A Prospective Cohort Study on Platelet Indices in Children with Sickle Cell Anaemia: Relationship with Disease Severity in a Resource-limited Setting

Background In sickle cell anemia (SCA), activated platelets contribute to vaso-occlusion, the hallmark pathologic process leading to complications that worsen SCA disease severity. Thus, platelet activation markers such as platelet indices (PI) may be related to SCA disease severity (DS). This study aimed to determine the relationship between platelet indices and disease severity in children with SCA. Methods This was a prospective study in which sixty children with SCA aged 6 months to 18 years were consecutively recruited during vaso-occlusive crises (VOC) and followed up to steady state. Their PI were assessed using Mythic 22 auto-analyzer while DS was assessed using an adapted standardized tool, which combined clinical, laboratory and lifetime complications of SCA. Results Platelet count (PC), plateletcrit (PCT), and mean platelet volume (MPV) were higher in VOC than in steady state, with the difference in the PCT being statistically significant (p = 0.01). However, the platelet distribution width (PDW) was lower in VOC compared to the steady state. During VOC, the different PI had weak positive correlation with DS (PC:ρ = 0.04,p = 0.75; MPV: ρ = 0.17,p = 0.19; PDW: ρ = 0.05,p = 0.72; PCT: ρ = 0.08,p = 0.54). In steady state, PC and PCT had weak positive correlation (ρ = 0.10,p = 0.45; ρ = 0.05,p = 0.69 respectively) while MPV and PDW had a weak negative correlation with DS (ρ=-0.17,p = 0.19; ρ=-0.19,p = 0.14 respectively). All the correlation results were not clinically significant. Conclusion and recommendation: Platelet indices are relatively higher during VOC than in steady state. No relationship exists between platelet indices and disease severity in children with SCA. Therefore, platelet-modifying modalities for disease severity may not be required in SCA.