Primary FSGS in Nephrotic Adults: Clinical Profile, Response to Immunosuppression and Outcome

Primary focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic proteinuria in adults. Most studies on FSGS have combined pediatric and adult patients. This study aims at assessing the response to immunosuppression and its impact on renal survival in adults with primary FSGS.

Patients with nephrotic proteinuria with primary FSGS seen from January 2010 to December 2014 were included. Clinical, laboratory and treatment details were recorded. Deterioration in renal function was defined as ≥50% decline in estimated glomerular filtration rate (eGFR) or progression to end-stage renal disease.

There were 116 patients with median follow-up of 23.6 (6-65.1) months. Baseline proteinuria was 5.1 ± 2.6 g/day and eGFR was 96.9 ± 35.1 ml/min/1.73 m2. One hundred one (94.4%) patients had received angiotensin converting enzyme inhibitor/angiotensin receptor blocker (ACEi/ARB). One hundred fourteen patients received steroids. Forty two of 114 patients (36.8%)were steroid resistant. Thirty eight received calcineurin inhibitors (CNI). Seventeen (44.7%) were CNI resistant of which 2 achieved remission with alternate immunosuppression. Eleven (9.5%) patients had worsening renal function - 9 had no remission, 2 had PR with none in CR (30 vs. 5.6% vs. 0, respectively, log-rank, p < 0.001). ACEi/ARBs use and remission of proteinuria were independently associated with better renal survival.

Achieving remission, whether complete or partial, is the critical factor in predicting renal survival in nephrotic adults with primary FSGS. Steroid-resistant patients have reasonable renal survival, if proteinuria is reduced with timely use of alternate immunosuppression. CNI resistance is a major hurdle in management with limited treatment options.