The STarT Back trial demonstrated that targeting back pain treatment according to patient prognosis (low, medium or high-risk subgroups) is effective. However, the mechanisms leading to these improved treatment outcomes remain unknown. This study aimed to identify which psychological variables included in the study were mediating treatment outcome for all patients and within the low, medium and high-risk subgroups. Secondary analysis was conducted on 466 patients randomised to the active treatment arm with 4-month follow-up available. Psychological variables included depression (HADs), fear (TSK), catastrophising (PCS), bothersomeness and illness perception constructs (IPQ brief) e.g. personal control. Treatment outcome was characterised using change in disability score (RMDQ) at 4-months. Residualised change scores were calculated for each variable and Pearson's correlations were calculated overall and at the subgroup level to determine potential mediating variables for disability improvement.Introduction
Methods
