Red cell distribution width and neutrophil-lymphocyte ratio in rheumatoid arthritis

Red cell distribution width (RDW) and neutrophil-lymphocyte ratio (NLR) are potential low-cost markers for detecting rheumatoid arthritis (RA) disease activity, but evidence on their accuracy for this purpose is conflicting. We aimed to determine the relationship between these and the Disease Activity Score of 28 joints (DAS-28) among Filipino RA patients, and to evaluate their ability to discriminate between patients with active RA and those in remission. This was a cross-sectional study done through a 7-year review of medical records of 134 adult patients with RA in a tertiary government hospital. Correlations were analyzed using Spearman analysis, and the receiver operating characteristic (ROC) curve was used to derive the sensitivity, specificity, and optimal cut-off values of RDW and NLR. Most patients were females with a mean disease duration of 7 years. Eighty-one percent (81%) had active disease using DAS-28 ESR. A weak positive correlation was found between NLR and DAS-28 and between NLR and ESR, but RDW did not correlate with either DAS-28 or ESR. The ROC analysis showed that in the differentiation of active RA and inactive RA, both RDW (area under the curve [AUC] 0.516, cut-off of ≥ 14.2% with 55.6% sensitivity and 42.3% specificity) and NLR (AUC 0.629, cut-off of ≥ 2.32 with 54.6% sensitivity and 76.9% specificity) had poor performance. NLR, but not RDW, was positively but weakly correlated with DAS-28 and ESR, making it a helpful marker of disease activity and inflammation in RA. Both NLR and RDW had low sensitivity and specificity for active RA and may not be useful in detecting disease activity.