Integrated haematological, inflammatory and endothelial biomarkers in steady-state and vaso-occlusive crisis of sickle cell disease: a case-control study in Benin City

Integrated evidence on haematological, inflammatory, and endothelial biomarker profiles across clinically distinct sickle cell disease (SCD) states remains limited in African populations. This study evaluated these biomarkers among individuals with steady-state SCD, vaso-occlusive crisis (VOC), and healthy controls in Benin City, Nigeria. This case-control study included 89 participants: 20 with steady-state SCD, 32 presenting with VOC, and 37 healthy controls. Haematological parameters, complete blood count-derived inflammatory indices, C-reactive protein (CRP), interleukin-6 (IL-6), and soluble vascular cell adhesion molecule-1 (sVCAM-1) were assessed. Between-group differences and the within-cohort discrimination of VOC from steady-state SCD were evaluated using conventional and exploratory multivariable approaches. Participants with VOC showed greater haematological abnormalities and inflammatory and endothelial activation than those in steady state. Among individual markers, NLR, CRP, IL-6, and sVCAM-1 showed comparatively strong within-cohort discrimination of VOC status, with AUCs of 0.816, 0.857, 0.882, and 0.901, respectively. An integrated biomarker model yielded an AUC of 0.938, although performance was estimated within the same modest SCD cohort. Inflammatory and endothelial biomarkers differed across SCD clinical states and showed potential as adjunctive markers of disease activity. Larger prospective studies accounting for treatment exposure and providing independent validation are required before clinical application.