Investigation of clinicopathological features and prognostic factors in children with biopsy diagnosis of IgA Nephropathy and IgA Vasculitis (Henoch-Schönlein purpura) nephritis

Immunoglobulin A (IgA) nephropathy (IgAN) and IgA vasculitis (IgAV) nephritis (IgAVN) are prevalent glomerulopathies in the pediatric population. They may present with a variable clinical course ranging from isolated microscopic hematuria to rapidly progressive glomerulonephritis. Both diseases typically progress slowly in children and some patients end up with the end-stage renal disease in adulthood. To predict the prognosis of IgAN patients studies have been carried out that tried computer-based prognosis estimation algorithms. This study was conducted to evaluate the clinicopathological and prognostic features of IgAN and IgAVN patients followed at Hacettepe University Department of Pediatric Nephrology. Patients with biopsy proven IgAN and IgAVN with at least 6 months of follow-up between January 2005 and December 2021 were included in the study. Demographics, clinical, laboratory, and biopsy findings were recorded from hospital files. Fifty-two percent of 27 IgAN patients included in the study were male and the median age of diagnosis was 12 years. Fifty-four percent of 48 IgAVN patients were male and the median age of diagnosis was 8 years. Complete remission was seen in 23 (85%) IgAN patients after a median follow-up of 40 months and 43 (90%) IgAVN patients at a median follow-up of 35.5 months. Only one patient with IgAN (3.7%) had end-stage renal disease at last follow-up. Computer-based prognosis prediction algorithm (QxMD) found a high risk of eGFR decline for 5 out of 18 patients with IgAVN and 5 years of follow-up, and a genuine eGFR decline was observed in two of these patients. Whereas in 6 IgAN patients with 5-year follow-up, the risk was calculated to be low and genuine eGFR decline was observed among none of them. While low serum albumin level (p=0.011), severe proteinuria (p=0.032) at diagnosis, and duration to achieve remission (p=0.035) were associated with poor prognosis in IgAN, in IgAVN, duration to achieve remission (p=0.001), segmental glomerulosclerosis (p=0.009) and presence of crescents in biopsy (p=0.034) were related to poor prognosis. When IgAN and IgAVN patients were compared, in patients IgAVN; age at diagnosis was found to be younger (p=0.002), nephrotic proteinuria at diagnosis more common (p=0.001), serum albumin levels lower (p<0.001), crescents in biopsy (p=0.017) and immunosuppressive treatment used (p=0.014) more frequent. In conclusion, although IgAN and IgAVN have similar pathophysiological features they also differ in important clinical and prognostic aspects. There is still a need for prospective, large scaled, multicentric studies using computer-based prognosis prediction algorithms to estimate prognosis and make treatment strategies based on risk scoring in childhood IgAN and IgAVN.