Racial Disparities in Pain Between Non-Hispanic Whites and Asian Americans with Knee Osteoarthritis: The Role of Pain Catastrophizing

Background: Although a few studies have delineated the disparities in knee osteoarthritis (OA) pain between non-Hispanic Whites (NHWs) and Asian Americans, a significant research gap persists in elucidating the mechanisms underlying these differences. Objective: This pilot study aimed to examine psychological factors, specifically pain catastrophizing and negative affect, as potential explanatory mechanisms for these dissimilarities. Methods: Forty community-dwelling participants aged 50–70 years with self-reported knee OA pain, including 20 NHWs and 20 Asian Americans, were recruited. Clinical knee OA pain intensity was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short -Form-McGill Pain Questionnaire-2 (SF-MPQ-2). Quantitative sensory testing was used to measure experimental sensitivity to heat- and mechanically induced pain. Pain catastrophizing was evaluated using the Coping Strategies Questionnaire-Revised Pain Catastrophizing subscale, while negative affect was assessed using the Positive and Negative Affect Schedule. Bayesian mediation analyses were employed to examine both direct and indirect effects (mediation) between variables. Results: Asian Americans exhibited higher pain catastrophizing scores than NHWs. Pain catastrophizing, at high levels, contributed to WOMAC- and SF-MPQ-2-measured clinical pain, and it fully mediated the relationship between race and these pain measures. However, race had no indirect effects on experimental pain sensitivity through pain catastrophizing. While Asian Americans yielded higher negative affect scores and greater experimental pain sensitivity than NHWs, race exerted no indirect effects on all pain measures via negative affect. Conclusions: Pain catastrophizing appears crucial in addressing racial disparities in clinical knee OA pain between NHWs and Asian Americans. The lack of indirect effects of race on experimental pain sensitivity through pain catastrophizing suggests the need to explore other factors, such as genetic and biological influences. Further research using larger sample sizes is essential to validate our findings and clarify the role of negative affect.