ABSTRACT
To investigate the correlation of different types of urinary abnormalities or different proteinuria and hematuria with the pathological injury of kidney in IgA nephropathy with isolated hematuria and/or mild proteinuria. Methods: Patients with primary IgA nephropathy, isolated hematuria and/or mild proteinuria were enrolled in the Department of Nephrology, the Second Xiangya Hospital, Central South University from January 2013 to January 2018. According to the difference of red blood cell count in urinary sediment and quantitative of 24-hour urinary protein (24 h-UP) during renal biopsy, the patients were grouped in 3 ways: a simple hematuria group, a hematuria and proteinuria group, and a simple proteinuria group; a proteinuria I group, a proteinuria II group, and a proteinuria III group; a hematuria I group, a hematuria II group, and a hematuria III group. The clinical parameters such as age, mean arterial pressure, blood urea nitrogen, serum creatinine, blood uric acid, 24 h-UP, and renal pathological damage were compared. Results: A total of 157 patients met the inclusion criteria, including 71 males and 86 females. The most common pathological type was focal and/or segmental glomerulosclerosis. The Lee's classification were dominated by grade III and IV, and the renal pathological injury was heavy. Immunoglobulin deposition was dominated by simple IgA deposition. The most common fluorescence intensity of IgA deposition was +++. 97 (61.78%) patients were accompanied by complement deposition and were mainly composed of simple complement C3 deposition. There were 18 patients (11.47%) in the simple hematuria group, 111 patients (70.70%) in the hematuria and proteinuria group, and 28 patients (17.83%) in the simple proteinuria group. Compared with the simple hematuria group, the proportion of patients with mild injury was lower in the simple proteinuria group, and the proportion of patients with moderate-to-severe injuries was increased (χ2=7.053, P=0.008). Compared with the hematuria and proteinuria group, the proportion of patients with mild injury was lower in the simple proteinuria group, and the proportion of patients with moderate-to-severe injury was increased (χ2=4.294, P=0.038). Compared with the proteinuria I group, the proportion of patients with mild injury was lower in the proteinuria III group, and the proportion of patients with moderate-to-severe injury was increased (χ2=5.433, P=0.020). There was no significant difference in the proportion of patients with renal pathological injury among different hematuria groups (P>0.05). Conclusion: The clinical manifestations of patients with IgA nephropathy with hematuria and/or mild proteinuria are inconsistent with renal pathological damage. Some patients with mild clinical manifestations have severe renal pathological damage and the renal pathological damage is more serious in simple proteinuria. The more proteinuria, the heavier the renal pathological damage.