P0437IS RENAL BIOPSY NEEDED FOR THE DIAGNOSIS OF NEPHROPATHIES OR IT IS SUFFICIENT WITH A CLINICAL DIAGNOSIS?
Authors: Calle Garcia Leonardo , Rodriguez Gomez Astrid , Heras Benito Manuel , Urzola Rodriguez Giomar , Fernandez-Reyes Luis Maria Jose 
Published: June 2020

Abstract

Background and Aims
Percutaneous renal biopsy (PRB) guided by ultrasound is the gold standard for the diagnosis of nephropathies and glomerulopathies. Sometimes, comorbidity and relative contraindications for PRB could condition us to consider clinical diagnosis as sufficient to treat renal pathology. This is a continuous challenge for the nephrologist due to the prognostic and therapeutic diversity of the different types of nephropathies. Therefore, we wonder if in most cases it is still necessary to perform PRB, or clinical diagnosis would be enough in a significant number of them. We decided to assess our PRB series over 15 years, comparing clinical and biopsy diagnosis, and learning about the complications associated with the technique.

Method
Cross-sectional analysis of the 262 PRB conducted between January 2003 and December 2018. In our department, before performing the PRB, doctors always make a clinical report with different diagnostic possibilities that facilitates the pathologist's work. For this study the first diagnostic option, being the most clinically compatible with the patient, was always taken. We also collected socio-demographic data, clinical data (hypertension and diabetes mellitus), pre and post-biopsy diagnosis, and complications associated with the technique. For the statistical analysis, the SPSS 15 program was used to calculate frequencies, and the Kappa coefficient for diagnostic concordance.

Results
262 PRB were performed, of which 149 (56.9%) were performed in men and 113 (43.1%) in women. Average age: 58.6 ± 19.2 years. 173 patients were hypertensive (66%) and 50 had DM (19.1%). Renal pathologies by age are similar to the data reported by Spanish Society. The table shows the concordance measured by the kappa coefficient in the pre and post-PRB diagnosis of the most frequent nephropathies. There were 15 PRB with complications (5.8%): 12 minors (4.6%, haematuria and hematoma); and 3 major: 2 haemorrhages (0.8%) and 1 nephrectomy (0.4%). 33 PRB (12.6%) were inconclusive due to insufficient material.

Conclusion
From the data obtained, a high mismatch was observed in very common nephropathies in our environment, such as IgA nephropath and pauci-immune focal and segmental necrotizing glomerulonephritis. In contrast, PRB showed more cases of diabetic nephropathy and tubulointerstitial nephropathy. In the case of the pathologies due to nephrotic syndrome (table) we find a high discordance. This may be due to the fact that in all of those cases there was an initial nephrotic syndrome, and our clinical diagnosis was partly based on the frequency of glomerulopathies in the adult. In conclusion, the different concordances between pre and post-biopsy diagnoses show us that clinical diagnosis is not enough to obtain a final diagnosis. In most cases PRB is necessary for the definitive diagnosis. In addition, after the introduction of the ultrasound, complications have decreased, especially when the biopsy is performed by the nephrologist.