William Morello1, Federica Alessandra Vianello1, Emanuele Proverbio1, Giovanni Montini2. 1. Pediatric Nephrology, Dialysis and Transplant Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Di Milano, via Commenda 9, 20122, Milano, Italy. 2. Pediatric Nephrology, Dialysis and Transplant Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Di Milano, via Commenda 9, 20122, Milano, Italy. giovanni.montini@unimi.it.
Dear Editors,We thank Dr. Krishnasamy and co-authors for their letter highlighting their experience with COVID-19 in India [1] in response to our review and recommendations on the management of idiopathic nephrotic syndrome (INS) during the pandemic [2]. As the authors stated, this publication only became available after our systematic search of the literature was performed and therefore it was not included in the review.In their paper [1], which reported retrospectively collected data from 4 pediatric nephrology centers in New Delhi, the authors describe a mortality rate of 4.5% in children with INS and SARS-CoV-2 infection (2/44), and they identify a concomitant relapse as a predictor of a worse outcome. Their findings are very different from the data summarized in our review [2] and the results of a new search performed on 30 November 2021, including the first collaborative European report and a national study performed by the Italian Society of Paediatric Nephrology.There is only 1 other collaborative study reporting a similar mortality rate (3.5%) in paediatric patients affected by kidney diseases and SARS-CoV-2 infection [3], but the underlying clinical condition of the fatal cases is not specified (INS vs. other kidney diseases). Interestingly, all deaths were in developing countries, with 3 out of 4 in India.The unexpected dismal outcome of INS patients reported by Krishnasamy et al. may be related to a distinct genetic background, which is believed to influence the course of SARS-CoV-2 infection, or a different approach to INS relapses and COVID-19 themselves. Therefore, it will be crucial to understand if similar complications will be reported in the near future by others, and how this mortality rate compares to that expected for children with SARS-CoV-2 infection or those with INS relapses in India.However, according to the available literature, it is still correct to affirm that the course of SARS-CoV-2 infection is mostly mild in children with INS, even during relapses.SARS-CoV-2 infection may be complicated by acute kidney injury or tubular damage, in children with and without underlying kidney conditions. Indeed, our recommendations suggest monitoring SARS-CoV-2 infection for signs of relapse in children with INS and support SARS-CoV-2 vaccination in this population. Moreover, we recommend considering hospital admission in the case of clinical worsening [2].On this basis, we believe our recommendations are still effective and helpful for the management of children with INS during the pandemic.