A Mediation Appraisal of Catastrophizing, Pain-Related Outcomes, and Race in Adults With Knee Osteoarthritis

Abstract

The current cross-sectional study investigates whether pain catastrophizing mediates the relationship between ethnicity/race and pain, disability and physical function in individuals with knee osteoarthritis. Furthermore, this study examined mediation at 2-year follow-up. Participants included 187 community-dwelling adults with unilateral or bilateral knee pain who screened positive for knee osteoarthritis. Participants completed several self-reported pain-related measures and pain catastrophizing subscale at baseline and 2-year follow-up. Non-Hispanic Black (NHB) adults reported greater pain, disability, and poorer functional performance compared to their non-Hispanic White (NHW) counterparts (Ps < .05). NHB adults also reported greater catastrophizing compared to NHW adults. Mediation analyses revealed that catastrophizing mediated the relationship between ethnicity/race and pain outcome measures. Specifically, NHB individuals reported significantly greater pain and disability, and exhibited lower levels of physical function, compared to NHW individuals, and these differences were mediated by higher levels of catastrophizing among NHB persons. Catastrophizing was a significant predictor of pain and disability 2-years later in both ethnic/race groups. These results suggest that pain catastrophizing is an important variable to consider in efforts to reduce ethnic/race group disparities in chronic pain. The findings are discussed in light of structural/systemic factors that may contribute to greater self-reports of pain catastrophizing among NHB individuals. PERSPECTIVE: The current study examines whether pain catastrophizing mediates the relationship between ethnicity/race and OA-related pain, disability, and functional impairment at baseline and during a 2-year follow-up period in non-Hispanic Black and non-Hispanic White adults with knee pain. These results point to the need for interventions that target pain catastrophizing.

Keywords: Pain catastrophizing; chronic pain; disability; ethnicity/race; knee osteoarthritis.

Figure 1.

Mediation model show how ethnicity/race group influences SF-MPQ-2 Total, mediated through pain catastrophizing. Note: *P < .05. SF-MPQ-2, Short-form McGill Pain Questionnaire-revised. Covariates include: study site, age, gender, education, body mass index, income, and marital status.

Figure 2.

Mediation model show how ethnicity/race group influences WOMAC Pain, mediated through pain catastrophizing. Note: *P < .05. WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index. Covariates include: study site, age, gender, education, body mass index, income, and marital status.

Figure 3.

Mediation model show how ethnicity/race group influences WOMAC Physical Function, mediated through pain catastrophizing. Note: *P < .05. WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index. Covariates include: study site, age, gender, education, body mass index, income, and marital status.

Figure 4.

Mediation model show how ethnicity/race group influences GCPS Pain, mediated through pain catastrophizing. Note: *P < .05. GCPS, Graded Chronic Pain Scale. Covariates include, study site, age, gender, education, body mass index, income, and marital status.

Figure 5.

Mediation model show how ethnicity/race group influences GCPS Interference, mediated through pain catastrophizing. Note: *P < .05. GCPS, graded chronic pain scale. Covariates include: study site, age, gender, education, body mass index, income, and marital status.

Figure 6.

Mediation model show how ethnicity/race group influences SPPB, mediated through pain catastrophizing. Note: *P < .05. SPPB, short performance physical battery. Covariates include, study site, age, gender, education, body mass index, income, and marital status.

Figure 7.

Mediation model show pain catastrophizing influences AUC knee pain intensity AUC. Note: *P < .05. AUC, area under the curve. Covariates include: study site, age, gender, education, body mass index, income, marital status, and GCPS pain intensity.

Figure 8.

Mediation model show pain catastrophizing influences knee pain interference AUC. Note: *P < .05. AUC, area under the curve. Covariates include: study site, age, gender, education, body mass index, income, marital status, and GCPS pain interference.