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In 2019, the Nephrology Service of San Martín Hospital in La Plata, Buenos Aires began the prospective registry of patients undergoing renal biopsy (RB) with the aim of identifying demographics, clinical characteristics and reasons for indicating RB, as well as to understand its histopathological diagnoses.
Patients ≥15 years of age who underwent native kidney biopsy from March 01, 2019 to July 31, 2023 were included. Demographic and clinical variables were recorded. Blood, urine, immunological profile and viral serology tests were carried out. Indications for RB were defined: Nephrotic Syndrome (NS), Acute Nephritic Syndrome (ANS), Nephritic Nephrotic Syndrome (NNS), Rapidly Progressive Renal Injury (RPKI) and Proteinuria and Hematuria isolated or combined with acute kidney injury (AKI) or chronic kidney disease(CKD). The microscopy used and the number of glomeruli per sample were detailed. A descriptive analysis was made.
229 consecutive RB were carried out. DEMOGRAPHIC CHARACTERISTICS: Females 61.1%, average age 39.8 (standard deviation (SD) 16.4). 38 had second biopsies. 37.6% resided in La Plata, Berisso and Ensenada. 90.4% had Argentine nationality. 37.1% and 35.8% completed primary and secondary school, respectively. 45% were unemployed. CLINICAL FEATURES: Average body mass index 26.4 (SD 5.4); average Systolic and Diastolic Blood Pressure 126.8mmHg (SD 16.9) and 80.5mmHg (SD 11.8), respectively. 59.4% presented edema and 55% extrarenal symptoms. 79.5% showed one or more comorbidity. 85.6% received pharmacological treatment. RB INDICATIONS: Hematuria and proteinuria isolated or combined with AKI or CKD were 38.9%, NS 24%, ANS 14.4%, NNS 13.5% and RPKI 9.2%. Optical and immunofluorescence mycroscopy were used in 76.4% of cases and electron mycroscopy in 18.8%. Average glomeruli 19 (SD 10.9). FREQUENCY OF PATHOLOGIES: The definitive diagnoses were: Lupus Nephropathy (LN) 32.8%, Pauciimmune Glomerulonephritis/Antineutrophil Cytoplasmic Antibody-Associated Vasculitis (PIIGN/AAV) 12.2%, Membranous Nephropathy (MN) 10%, Minimal Change Disease (MCD) 9.2%, Immunoglobulin A Nephropathy (IGAN) 9.2%, Hypertensive Nephropathy (HTN) 7.4%, Focal and Segmental Glomerulosclerosis (FSGS) 6.6%, Diabetic Nephropathy (DN) 1.7%, miscellaneous 10.9%. SUBGROUP ≥65 YEARS OLD: Patients in this subgroup represented 10% of the sample, average age 70, 54% were males, NS was the most frequent indication for RB, with the most prevalent diagnoses being MN, AAV and NL.
This 51-month prospective study determined that the population served was mostly female, with an average age of 38, most residing in the interior of the Buenos Aires Province. The most frequent indication for RB was proteinuria and hematuria isolated or combined with AKI or CKD and the main diagnoses LN, PIIGN/AAV and MN. We highlight the usefulness of this work for improving quality of care in the diagnosis, treatment and monitoring of patients affected by glomerulopathies.