Clinical utility of red cell distribution width in pulmonary hypertension: A systematic review

Background: Pulmonary hypertension (PH), a disease with a wide range of etiology, refers to the presence of elevated pressure in the pulmonary vasculature. Red cell distribution width (RDW), a measure of anisocytosis of red cells, has gained interest as a biomarker in various disease conditions. This study aimed to review published studies assessing the clinical utility of RDW in PH. Methods: Restricting ourselves to publications between 2000 and 2019, we systematically searched PubMed, Medline, and Embase using pre-defined search criteria. Studies that evaluated the clinical utility of RDW including prognosis, diagnosis, response to treatment, and correlation to disease severity, in the setting of PH were included in the study. Results: A total of 88 abstracts were found, of which 43 were reviewed, 25 full texts retrieved, and 16 studies included in the final analysis after applying exclusion criteria. There was a broad range of study designs, study types, and study populations. There was evidence supporting the use of RDW in diagnosing PH, predicting survival in PH, predicting vasodilator reactivity in PH, and measuring disease severity. Conclusion: RDW appears to correlate with various parameters in PH. Larger studies are needed to elucidate the possible applicability of RDW in the clinical setting.