Impact of initial steroid response on transplant outcomes in children with steroid-resistant nephrotic syndrome

Background Limited data suggest children with secondary steroid-resistant nephrotic syndrome (secondary SRNS) have increased risk of recurrence post transplantation. There are no data on the association between secondary steroid resistance and risk of transplant loss. Methods Children who received kidney transplantation between 2000 and 2019 for either primary or secondary SRNS in Australia and New Zealand were included. Children presenting with nephrotic syndrome before 12 months were excluded. Data were gathered from chart reviews and ANZDATA. Transplant survival was estimated using the Kaplan-Meier estimator with Cox modelling used to explore predictors of survival. Results There were seventy children, 38 (55%) male, median age at presentation 4 years (IQR 2-7) and 46 (66%) Caucasian. Median age at transplant was 11 years (IQR 7-15) and 39 (55%) received living donor transplant. Secondary SRNS occurred in 20/70 (29%). For those with secondary SRNS, 18/20 (90%) had recurrence post-transplant, compared to 18/50 (36%) with primary SRNS (p = 0.001). Every child with history of atopy (n =11) or with hypoalbuminaemia at time of transplant (n= 13) experienced immediate recurrence. For children with secondary SRNS, 8/18 (44%) with post-transplant recurrence had no response to therapy. For children with primary SRNS, 4/18 (22%) with recurrence had no response to therapy (p = 0.3). Overall, 10-year transplant survival was 47% (95%CI 29-77%) for those with secondary SRNS, compared to 71 (95%CI 57-88%) for those with primary SRNS (p = 0.05). Conclusions Secondary steroid resistance is strongly associated with SRNS recurrence. Atopy and hypoalbuminaemia at transplant may be novel risk factors for recurrence. Further research is needed to assess if secondary steroid resistance is associated with poorer transplant outcomes.