Hemoglobin-to-Red Cell Distribution Width Ratio and Vitamin D Status as Early Predictors of Cardiovascular Risk in Primary Sjögren’s Syndrome

Introduction: Primary Sjögren’s (pSS) is an autoimmune disease that affects several organs, especially the heart, and raises cardiovascular risk. Investigating the associations of hemoglobin-to-red cell distribution width (RDW) ratio (HRR), vitamin D status, and cardiac function could provide valuable insights and biomarkers regarding early cardiovascular risk in patients with pSS. Method: This cross-sectional study involved 61 patients diagnosed with pSS based on ACR/EULAR criteria. Data on demographics, hematological (Hb, RDW), echocardiography, and serum vitamin D levels were collected. Echocardiograms were conducted by trained cardiologists following established guidelines, while vitamin D levels were measured using ELISA. Statistical analyses, including univariate linear regression, were performed with SPSS in order to identify whether HRR tertiles were related to cardiac function and vitamin D status. Results: A study of 61 pSS patients (mean age 59.8 years, 89% female) revealed that patients with a lower hemoglobin-to-RDW ratio (HRR ≤ 0.98) had significantly higher pulmonary artery pressures (PAPs) and lower values for the tricuspid annular plane systolic excursion (TAPSE)/PAPs ratio, contributing to poor right heart function. These associations were particularly strong in patients with insufficient levels of vitamin D (<30 ng/mL), while differences in other echocardiographic parameters remained nonsignificant between HRR groups. Conclusions: These findings underscore the clinical value of HRR as a composite biomarker that reflects the interplay between anemia, inflammation, and cardiovascular health in primary Sjögren’s disease. They also suggest that vitamin D status may be an important therapeutic consideration to mitigate cardiopulmonary risks in this population.