High baseline neutrophil-to-lymphocyte ratio predicts better adalimumab response in rheumatoid arthritis

Despite significant advancements in managing rheumatoid arthritis (RA) with tumor necrosis factor (TNF) inhibitors like adalimumab, a substantial proportion of patients (20-40%) do not achieve clinical remission. This variability in response highlights a critical unmet clinical need for reliable biomarkers that can predict therapeutic outcomes, allowing for more personalized treatment strategies and avoiding ineffective therapies. Understanding factors that influence adalimumab efficacy, particularly easily accessible and cost-effective markers such as the neutrophil-to-lymphocyte ratio (NLR), could significantly improve patient selection and optimize treatment pathways for this chronic inflammatory autoimmune disease.

This prospective observational study enrolled 189 patients diagnosed with rheumatoid arthritis to identify predictors of adalimumab response. Researchers analyzed a comprehensive set of baseline demographic, clinical, therapeutic, disease activity, and serological parameters, including serum concentrations of proinflammatory cytokines. The primary endpoint was treatment response, assessed using the Disease Activity Score in 28 joints (DAS28) at week 24. Patients were treated with adalimumab according to standard clinical practice, and their NLR was calculated from routine complete blood counts prior to initiating therapy.

A higher baseline neutrophil-to-lymphocyte ratio (NLR) was identified as a significant independent predictor of a favorable response to adalimumab therapy. The odds ratio for a good response with a high baseline NLR was 3.1 (95% confidence interval: 1.04-7.50, p = 0.019). This suggests that patients starting with an elevated NLR are more than three times as likely to respond positively. Among those who achieved a good response, NLR levels significantly decreased following the initiation of TNF inhibitor treatment (p < 0.001), indicating a reduction in systemic inflammation. Patients who achieved DAS28-defined remission at week 24 had significantly higher baseline NLR values compared to non-remitters (p < 0.001).