Severe Persistent Pain and Inflammatory Biomarkers in Sickle Cell Disease: An Exploratory Study

Background: Severe pain is among the most common and deleterious symptoms experienced by individuals with sickle cell disease (SCD), of whom more than 50% report chronic pain. Despite this, the understanding of the biological contributors to persistent severe SCD pain is limited. This exploratory study sought to describe pain phenotypes based on frequency of severe pain experienced over 6 months and identify inflammatory biomarkers associated with pain phenotypes among individuals with SCD. Methods: This study used self-report and electronic health record data collected from 74 individuals enrolled in the Duke Sickle Cell Disease Implementation Consortium Registry. Plasma from previously collected blood specimens was used to generate inflammatory biomarker data using the Inflammation 20-plex ProcartaPlex panel. Descriptive statistics were used to describe the occurrence of severe pain over the past 6 months, and bi-variate analyses were used to evaluate the relationship between inflammatory biomarkers and pain phenotypes. Results: Among the 74 participants included in this study, 33.8% reported severe pain occurring never or rarely, 40.5% reported severe pain occurring sometimes, and 25.7% reported severe pain occurring often or always. Soluble E-selectin (sE-selectin) was the only inflammatory biomarker significantly associated with the pain phenotype groups (p = 0.049). Post hoc comparisons identified that participants in the often/always severe pain group had significantly higher plasma concentrations of sE-selectin compared to those in the sometimes severe pain group (p = 0.040). Conclusions: Our findings provide preliminary evidence of the frequent occurrence of severe pain and that sE-selectin may be an objective biomarker for the frequent occurrence of severe pain in this population.