age was 82 years. The indications for KB were chronic kidney disease with a nephrotic range proteinuria in 3 patients, nephrotic syndrome, acute glomerulonephritis and acute kidney injury in 1 patient each. Median serum creatinine was 2.27 mg/dL (minimum 0.8 and maximum 5.4 mg/dL) and median protein-to-creatinine ratio was 5.7g/g (minimum 3.3 and maximum 13g/g). The pathological diagnoses found were focal and segmental glomerulosclerosis (FSGS) (n=2), pauci-immune crescentic glomerulonephritis (n=1), membranous nephropathy in a patient with a follicular lymphoma (n=1), acute interstitial nephritis (AIN) (n=1), and diabetic glomerulosclerosis in a patient with a monoclonal gammopathy of undetermined significance (n=1). 3 patients have received a kidney-specific treatment – the patient with AIN started corticosteroids, one patient with FSGS was submitted to corticosteroids plus tacrolimus, and the patient with pauci-imune crescentic glomerulonephritis to corticosteroids plus rituximab. The patient with membranous nephropathy and follicular lymphoma received a specific chemotherapy regimen according with lymphoproliferative disease. An improvement in kidney function occurred only in one patient and the other three developed adverse effects (particularly corticosteroids induced diabetes and infections). One year later, one of patients who received treatment was dead, another one was on hemodialysis, and the other two patients had a glomerular filtration rate lower than 15mL/min/1.73 m2. Conclusion Elderly patients have a higher risk of adverse effects from the kidney-specific treatment. It