Renal outcomes in primary IgA nephropathy patients with segmental glomerular necrosis: a case-control study

The renal prognosis and treatment of primary IgA nephropathy (IgAN) patients with segmental glomerular necrosis (SGN) remain controversial. Patients with primary IgAN confirmed by renal biopsy were enrolled. Patients with SGN on renal biopsy were selected as the necrosis group, and a propensity score matching method was used to match a control group according to age, gender, weight, height and follow-up time. A total of 825 IgAN patients were enrolled in the present study. Seventy-three (8.8%) patients with SGN were selected as the necrosis group, and 292 patients without SGN were matched as the control group. Compared to the control group, a significantly increased serum fibrinogen level (3.97 g/L vs 3.54 g/L, P=.002) and proportion of patients with macroscopic hematuria (35.6% vs 14.7%, P<.001) was observed in the necrosis group. According to the new IgA pathological classification system, crescent formation was more pronounced in the necrosis group (P=.001). The average estimated glomerular filtration rate was obviously higher in the necrosis group and decreased more slowly during follow-up. However, the time-averaged urine protein-to-creatinine ratio remained low in the necrotic group, whereas it gradually increased in the control group. SGN suggests an active renal inflammatory state, but it was not an independent risk factor for a poor renal outcome in patients treated with immunosuppressive therapy. Furthermore, patients with SGN had a more stable renal function and low urinary protein excretion during follow-up, which may be attributable to aggressive immunotherapy.