Background: A working group has defined five subtypes of focal segmental glomerulosclerosis (FSGS) based on light microscopic assessment (Columbia classification). Limited information is available on the prognostic and therapeutic implications of this classification in a European population. We conducted a retrospective analysis in 93 adult patients with biopsy-proven FSGS to determine the clinical features and outcome of FSGS variants.
Methods: Renal biopsy specimens of adult patients (>16 years) diagnosed with FSGS between 1980 and 2003 were reviewed according to the Columbia classification without the knowledge of clinical outcome. The medical records were reviewed for clinical data. Primary outcomes were remission rate and renal survival.
Results: The frequencies of the FSGS variants were: 32% NOS (FSGS not otherwise specified), 37% tip, 26% perihilar and 5% collapsing. Cellular FSGS was not found in the biopsies. The nephrotic syndrome was less frequent in FSGS NOS (57%) and perihilar FSGS (25%) compared to the tip variant (97%). Renal function was significantly better in patients with the tip variant compared to FSGS NOS (P<0.05). Glomerular sclerosis and hyalinosis was most severe in patients with perihilar FSGS, intermediate in FSGS NOS and the least severe in patients with the tip variant. Patients with perihilar FSGS were less likely to receive immunosuppressive medication. Renal survival at 5 years was significantly better for patients with the tip variant (78% for tip vs 63% and 55% for FSGS NOS and perihilar FSGS; P=0.02). Type of FSGS and serum creatinine concentration were independent predictors of renal survival. Remission rate was higher in patients with the tip variant (P=0.1).
Conclusion: The collapsing variant was rare in our population. Renal survival and remission rates were higher in patients with the tip variant. Use of the classification scheme for FSGS may be clinically useful.