Kidney Outcome in Primary Focal Segmental Glomerulosclerosis (FSGS) by Using a Predictive Model

Introduction. Focal segmental glomerulosclerosis (FSGS) is one of the important causes of end stage kidney disease (ESKD). We evaluated the progression risk factors of primary FSGS to chronic kidney disease (CKD) or ESKD with a predictive model including clinical and histological predictors. Methods. 201 patients with primary FSGS (59% male, mean age: 38 ± 15 years), were studied. Time-dependent Cox model and C statistics were used for the predictive model. Interaction and correlation between independent variables were estimated. Results. During 55 ± 27 months of follow-up, 82 patients (41%) developed CKD (46) or ESKD (36) patients. In adjusted model, 1 unit of higher serum creatinine (SCr) at baseline (HR = 1.39, 95% CI: 1.15 to 1.70) and 1% increase in glomeruli with segmental glomerulosclerosis (SGS) (HR = 1.03, 95% CI: 1.02 to 1.04) or interstitial fibrosis/tubular atrophy (IF/TA) (HR = 1.03, 95% CI: 1.01 to 1.05) increased the risk of CKD/ESKD. In adjusted model, higher baseline proteinuria and collapsing variant were not associated with risk of CKD/ESKD. By adding SGS and IF/TA scores to baseline SCr in the model, discrimination by C statistics was 0.83 (95% CI: 0.77 to 0.90). Median renal survival was 3.1 years (95% CI: 2.2 to 4.1 years) in patients with highest risk score (baseline eGFR < 25 mL/min/1.73m2 + IF/TA/SGS > 50%), and 8.1 years (95% CI: 7.7 to 8.6 years).in those with lowest score (baseline eGFR > 75 mL/ min/1.73m2 + IF/TA/SGS < 5%). Conclusion. In primary FSGS, higher baseline SCr, increased SGS and IF/TA, but not baseline proteinuria and collapsing pathology, were the predictors for CKD/ESKD. These findings indicated the importance of timely detection and referral in prognosis of primary FSGS.