The significance of inflammatory markers derived from blood cell counts in predicting rheumatoid arthritis among the elderly

Abstract

Introduction

The systemic immune inflammation index and neutrophil-platelet-to-lymphocyte–hemoglobin ratio are blood-cell-based markers that have recently been described as significant predictors of systemic inflammation in related diseases. However, these markers have not been studied in rheumatoid arthritis and their relationship to aging has not been explored.

Materials and methods

In this case–control study, systemic immune inflammation index and neutrophil-platelet-to-lymphocyte–hemoglobin ratio were analyzed in two age groups of rheumatoid arthritis patients: <40 years (young adults; RA_Y) and >60 years (elderly; RA_E). Similar control groups were included (HC_Y and HC_E, respectively). Each group consisted of 50 individuals (total number = 200) with a 1:1 male-to-female ratio.

Results

Systemic immune inflammation index and neutrophil-platelet-to-lymphocyte–hemoglobin ratio were significantly elevated in RA_Y and RA_E compared to HC_Y and HC_E, respectively. Neutrophil-platelet-to-lymphocyte–hemoglobin ratio was also significantly elevated in RA_E compared to RA_Y. When systemic immune inflammation index and neutrophil-platelet-to-lymphocyte–hemoglobin ratio were stratified by gender, disease duration, disease activity, or therapy type, no significant differences were found. Disease duration in RA_Y was an exception, and systemic immune inflammation index and neutrophil-platelet-to-lymphocyte–hemoglobin ratio gradually decreased with increasing disease duration. Neutrophil-platelet-to-lymphocyte–hemoglobin ratio showed a very good performance in distinguishing between RA_E and HC_E (area under the curve = .831). Neutrophil-platelet-to-lymphocyte–hemoglobin ratio was also a significant marker in increasing the risk of rheumatoid arthritis (1.20-fold), particularly in the elderly (1.33-fold). The two blood-cell-based markers showed strong positive pairwise correlations in RA_Y and RA_E.

Conclusion

The study indicates for the first time that the blood-cell-based inflammatory markers, systemic immune inflammation and neutrophil-platelet-to-lymphocyte–hemoglobin ratio, are cost-effective predictors of rheumatoid arthritis and are associated with the risk of developing the disease, especially in the elderly.