Long-term renal survival and related risk factors for primary membranous nephropathy in Chinese children: a retrospective analysis of 217 cases.

BACKGROUND

Primary membranous nephropathy (PMN) is a rare pathological finding in paediatric patients. Data on PMN in children have been restricted to studies with small samples and fairly short follow-up periods. Therefore, we conducted this single-centre study to evaluate the long-term renal survival and related risk factors for PMN in children, and the clinical and histological characteristics were also described.

METHOD: Two hundred and seventeen children with PMN were enrolled from July 2008 to September 2017. Patients with follow-up durations < 12 months were excluded, except for patients who progressed to end-stage kidney disease (ESKD) or experienced a related death within 12 months. Long-term renal survival and related risk factors were analysed.

RESULT: The sex ratio was 1.33:1 (male vs female), and the median age was 15.0 (14.0-17.0) years old. The most prominent clinical manifestation was nephrotic syndrome (130 59.9%), which was accompanied by various degrees of oedema (142 65.4%), hyperlipidaemia (151 69.6%), hypoalbuminemia (130 59.9%), and nephrotic proteinuria (135 62.2%). Hypertension occurred in 36.4% of children with PMN. After a median follow-up of 45.0 (23.5-74.0) months, 11 patients (5.1%) developed ESKD, and the cumulative kidney survival rates of ESKD at 5 and 10 years after renal biopsy were 95.3% and 67.8%, respectively. The cumulative kidney survival rates of the combined event of ESKD and/or 30% decline in estimated glomerular filtration rate (eGFR) at 5 and 10 years after renal biopsy were 92.6% and 59.5%, respectively. Cox multivariate regression and Kaplan-Meier analysis demonstrated that hypertension and proteinuria ≥ 50 mg/kg/day were associated with renal outcome.

CONCLUSION

In this study, the 5-year and 10-year cumulative renal survival rates of ESKD in children with PMN were reported for the first time as 95.3% and 67.8%, respectively. In addition, this is the first report to find that hypertension and proteinuria  ≥ 50 mg/kg/day are associated with renal outcome in children with PMN.