Racial Discrimination and Pain in Adults with Sickle Cell Disease: Depression As a Mediator

Introduction: Patients with sickle cell disease (SCD) are highly vulnerable to pain and depression compared to their healthy peers. They also are at high risk of experiencing discrimination due to a combination of racial biases and stigma associated with SCD. Discrimination can have negative psychological effects and lead to poor health outcomes including increased pain. However, there is limited research in SCD examining the link between racial discrimination and pain, and how depression may mediate this association. A recent study found that depression significantly mediated the association between racial discrimination in the healthcare setting and pain severity and interference in adults with SCD. This study lacked a comparison group of non-SCD racial minorities to determine to what extent the link between discrimination and pain was specific to SCD. Thus, in the current study we sought to extend prior findings by comparing depression, pain, and racial discrimination between a group of adults with SCD and a demographically matched control group. We then examined whether depression in adults with SCD mediated the racial discrimination - pain association.

Methods: Our study included 96 adults ( M _age = 35.22 years, SD = 11.24; 55 females) with SCD receiving hematological care at a large medical center in the northeastern United States, and 84 demographically matched non-SCD controls ( M _age = 36.66, SD = 11.49; 50 females). The institution's IRB approved the study, which involved collection of biopsychosocial data from participants. Rating scales used in the current study included the Experiences of Discrimination Scale (EOD), Beck Depression Inventory-2 (BDI-2), and Brief Pain Inventory (BPI).

Results: After adjusting for covariates, the SCD group rated themselves as experiencing significantly more depression (BDI-2) ( t(95) = -1.997, p = 0.024) in daily life than the control group. Discrimination (EOD) was not significantly different between groups ( t(138) = -1.029, p = 0.305). The SCD group endorsed marginally greater 0-10 pain severity on the BPI than the control group, which approached significance ( p = .053) with a medium effect size ( adjusted R ² = .193). Lack of significance was likely influenced by the small number of non-SCD controls who completed the BPI ( n = 12). In the SCD group, depression was significantly associated with both pain ( r = .509, p = .004) and discrimination ( r = .497, p = .005). Discrimination was not significantly associated with pain ( r = .219, p = .245). Using Andrew Hayes's PROCESS mediation macro, results showed a significant indirect effect in that depression (BDI-2) fully mediated the association between racial discrimination (EOD) and pain ratings (BPI) (Table 1, Figure 1). No mediation was found using the same analyses in the control group.

Conclusion: The SCD and non-SCD groups reported experiencing similar levels of racial discrimination but the SCD group reported higher levels of depression and pain. In the SCD group, we replicated prior findings showing that depression mediated the associated between discrimination and pain. This suggests that it is an individual's response to an external stressor, and not the stressor itself, that contributes to poor disease outcomes. SCD primarily impacts Βlacks/African Americans in the United States, and these patients may experience unique interactions between experiences of discrimination and mental health that lead to increased pain. Depression may be a focus for treatment to improve pain, but more research is needed to substantiate these findings and understand what physiological factors explain how depression can influence pain in SCD.