Objective: Acute exacerbations (AECOPD) are primary determinants of clinical instability in chronic obstructive pulmonary disease (COPD), and the “frequent exacerbator” (≥2/year) phenotype markedly increases morbidity and healthcare utilization. In this study, we evaluated the association between the Systemic Immune-Inflammation Index (SII), calculated from routine hemogram parameters during the stable period, and the occurrence of frequent exacerbations within the subsequent 1 year, and aimed to define a clinically applicable SII threshold (cut-off). Materials and Methods: In this retrospective observational cohort study conducted at a tertiary care center, patients who attended the outpatient clinic between January 2020 and February 2025 and had COPD confirmed by post-bronchodilator spirometric criteria (FEV1/FVC 1082.79 (OR = 3.028, 95% CI: 1.522–6.027; p = 0.002) was associated with frequent exacerbations. In a multivariable logistic regression adjusted for cardiovascular disease and overall comorbidity status, SII > 1082.79 remained independently associated (OR = 3.029, 95% CI: 1.485–6.179; p = 0.002). Other hemogram-derived indices did not retain independent prognostic significance in this outpatient cohort. Conclusion: SII measured during stable COPD was independently associated with frequent exacerbations over the subsequent 1 year. The SII > 1082.79 threshold may offer a practical risk stratification approach to flag “high-risk” patients in outpatient care. However, given the modest discriminative performance and the single-cohort derivation, this cut-off should be considered exploratory despite the use of bootstrap internal validation. Because this was a single-center study with a predominantly male cohort, the generalizability—particularly to female patients and other settings—requires prospective external validation.
Dikiş et al. (Tue,) studied this question.