Clinical and histopathological features related to time to complete remission in adult-onset minimal change nephrotic syndrome patients with corticosteroid treatment

Background Minimal change nephrotic syndrome (MCNS) is a common type of nephrotic syndrome in adults, though evidence regarding its clinical and histopathological features related to time to complete remission (CR) is limited. Methods This was a retrospective study of biopsy-proven, first-onset, adult MCNS patients who achieved CR after undergoing corticosteroid treatment. Body weight (BW) change rate was calculated as follows: (BW at admission - BW at discharge)/BW at discharge x 100. Histopathological examinations were performed, with particular attention given to tubulointerstitial lesions. Results Fifty-seven patients (median 41 years old, range 22-63 years; 37 males) were diagnosed with MCNS from 2007 to 2020. Time to CR was a median 11 (8-21) days. In addition to serum creatinine and urinary protein, BW change rate also showed a positive correlation with time to CR (r(s) = 0.438, p < 0.001; r(s) = 0.280, p = 0.035; r(s) = 0.544, p < 0.001; respectively), while multivariate Cox proportional hazards models also revealed those factors as significant predictors for longer time to CR. In MCNS patients with a higher BW change rate (n = 28), serum creatinine, urinary protein, histopathological score, and time to CR were significantly greater as compared to those with a lower BW change rate (n =29). Also, in those patients, histopathological interstitial edema was significantly associated with longer time to CR after adjustments for serum creatinine and urinary protein. Conclusion The present results indicate that BW change rate can predict time to CR in adult-onset MCNS patients. Histopathologically, interstitial edema is also an important factor for time to CR in MCNS patients with greater BW increase.