Red Blood Cell Distribution Width: A Potential Inexpensive Marker for Disease Activity in Patients with Rheumatic Diseases; Scoping Review

Background: Rheumatic diseases encompass a diverse group of autoimmune disorders that affect the joints and connective tissues. The red blood cell distribution width (RDW) has been widely investigated as an inflammatory marker. This scoping review aimed to explore the potential utility of RDW as an inexpensive marker for disease activity in patients with rheumatic diseases. By summarizing the available evidence, we aimed to determine whether RDW can serve as a reliable and accessible indicator of disease activity in these patients. Methods: A comprehensive search was systematically performed across electronic databases, encompassing PubMed, Embase, and Web of Science. Studies have explored the relationship between RDW and disease activity in rheumatic diseases. Data extraction focused on the study characteristics, methodologies, and findings related to RDW as a disease activity marker. Results: After removing duplicates, the initial search yielded 25 relevant studies. These studies encompassed a variety of rheumatic diseases, with rheumatoid arthritis being the most frequently studied condition. The association between RDW and disease activity was assessed by using various disease activity indices and clinical parameters. While some studies have reported a significant correlation between elevated RDW and disease activity, others have yielded inconclusive results. Conclusion: From this review, we concluded that RDW is an inexpensive potential marker for the evaluation of disease activity in rheumatic diseases. RDW is promising as an inexpensive and readily available marker; however, its clinical utility in assessing disease activity in rheumatic conditions warrants more rigorous investigation through well-designed prospective studies.