Hydroxyurea in Sickle Cell Disease: Coagulation and Activation in an Observational Study

Sickle cell disease (SCD) is characterized by a chronic hypercoagulable state. Hydroxyurea (HU) is known to reduce the frequency of vaso-occlusive events and transfusion requirements in affected individuals.

To assess the impact of hydroxyurea on biomarkers of coagulation (D-dimer) and endothelial activation (soluble VCAM-1) in SCD patients in Pakistan in their steady state.

A prospective observational study was conducted in patients aged ⩾ 10 years with confirmed HbSS or HbSβ-thalassemia genotypes. Biomarkers were measured at baseline and after 6 months of HU therapy.

Twenty-five patients (HbSS = 15 [60%], HbSβ-thalassemia = 10 [40%]) with a median (IQR) age of 23 (16.5-27) years were enrolled. A significant decrease in D-dimer levels was observed after HU treatment: from a median of 1243 to 830 ng/mL (P = .028), reflecting a 33% reduction. Soluble VCAM-1 levels showed no statistically significant change (532.6 vs 492.9 ng/mL, P = .381). HbF increased from 20.1% (12.6-27.5) to 28% (20-39) (P < .001), with a strong positive correlation with HU treatment (r = .845).

This study demonstrates that HU therapy in Pakistani SCD patients significantly reduces D-dimer levels, suggesting reduced thrombotic activity. While the endothelial marker VCAM-1 showed no significant change, the rise in HbF is consistent with known HU effects.