Sickle Cell Disease Demographics and Clinical Epidemiology in Gambian Urban and Rural Cohorts Retrospective Analysis

Globally, approximately 75% of sickle cell disease (SCD) cases occur in sub-Saharan Africa, yet empirical data on its natural history, clinical burden, and modifiers remain scarce in the region. This retrospective study describes the demographic characteristics, complications, and routine care and examines how non-genetic factors and blood markers relate to disease severity. We analysed 8402 medical records from 840 SCD patients with confirmed HbSS genotype registered in MRCG Keneba and Fajara clinics (NKeneba=148; NFajara=692). A generalised linear model was employed to estimate the association of non-genetic correlates, blood biomarkers, and routine care medications with disease severity. Here, we showed 67% of patients in the Keneba cohort and 92% of those in the Fajara cohort had no documented SCD-related chronic complication. Despite no documented evidence of hydroxyurea use, rates of SCD crises (Keneba=0.57, Fajara=0.63) and infections (Keneba=0.53, Fajara=0.35), expressed per patient-year, were low in both cohorts, with 99% of patients experiencing less than or equal to 3 SCD crises per patient-year. Age at diagnosis, gender and seasonality were not significantly associated with SCD crises or other clinical outcomes/events rates. Each additional folic acid prescription was associated with higher haemoglobin(g/dL) (total folic acid prescriptions: Beta-Fajara=1.31, P=0.005; Beta-Keneba=1.20, P<0.001). Penicillin prophylaxis was associated with a reduced rate of infection (total Pen V prescriptions: IRR-Fajara=0.85, P=0.002; IRR-Keneba=0.93, P=0.002) and SCD crises (IRR-Fajara=0.67, P=0.001; IRR-Keneba=0.87, P=0.001). This study found low acute event rates and chronic complications prevalence in the absence of hydroxyurea use. No significant associations were observed between non-genetic correlates and clinical events, but the study highlighted the need for continued folic acid supplementation and penicillin prophylaxis due to their observed beneficial effects.