Abstract: Objective　To analyze the clinical data, pathological characteristics and prognosis of IgA nephropathy patients with microalbuminuria and renal insufficiency. Methods　A total of 162 patients with primary IgA nephropathy diagnosed by percutaneous renal biopsy and 24 hour urinary protein quantification (≤0.5 g) were selected. They were divided into the normal renal function group (n=107, the serum creatinine ≤115 μmol/L) and the renal insufficiency group (n=55, the serum creatinine > 115 μmol/L) according to their creatinine values. The clinicopathological data of patients hospitalized with renal puncture biopsy were collected, and the clinical and pathological characteristics and prognosis were analyzed between the two groups. The survival curve was plotted by Kaplan-Meier method to compare the difference in renal survival rate between the two groups. Cox proportional risk model was used to analyze the risk factors of end-point events in IgA nephropathy patients with microalbuminuria. Results　Compared with the normal renal function group, the proportion of male patients and proportion of patients with hypertension, age, albumin, serum creatinine, serum uric acid, triglyceride, neutrophils and potassium levels were higher in the renal insufficiency group, and the levels of hemoglobin and platelets were lower (P＜0.05). Patients in the renal insufficiency group showed more segmental sclerosis synechia (S1) of the glomerulus, higher proportion of renal tubular atrophy or (and) renal interstitial fibrosis (T1/T2) and crescents (C1/C2), and higher proportion of glomerular ischemia sclerosis, glomerular segmental sclerosis, cell/fibrous crescents, and heavier arteriole injury (P＜0.05). The results of survival analysis showed that the cumulative renal survival rate was lower in patients with renal insufficiency than that of patients with normal renal function (Log-rank χ2=24.960，P＜0.01). Multivariate Cox proportional risk model analysis showed that the increased serum creatinine, decreased hemoglobin and small arterial injury were independent risk factors for end-point events in patients with microproteinuria combined with renal insufficiency (P＜0.05). Conclusion　The clinical and pathological changes of microproteinuria combined with renal insufficiency are more severe and the prognosis is worse than those of IgA nephropathy with microproteinuria alone.

Key words: glomerulonephritis, IgA, renal insufficiency, proteinuria, prognosis, microalbuminuria