Correlation analysis of systemic immune-inflammation index values and arthritis risk in adults

Objective To investigate the correlation between systemic immune-inflammation index (SII) values and the risk of arthritis among adult participants. Methods Cross-sectional data from adult participants (aged ≥18 years) in the National Health and Nutrition Examination Survey 2011–2018 dataset were utilized. The association between systemic immune-inflammation index values and arthritis risk was explored through multivariate regression and restricted cubic spline model-based analyses. Results An analysis of categorical variables indicated that the risk of arthritis was significantly higher in the highest systemic immune-inflammation index quartile (Q4) compared with the lowest quartile (Q1; odds ratio = 1.36, 95% confidence interval = 1.23–1.51). Continuous variable and spline model analyses suggested that there was a significant and positive correlation between high systemic immune-inflammation index values and an increased risk of arthritis (odds ratio = 1.12, 95% confidence interval = 1.08–1.16, p < 0.001). A subgroup analysis revealed that this correlation was stronger in the older population than in the younger population (p interaction = 0.041). A sensitivity analysis suggested that the association between systemic immune-inflammation index values and arthritis risk was stable. Conclusions Our research suggests a correlation between high systemic immune-inflammation index values and an increased risk of arthritis within the examined sample. Consequently, tracking systemic immune-inflammation index values could potentially facilitate the early detection of arthritis.