Renal biopsy in chronic kidney disease: lessons from a large Italian registry.

Background: Renal biopsy procedure in patients with chronic renal failure (CRF) may represent a valid tool to help clinicians in clinical practice. However, the use of this invasive method in CRF is variable and it reflects the hospital biopsy policy.

Methods: To better define the CRF-related histological patterns and to assess the clinical utility of this procedure in this extensive group, we analyzed biopsy records of 1,185 CRF patients living in a large area of north-east Italy from 1998 to 2010.

Results: Data analysis showed that, although the biopsy incidence rate and the histological features were unchanged, the mean age of our CRF patients increased during the study period (R(2) = 0.42, p < 0.01). Primary and secondary glomerulonephritis (SGNs) were the main histological presentations (53.9 and 23%, respectively). SGNs were over-diagnosed in females. Leading histological types were immunoglobulin A nephropathy (22%), focal segmental glomerulosclerosis (12.4%), membranous glomerulonephritis (MGN, 7.5%) and nephroangiosclerosis (7.3%). These forms were also highly frequent in CRF patients with elevated proteinuria and moderate/severe renal damage. Elderly patients were primarily affected by MGN. After biopsy, 49.5% of CRF patients with and 34.1% without nephrotic syndrome received immunosuppression therapy.

Conclusions: This study demonstrated that renal biopsy in CRF patients, regardless of age and glomerular filtration rates, is safe and essential to achieve a correct diagnosis and to commence the correct therapy. Additionally, it revealed that, even in patients with severe renal damage, it is possible to perform an accurate histological diagnosis and, interestingly, end-stage kidney disease seems not to be the primary form.