Psychological mediators in chronic spinal pain after fully remote digital rehabilitation: a real-world, large-sample study

IMPORTANCE: Psychological factors are associated with chronic spinal pain, yet their mediating role in postrehabilitation recovery remains poorly understood, particularly in fully remote digital care. Most research has focused on baseline predictors, with few studies evaluating psychological mediators and moderators. OBJECTIVE: The objective of this study was to investigate whether changes in fear avoidance beliefs, depression, and anxiety mediate pain outcome following a digital care program (DCP) for chronic spinal conditions and whether these effects vary by Body Mass Index (BMI), self-reported gender, and socioeconomic status. DESIGN: This was an ad hoc analysis of a real-world registry of patients undergoing a DCP. SETTING: The setting was a fully remote DCP delivered across the United States. PARTICIPANTS: The participants were adults who had chronic spinal musculoskeletal pain (N = 14,818) and who accessed the DCP via employer-sponsored health plans. INTERVENTION: The DCP consisted of exercise, education, and behavior change, managed asynchronously by physical therapists. MAIN OUTCOMES AND MEASURES: The final pain score (11-point numeric pain rating scale) was the primary outcome. Candidate mediators were changes in fear avoidance beliefs, depression, and anxiety. Confounding was mitigated through demographic and clinical covariates. Moderation was tested for BMI, self-reported gender, and socioeconomic deprivation. Structural equation modeling was used. RESULTS: Improvements in fear avoidance beliefs (β = -0.10, SE = 0.00), depression (β = -0.05, SE = 0.01), and anxiety (β = -0.04, SE = 0.01) significantly mediated lower final pain scores after adjustment for confounding. The mediating effect of fear avoidance was especially pronounced among patients with severe obesity. Self-reported gender and socioeconomic status did not show moderating effects. The model's explained variance was 30%. CONCLUSIONS AND RELEVANCE: Changes in fear avoidance beliefs, depression, and anxiety play a central role in pain recovery following digital rehabilitation. Fear avoidance mediation was particularly strong in individuals with severe obesity, highlighting the need for targeted psychological support in this subgroup. The findings emphasize the pertinence of systematically screening, monitoring, and addressing psychological factors in remote care, contributing to understanding how digital rehabilitation promotes recovery.