NephroS: Phenotypical Analysis of a Large National Nephrotic Syndrome Cohort: A Multicentre Longitudinal Study From Great Britain

ABSTRACT

Background: Nephrotic Syndrome (NS) is a rare kidney disease diagnosed by the presence of proteinuria, oedema and hypoalbuminemia. The estimated global incidence of NS is 2-7 people per 100,000. The pathological processes that cause NS remain elusive. This novel multicentre longitudinal study aimed to identify the clinical and socio-demographic characteristics of a large NS cohort across Great Britain. Phenotypical analysis of such a large cohort will help understand the natural history and patterns of disease during a patient's lifetime. Method(s) A large multicentre longitudinal study was set up in January 2010 in 51 adult and paediatric sites across England, Scotland and Wales. Detailed prospective and retrospective clinical data was captured onto the Rare Renal Diseases Registry (RaDaR) over a period of 12 years from date of diagnosis until the cut-off point in January 2022. Patients were categorised by both their response to steroids and histological diagnoses to identify specific NS subgroups. Result(s) Over 12 years, a total of 1974 adult and paediatric NS patients were recruited. The results show that NS is a male predominant condition (56%) and more prevalent in South Asian (13%) and African ethnicities (4%). A large proportion of patients were steroid-sensitive (48%), and the main histological diagnosis was Minimal Change Disease (MCD) (50%). Those who reached end stage renal disease (16%) were mainly aged 0 - 17 years old. A high proportion of deaths were noted in 2020/1, and caused by cancer or COVID-19. Conclusion(s) It can be concluded that NS is dominant in males, and in South Asian and African ethnicities. A large proportion of patients were steroid-sensitive, and the main histological diagnosis was MCD. The data gathered in this study will help transform our understanding of NS. To better understand the implications of these results, future research including international collaboration will facilitate the development of translational research and evidence-based recommendations.