Could hematological indices predict the response of rheumatoid arthritis patients to biological drugs?

Abstract
Background
The present cohort study with a control group aimed to evaluate the predictive value of hematological indices in assessing treatment response to biological drugs, including Janus Kinase (JAK) inhibitors, and their impact on these indices.

Methods
The study included 115 RA patients with active disease and 67 age- and sex-matched healthy volunteers. All patients were assessed at baseline and after 6 months of biological treatment. The disease Activity Score of 28 joints using the erythrocyte sedimentation rate (DAS28-ESR) and Clinical Disease Activity Index (CDAI) were evaluated. The hematological indices used were the neutrophil-to-lymphocyte ratio (NLR), neutrophil-to-hemoglobin and lymphocyte (NHL) score, platelet-to-lymphocyte ratio (PLR), platelet-to-hemoglobin ratio (PHR), monocyte-to-lymphocyte ratio (MLR), and Systemic Immune-Inflammation Index (SII).

Results
At baseline, The RA patients had significantly lower hemoglobin levels, a greater monocyte count, a greater platelet count, a significantly greater MLR, PLR PHR, NHL score, and SII than the control group (p ≤ 0.05). Neutrophil and lymphocyte percentages were positively correlated with the DAS28-ESR and CDAI. The PHR and NHL ratios were correlated with the ESR and CDAI. Biological treatment significantly decreased neutrophil, monocyte, and platelet counts, the MLR, the PHR, the NHL score, and the SII (p ≤ 0.05). Changes in the SII and NHL scores were associated with changes in the DAS28-ESR during treatment. No hematological indices showed predictive potential for nonresponse to biological treatment.

Conclusion
Hematological indices, such as MLR, PHR, NHL score, and SII, remain valuable despite not predicting non-response to treatment. These indices are cost-effective and widely available tools that correlate with RA disease activity, offering clinicians actionable insights into the inflammatory status of patients. Their utility lies in tracking treatment efficacy and guiding adjustments in therapeutic strategies, ensuring better disease management and improving patient outcomes.