Objective To investigate the relationship between systemic immune inflammatory index (SII) and hypoalbuminemia in patients with immunoglobulin A nephropathy (IgAN).

Methods A total of 143 patients with IgAN were selected as study objects. According to whether serum albumin was more than 35 g/L or not, the patients were divided into hypoalbuminemia group and normal group. The SII level (SII=platelet×neutrophils/lymphocytes) and clinical data of the two groups were compared. According to the median SII, these 143 patients were divided into low SII group and high SII group, and clinical data of the two groups were compared. Logistic regression analysis was used to explore the risk factors of hypoproteinemia in patients with IgAN, and Spearman correlation analysis was used to analyze the correlations of related indexes with serum albumin.

Results There were 35 of 143 patients with hypoproteinemia (24.48%). Age, proportion of patients with pathological classification of E1, leukocyte, neutrophil, platelet, total cholesterol, 24-hour urinary protein quantity (24 hUTP), low density lipoprotein, SII, platelet to lymphocyte ratio (PLR) and neutrophil to lymphocyte ratio (NLR) in the hypoproteinemia group were higher than those in the normal group, while the levels of hemoglobin, albumin and estimated glomerular filtration rate (eGFR) were lower than those in the normal group, and the differences were statistically significant (P < 0.05). Age, levels of leukocyte, neutrophils, platelets, 24 hUTP, total cholesterol, PLR and NLR in the high SII group were higher than those in the low SII group, albumin, eGFR level and the proportions of patients with pathological type of T0 were lower than those in the low SII group, and the proportion of patients with pathological types of E1 and T1 to T2 was higher than that in the low SII group(P < 0.05). The results of correlation analysis showed that serum albumin was negatively correlated with SII, PLR, and neutrophils (P < 0.05), and positively correlated with creatinine (P < 0.05); multiple Logistic regression analysis showed that older age (OR=1.060, 95%CI, 1.012 to 1.101, P=0.013), low level of eGFR (OR=0.974, 95%CI, 0.953 to 0.996, P=0.019), and high level of SII (OR=1.001, 95%CI, 1.000 to 1.003, P=0.028) were independent risk factors for occurrence of hypoalbuminemia in IgAN patients.

Conclusion High level of SII is an independent risk factor for hypoalbuminemia in patients with IgAN. In clinical practice, the disease progression can be judged by monitoring the SII level, so that measures can be taken in advance to prevent the occurrence of hypoalbuminemia in patients with IgAN.