Zeynep KAYA, Sibel ÖSKEN
Rheumatology Quarterly - 2026;4(3):202-209
Objective: The aggregate index of systemic inflammation (AISI) is a recently introduced composite inflammatory marker derived from neutrophil, monocyte, lymphocyte, and platelet counts. This study aimed to evaluate AISI values in patients with Behçet's disease (BD), compare them with healthy controls, and investigate their association with disease activity assessed by the BD Current Activity Form (BDCAF). Methods: This observational cross-sectional study enrolled 104 patients with BD and 82 age- and sex-matched healthy individuals. Demographic, clinical, and laboratory data were recorded. The AISI was determined according to the following formula: neutrophil x monocyte x platelet / lymphocyte count. Disease activity was assessed using BDCAF. To assess the relationships between variables and determine whether AISI was independently associated with disease activity, correlation analysis, receiver operating characteristic (ROC) analysis, and multivariable linear regression analysis were performed. Results: The AISI was significantly positively correlated with BDCAF scores (rho = 0.630, P < .001). ROC analysis demonstrated that AISI showed discriminative ability between patients with BD and healthy controls within this cohort (area under the curve = 0.871, 95% CI: 0.818-0.918), with a sensitivity of 74.0% and specificity of 86.6%. Moreover, in multivariable linear regression analysis, higher AISI values remained independently associated with higher BDCAF scores after adjustment for age and sex (beta = 0.0044, 95% CI: 0.003-0.006, P < .001). Conclusion: The AISI is significantly associated with inflammatory burden and disease activity in BD. As a readily available hematological index, it may serve as a complementary marker for the assessment of systemic inflammation. Prospective longitudinal studies are needed to determine its clinical applicability.
