A prospective study on the impact of the renal biopsy in clinical management.

A three year prospective study involving 80 patients was conducted to assess the impact of renal biopsy on clinical management. Pre-biopsy predicted histologic diagnosis was changed in 35 (44%) of the patients as a result of the biopsy. Prognosis changed in 45 (57%) of the patients. Therapy changed in 25 (31%) of the patients. These results suggest that, overall, renal biopsy had a marked effect on management. However, we identified subgroups of patients who were unlikely to have their management changed as a result of the biopsy: of 16 patients with a pre-biopsy diagnosis of IgA nephropathy, 1 (6%) had treatment changed because of the biopsy; and of the 50 patients without heavy proteinuria (greater than 3 g/24 h), 10 (20%) had treatment changed because of the biopsy. Although our overall results suggest an important role for renal biopsy in clinical management, renal biopsy has the least apparent impact in patients with a pre-biopsy diagnosis of IgA nephropathy or without heavy proteinuria.