Systemic Immune Inflammation Index in IgAN Prognosis

It is widely acknowledged that immune and inflammatory factors are basic underlying mechanisms of IgA nephropathy (IgAN). However, the prognostic value of a new inflammatory biomarker, the systemic immune inflammation index (SII), is unknown. To address this knowledge gap, a group of researchers, including Yaling Zhai conducted a retrospective study of patients with IgAN. Their results were published in Renal Failure.

The study included 374 patients whose IgAN diagnoses were confirmed by biopsy between January 1, 2015, and April 1, 2019. Median patient age was 33 years, and 52.7% were male. Patients were followed for at least 12 months after diagnosis; median follow-up was 32.5 months. The study end point was end-stage renal disease (ESRD).

Based on the optimal cutoff value of the SII determined by receiver operating characteristic curve analysis, patients were divided into a high-risk group (SII ≥456.21) and a low-risk group (SII <456.21). The researchers compared baseline clinicopathological parameters between the two groups and performed Cox proportional hazards analyses and Kaplan-Meier analysis to evaluate renal survival.

A total of 53 patients reached ESRD. Compared with the low-risk group, patients in the high-risk group had a lower hemoglobin level (P=.032) and estimated glomerular filtration rate (P<.001), but higher serum creatinine (P=.023) and 24-hour total protein (P=.004) levels. They also had more severe tubular atrophy and interstitial fibrosis (P=.002) and more crescents (P=.030) versus the low-risk group.

In univariate and multivariate Cox regression analyses, SII ≥456.21 was an independent risk factor for poor renal survival (hazard ratio, 3.028; 95% CI, 1.486-6.170; P=.002). Kaplan-Meier analysis found that high SII had a significant association with poor renal prognosis (P<.001) and consistently showed a strong ability to determine renal survival across different subgroups.

Limitations of the study include its single-center design, small sample size, and short follow-up. The authors also noted that the specificity of the SII for predicting ESRD still needs to be increased.

In sum, the researchers wrote, “A high SII is associated with more severe baseline clinical and pathological manifestations in patients with IgAN, and an SII ≥456.21 is a significant and independent risk factor for renal progression to [ESRD].”

Source: Renal Failure