Background:

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease involving multiple organ systems, characterized by heterogeneous pathogenesis, diverse clinical manifestations, prolonged disease course, and substantial morbidity and mortality.

Objectives:

This study aimed to systematically evaluate the clinical value of 11 hematological indices derived from routine blood tests in assessing disease activity in patients with SLE.

Design:

This retrospective observational study analyzed the correlation between hematological biomarkers and clinical disease activity indicators in enrolled patients. Receiver-operating characteristic (ROC) curves were employed to evaluate the predictive efficacy of each indicator for disease activity, while binary logistic regression analysis was used to identify independent risk factors influencing disease activity.

Methods:

Clinical and laboratory data from 100 patients with SLE were retrospectively analyzed. Associations between blood routine–derived indices and disease activity were assessed. Receiver-operating characteristic curves were used to evaluate the predictive performance of these indices for SLE activity, and binary logistic regression analysis was conducted to identify independent risk factors.

Results:

Compared with healthy controls, patients with SLE exhibited significantly higher levels of platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), systemic inflammatory response index (SIRI), aggregated inflammatory systemic index (AISI), derived neutrophil-to-lymphocyte ratio (dNLR), neutrophil-to-lymphocyte-platelet ratio (NLPR), monocyte-to-lymphocyte ratio (MLR), and RDW/PLT ratio (RPR) (all P < .05), whereas HGB/RDW ratio (HBR) was significantly lower. Disease activity was positively correlated with SIRI, SII, AISI, PLR, NLR, dNLR, NLPR, and MLR (P < .05 or P < .01), while mean platelet volume-to-platelet ratio (MPR) and RPR showed significant negative correlations with disease severity. The ROC analysis demonstrated that SIRI, SII, AISI, PLR, NLR, dNLR, NLPR, MLR, RPR, and a combined predictive model effectively discriminated active disease, with the combined model yielding the highest area under the curve (AUC). Among individual indices, SII and NLR showed the strongest predictive performance.

Conclusion:

Blood routine–derived inflammatory indices, particularly SII and NLR, are effective tools for evaluating disease activity in SLE. After adjustment for potential confounders, elevated SII was identified as an independent risk factor for increased disease activity, highlighting its potential clinical utility in routine assessment of patients with SLE.