ORIGINAL ARTICLE Characterization of neutrophil-to-lymphocyte ratio as a measure of inflammation in rheumatoid arthritis S. CHANDRASHEKARA, 1 Masoodi MUKHTAR AHMAD, 1 Panchagnula RENUKA, 2 K. R. ANUPAMA 1 and K. RENUKA 1 1 ChanRe Rheumatology and Immunology Centre, and 2 ChanRe Diagnostic Laboratory, Bangalore, India Abstract Objectives: The neutrophil to lymphocyte ratio (NLR) is one of the well-recognized sensitive measures of inflammation. This cross-sectional observational study was aimed at characterizing the relationship of NLR with the inflammatory markers erythrocyte sedimentation rate (ESR), C-reative protein (CRP), Disease Activity Score of 28 joints (DAS28)-CRP(3), joint counts and quality measures of rheumatoid arthritis (RA). Materials and Methods: Patients with RA were recruited in two phases. The following were assessed for all patients: joint count, pain by visual analogue scale (VAS), complete blood count, ESR, CRP and quality index assessment using the Short Form health survey (SF-36) questionnaire. A subgroup analysis was also performed to evaluate the association between NLR and cytokines. Results: Four hundred and eighty-nine subjects were recruited. Distribution of NLR values corresponded with DAS28-CRP(3) rather than CRP and ESR. A significant difference in VAS, swollen joint counts (SJC-28), inflam- matory parameters and general health outcome measures was observed among the NLR groups. A weak correla- tion was observed between NLR and RA disease measures. It had least bias at lower ranges with DAS28-CRP(3) than CRP and ESR. The NLR cut-off value of 1.4 classified the patients in deep remission with 90% specificity, 24% sensitivity, likelihood ratio positive (LR+) 2.46 and likelihood ratio negative (LRÀ) 0.84. CRP was a signifi- cant baseline predictor of NLR. A significant influence of interleukin-6 on CRP was noted. Conclusion: In contrast to the traditional markers, NLR may serve as a less expensive and effective measure of inflammation in RA. Its efficacy is comparable to that of CRP and it is not impacted by the cytokines influencing CRP and ESR. Key words: cytokines, DAS28-CRP(3), ELISA, mountain plot, neutrophil-lymphocyte ratio, rheumatoid arthritis. INTRODUCTION Inflammation is the key component of rheumatoid arthritis (RA) pathology. The current treatment strategy for RA is focused on reducing the disease activity to the lowest possible level. Accurate measurement of disease activity (inflammation) is essential for customizing the treatment strategy and several studies have underscored the limitations of currently used measures of RA like erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), disease activity score (DAS), and clinical disease activity index (CDAI). The major disadvantage of these measures is that they attain a flooring effect at lower dis- ease activity. 1 Ultrasound and magnetic resonance imaging have been reported to show synovial inflam- mation, even when ESR, CRP and DAS have reached the lowest or near normal levels. However, these techniques are expensive and time consuming. The inflammation Correspondence: Professor S. Chandrashekara, ChanRe Rheumatology and Immunology Centre, 149, 15th main, NHCL water tank Road, 4th Block, 3rd stage, Basaweswarana- gar, Bangalore 560079, India. Email: chandrashekara_s@yahoo.com © 2017 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd International Journal of Rheumatic Diseases 2017; 20: 1457–1467