Background: The goal was to study the role of serum IgA in patients with IgA nephropathy (IgAN) found during physical examination, and to explore its value in diagnosis, assessment of pathological injury, and clinical prediction of IgAN.
Methods: The study included 457 patients who were hospitalized between January 2010 and June 2018 due to physical abnormalities and diagnosed with kidney disease via renal biopsy. Renal histopathology was quantified according to Katafuchi semi-quantitative standards, while the IgAN patients were also scored according to Lee’s grading system.
Results: The average age of the 457 patients was 39.62 ± 13.52 years when abnormalities were found during physical examination. IgAN (202 cases, 46.12%) was the most common type of primary glomerulonephritis in the 457 patients. Of the IgAN patients, 75.25% (152 cases) were under 45 years old at the time of abnormal physical examination and IgAN patients were significantly younger than non-IgAN patients. There was a significant difference in the gender ratio between IgAN patients and non-IgAN patients (χ2 = 4.24, p = 0.039). In IgAN patients, the proportion of male patients, serum creatinine (SCr), the glomerular lesion and tubulointerstitial scores, and serum IgA were statistically higher than in non-IgAN patients with other types of primary glomerulonephritis; however, MDRD-GFR was lower. The ROC curve of serum IgA in the diagnosis of IgAN showed the AUC was 0.602. One hundred forty-seven cases (72.77%) were Lee’s III - V grade. The proportion of patients who were at Lee’s III - V grades in the normal serum IgA group (184 cases) was higher than that of the elevated serum IgA group (18 cases). There were no significant differences in gross hematuria, proteinuria, MDRD-GFR, SCr, and hypertension between the two groups.
Conclusions: Serum IgA may be of little value in the diagnosis of patients with IgA nephropathy detected via physical examination. The level of serum IgA may have predictive value in evaluating Lee’s pathological damage in IgAN patients.