Daily low-dose prednisolone to prevent relapse of steroid-sensitive nephrotic syndrome in children with an upper respiratory tract infection: PREDNOS2 RCT
Authors: Christian Martin T , Webb Nicholas JA , Woolley Rebecca L , Afentou Nafsika , Mehta Samir , Frew Emma , Brettell Elizabeth A , Khan Adam R , Milford David V , Bockenhauer Detlef , Saleem Moin A , Hall Angela S , Koziell Ania , Maxwell Heather , Hegde Shivaram , Finlay Eric R , Gilbert Rodney D , Jones Caroline , McKeever Karl , Cook Wendy , Ives Natalie 
Published: January 2022

Background
Most children with steroid-sensitive nephrotic syndrome have relapses that are triggered by upper respiratory tract infections. Four small trials, mostly in children already taking maintenance corticosteroid in countries of different upper respiratory tract infection epidemiology, showed that giving daily low-dose prednisone/prednisolone for 5–7 days during an upper respiratory tract infection reduces the risk of relapse.

Objectives
To determine if these findings were replicated in a large UK population of children with relapsing steroid-sensitive nephrotic syndrome on different background medication or none.

Design
A randomised double-blind placebo-controlled trial, including a cost-effectiveness analysis.

Setting
A total of 122 UK paediatric departments, of which 91 recruited patients.

Participants
A total of 365 children with relapsing steroid-sensitive nephrotic syndrome (mean age 7.6 ± 3.5 years) were randomised (1 : 1) according to a minimisation algorithm based on background treatment. Eighty children completed 12 months of follow-up without an upper respiratory tract infection. Thirty-two children were withdrawn from the trial (14 prior to an upper respiratory tract infection), leaving a modified intention-to-treat analysis population of 271 children (134 and 137 children in the prednisolone and placebo arms, respectively).

Interventions
At the start of an upper respiratory tract infection, children received 6 days of prednisolone (15 mg/m2) or an equivalent dose of placebo.

Main outcome measures
The primary outcome was the incidence of first upper respiratory tract infection-related relapse following any upper respiratory tract infection over 12 months. The secondary outcomes were the overall rate of relapse, changes in background treatment, cumulative dose of prednisolone, rates of serious adverse events, incidence of corticosteroid adverse effects, change in Achenbach Child Behaviour Checklist score and quality of life. Analysis was by intention-to-treat principle. The cost-effectiveness analysis used trial data and a decision-analytic model to estimate quality-adjusted life-years and costs at 1 year, which were then extrapolated over 16 years.

Results
There were 384 upper respiratory tract infections and 82 upper respiratory tract infection-related relapses in the prednisolone arm, and 407 upper respiratory tract infections and 82 upper respiratory tract infection-related relapses in the placebo arm. The number of patients experiencing an upper respiratory tract infection-related relapse was 56 (42.7%) and 58 (44.3%) in the prednisolone and placebo arms, respectively (adjusted risk difference –0.024, 95% confidence interval –0.14 to 0.09; p = 0.70). There was no evidence that the treatment effect differed when data were analysed according to background treatment. There were no significant differences in secondary outcomes between treatment arms. Giving daily prednisolone at the time of an upper respiratory tract infection was associated with increased quality-adjusted life-years (0.9427 vs. 0.9424) and decreased average costs (£252 vs. £254), when compared with standard care. The cost saving was driven by background therapy and hospitalisations after relapse. The finding was robust to sensitivity analysis.

Limitations
A larger number of children than expected did not have an upper respiratory tract infection and the sample size attrition rate was adjusted accordingly during the trial.

Conclusions
The clinical analysis indicated that giving 6 days of daily low-dose prednisolone at the time of an upper respiratory tract infection does not reduce the risk of relapse of steroid-sensitive nephrotic syndrome in UK children. However, there was an economic benefit from costs associated with background therapy and relapse, and the health-related quality-of-life impact of having a relapse.

Future work
Further work is needed to investigate the clinical and health economic impact of relapses, interethnic differences in treatment response, the effect of different corticosteroid regimens in treating relapses, and the pathogenesis of individual viral infections and their effect on steroid-sensitive nephrotic syndrome.

Trial registration
Current Controlled Trials ISRCTN10900733 and EudraCT 2012-003476-39.

Funding
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 3. See the NIHR Journals Library website for further project information.