Clinical course & management of childhood nephrotic syndrome in Germany: a large epidemiological ESPED study.

BACKGROUND: Nephrotic syndrome (NS) is one of the most frequent occurring chronic kidney diseases in childhood, despite its rarely occurrence in the general population. Detailed information about clinical data of NS (e.g. average length of stay, complications) as well as of secondary nephrotic syndrome (SNS) is not well known.

METHODS: A nationwide ESPED follow-up study presenting the clinical course and management of children with NS in Germany.

RESULTS: In course of 2 years, 347 children developed the first onset of NS, hereof 326 patients (93.9%) had a primary NS, and 19 patients had a SNS (missing data in 2 cases), the majority due to a Henoch-Schönlein Purpura. Patients with steroid-resistant NS (SRNS) stayed significantly longer in hospital than children with steroid-sensitive NS (25.2 vs. 13.3 d, p <  0.001). Patients with bacterial/viral infections stayed longer in hospital (24.9 d/19.5d) than children without an infection (14.2 d/14.9 d; p <  0.001; p = 0.016). Additionally, children with urinary tract infections (UTI) (p < 0,001), arterial hypertension (AH) (p < 0.001) and acute renal failure (ARF) (p < 0,001) stayed significantly longer in hospital. Patients with SRNS had frequent complications (p = 0.004), such as bacterial infections (p = 0.013), AH (p < 0.001), UTI (p < 0.001) and ARF (p = 0.007). Children with a focal segmental glomerulosclerosis (FSGS) had significantly more complications (p = 0.04); specifically bacterial infections (p = 0.01), UTI (p = 0.003) and AH (p < 0,001). Steroid-resistance was more common in patients with UTI (p < 0.001) and in patients with ARF (p = 0.007). Furthermore, steroid-resistance (p < 0.001) and FSGS (p < 0.001) were more common in patients with AH.

CONCLUSIONS: This nationwide, largest German study presents results on the clinical course of children with NS considering a diverse range of complications that can occur with NS. The establishment of a region-wide and international pediatric NS register would be useful to conduct further diagnostic and therapy studies with the aim to reduce the complication rate and to improve the prognosis of NS, and to compare the data with international cohorts.