Red Blood Cell Distribution Width as a Surrogate Marker of Disease Activity in Patients with Rheumatoid Arthritis

Objective: To determine the association between red blood distribution width and disease activity in patients with rheumatoid arthritis and to compare the red blood distribution width in patients of rheumatoid arthritis with that in healthy subjects. Methodology: This comparative case-control observational study was conducted at Pakistan Institute of Medical Sciences, on rheumatoid arthritis patients visiting the (Out Patient Departments) OPDs between September, 2020 and March, 2021. Study subjects were selected by non-probability convenient sampling and a control group comprising of healthy subjects was similarly selected from general medical OPDs. Complete blood picture and erythrocyte sedimentation rate were obtained for each patient and disease activity score was calculated for rheumatoid arthritis patients. Statistical Package for Social Sciences (SPSS) version 26 was used for data analysis. Data was checked for normality by using the Kolmogorov Smirnov test. An independent samples t-test was used for comparing means and Pearson’s correlation coefficient for establishing an association between variables. P value less than 0.05 was considered significant. Results: Of the total 140 patients, 60 (85.7%) in each group were female and 10 (14.3%) were male. The mean age was 39.23 years and 36.87 years in the case and control groups respectively. The mean disease duration of rheumatoid arthritis was 6.63 years. RDW was significantly elevated in patients with rheumatoid arthritis (16.82%) as compared to the control group (14.47%) and strong positively correlated with disease activity score (p 0.00038). Conclusion: Red blood cell distribution width is strongly related to disease activity in patients of rheumatoid arthritis and may help in monitoring disease activity in rheumatoid arthritis patients