Elevated body mass index and obesity are associated with pain-associated psychological distress in patients with hip pain

Introduction: Little research has investigated the relationship between musculoskeletal pain and body mass index (BMI) in the context of pain-associated psychological distress. This study aims to determine if independent associations exist between BMI, obesity, demographic variables, and psychological distress in patients presenting with hip pain.

Materials and methods: Using a retrospective cross-sectional study design, 428 patients completed the Optimal Screening for Prediction of Referral and Outcome Yellow Flag (OSPRO-YF) and were categorized into pain-associated psychological distress phenotypes using latent class analysis. Participants were stratified into five BMI categories outlined by the Centers for Disease Control and Prevention (CDC) using descriptive statistics. Multinomial logistic regression was employed to determine a relationship between psychological distress phenotype and BMI (first as a continuous variable, then as a categorical variable), age, gender, race, and veteran status as candidate variables.

Results: Four psychological distress phenotypes were generated: high distress (n = 172, 40.2%), low distress (n = 114, 26.6%), negative pain coping (n = 98, 22.9%), and low self-efficacy and acceptance (n = 44, 10.3%). BMI analyses identified 4 participants (0.9%) as being underweight (BMI < 18.5), 146 participants (34.1%) with recommended weights (18.5 < BMI < 24.9), 133 (31.1%) as overweight (25 < BMI < 29.9), 113 (26.4%) with obesity (30 < BMI < 39.9), and 32 (7.5%) with severe obesity (BMI > 40). Additionally, 54.0% of participants with obesity and 59.4% of participants with severe obesity had high psychological distress. As a continuous and categorical variable, elevated BMI was independently associated with membership in the high distress phenotype (p < 0.001). The overweight (p = 0.043), obesity (p < 0.001), and severe obesity (p = 0.034) subgroups and Black/African American participants (p = 0.020) were also all significantly associated with high distress.

Conclusions: Elevated BMI and obesity are associated with high psychological distress in patients with hip pain. These results may inform operative, nonoperative, and behavioral health treatment pathways for patients with comorbid obesity and hip pain, as well as provide direction for prospective studies to address obesity and psychological distress among patients with musculoskeletal pain.