Psychological predictors of recovery from low back pain: a prospective study

BACKGROUND Recovery from low back pain (LBP) is an important outcome for patients and clinicians. Psychological factors are known to impact the course of LBP but have not been extensively investigated for predicting recovery. The purposes of this study were to: 1) describe LBP recovery rates at 6 months following 4 weeks of physical therapy; 2) identify psychological factors predictive of 6 month recovery status; and 3) identify psychological factors that co-occur with 6 month recovery status. METHODS This study was a secondary analysis of a prospective cohort of patients (n = 111) receiving outpatient physical therapy for LBP. Patients were administered the STarT Back Screening Tool (SBT), individual psychological measures, a numerical pain rating scale (NPRS) and Roland Morris Disability Questionnaire (RMDQ) at intake, 4-week, and 6-month assessments. LBP recovery was operationally defined based on meeting NPRS = 0/10 and RMDQ ≤ 2 criterion at 6-month follow-up assessment. Recovery groups were then compared for differences on all variables at intake and on individual psychological measures at 6-months. Discriminant function analysis (DFA) identified which descriptive variables were predictive of recovery status. RESULTS The 6-month recovery rate was 14/111 (12.6%) for the combined NPRS and RMDQ criterion. Non-recovered patients were associated with SBT risk status (p = 0.004), higher intake pain intensity (p = .008) and higher depressive symptoms (p < .001) scores compared to recovered patients. The overall accuracy for intake classification using DFA was 87.2% with SBT risk status, pain intensity, and depressive symptoms all making unique contributions. At 6-months, non-recovered patients had higher fear-avoidance, kinesiophobia, and depressive symptoms (p's < .001) compared to recovered patients. The overall accuracy for 6-month classification using DFA was 86.4% with fear-avoidance, kinesiophobia, and depressive symptoms all making unique contributions. CONCLUSIONS Our findings indicated that psychological risk status, depressive symptoms, and pain intensity were predictive of 6 month recovery status. Furthermore elevated fear-avoidance, kinesiophobia, and depressive symptoms co-occurred with non-recovery at 6 months. Future studies should investigate whether stratified psychologically informed treatment options have the potential to improve recovery rates for those most at risk for non-recovery.