Clinical features, pathological characteristics, and prognosis of patients with IgA nephropathy complicated with nephrotic syndrome

Nephrotic syndrome (NS) occurs in 5-15% of patients with IgA nephropathy (IgAN), resulting in poorer long-term outcomes compared to those without NS. Clinical features and renal prognosis for patients with both NS and IgAN across different kidney pathologies have not been fully elucidated. This study included patients with primary IgAN through renal biopsy at the First Affiliated Hospital of Sun Yat-sen University from January 2001 to November 2021 presenting with NS. Renal endpoint was defined as a 50% decrease in estimated glomerular filtration rate or progression to end-stage renal disease. A total of 207 patients with IgAN and NS were categorized into four pathological groups: IgAN with mesangial proliferative glomerulonephritis (IgAN-MsPGN) (n = 150), IgAN with minimal change disease (IgAN-MCD) (n = 49), IgAN with membranous nephropathy (IgAN-MN) (n = 7), and IgAN with membranoproliferative glomerulonephritis (IgAN-MPGN) (n = 1). Compared to the IgAN-MsPGN group, the IgAN-MCD group consisted of more males, had a younger average age, lower blood pressure, a lower prevalence of hematuria, and lower serum albumin and creatinine levels, whereas the IgAN-MN group was characterized by an older average age and lower serum creatinine levels. The IgAN-MCD group exhibited the mildest pathological changes among the groups. Of all patients, 133 were followed for an average follow-up period of 52.07 ± 44.04 months. Thirty-seven patients (27.8%) reached the renal endpoint. The IgAN-MCD group showed a higher rate of proteinuria remission and a better renal prognosis than the IgAN-MsPGN group. In conclusions, significant differences in clinicopathological features and long-term prognosis were observed among NS-IgAN patients with varying pathological phenotypes.