Abstract
Background and Aims
In the treatment of idiopathic focal segmental glomerulosclerosis (FSGS) with nephrotic syndrome, the remission of proteinuria is considered to be an important goal. The partial remission of proteinuria improves renal survival, whereas it may progressively reduce the renal function. A study searched for a novel partial remission more accurately reflecting the long-term renal outcome. The goal of proteinuria reduction for improving the renal prognosis remains to be clarified.
We examined factors associated with the long-term renal outcome of idiopathic FSGS.
Method
Of 148 patients with FSGS diagnosed based on kidney biopsy between 1981 and 2018, a retrospective cohort study was conducted involving 33 who had undergone immunosuppressive therapy for nephrotic syndrome, and had been followed-up for ≥1 year, excluding those with secondary FSGS. We examined the renal prognosis, regarding a 50% decrease in the estimated glomerular filtration rate (eGFR) as an outcome. We calculated the rate of decrease in the urinary protein level 4 and 8 months after the start of treatment, and estimated the rate of decrease associated with renal hypofunction using ROC analysis. Based on the results of ROC analysis, Cox’s proportional hazard analysis was performed using factors contributing to renal hypofunction as covariates.
Results
Concerning the background of the 33 patients, the mean follow-up period was 11.4 years, and there were 24 males. The mean age was 49.8 years, and the mean blood pressure was 100.5 mmHg. The mean urinary protein level, albumin (Alb) level, eGFR, and total cholesterol (TCho) level were 7.4 g/day, 2.1 g/dL, 44.3 mL/min/1.73 m2, and 369 mg/dL, respectively. Corticosteroid therapy was selected in 21 patients, whereas it was combined with steroid pulse therapy in 12. The daily dose of prednisolone was 37.3 mg.
On ROC analysis, the rate of decrease in the urinary protein level after 4 months was 83.1% (AUC: 0.74, sensitivity: 0.80, specificity: 0.74), and that after 8 months was 85.7% (AUC: 0.78, sensitivity: 0.90, specificity: 0.65).
Cox’s proportional hazard analysis, in which the data were adjusted with the sex, blood pressure, urinary protein level at the start of treatment, Alb level, eGFR, and treatment methods, showed that the rate of decrease in the urinary protein level after 4 months was significantly correlated with renal hypofunction: after 4 months: hazard ratio, 0.19 (95%CI: 0.04-0.77); p=0.0202; after 8 months: hazard ratio, 0.34 (95%CI: 0.05-1.37); p=0.1359.
Conclusion
In the treatment of idiopathic FSGS with nephrotic syndrome, the rate of decrease in the urinary protein level 4 months after the start of treatment was correlated with the long-term renal outcome.
Henoch-Schönlein Nephritis Manifesting with Purpura 15 years after Diagnosis of IgA Nephropathy
