Lifting capacity is associated with central sensitization and non-organic signs in patients with chronic back pain

Purpose: To analyze the associations between lifting capacity, and central sensitization (CS) and non-organic signs (NOS) in patients with chronic back pain (CBP) attending vocational rehabilitation. Materials and methods: Cross-sectional observational multicenter study among patients with CBP undergoing a return to work assessment within care as usual. Main analyses: step 1: partial correlation between lifting capacity, and CS, NOS, and additional variables; step 2: multiple regression in stepwise forward method for dependent variable lifting capacity, and for independent variables CS and NOS, and additional variables significant (p < 0.05) at step 1. All analyses were controlled for sex. Results: Fifty-six patients of mean age 42.5 years and 59% women participated in the study. Correlations between lifting capacity and CS and NOS were r = –0.53 and r = –0.50, respectively. CS and NOS, as well as age and sex, contributed significantly to the final regression model, which explained 57.6% of variance. Conclusions: After controlling for confounders, CS and NOS were negatively associated with lifting capacity in patients with CBP. Explained variance was substantially higher than previously reported studies.Implications for Rehabilitation The identification of central sensitization and non-organic signs (NOS) in patients with chronic back pain can alert clinicians about central nervous system being in a hypersensitive state and about pain behavior. Central sensitization and NOS are relevant determinants of lifting capacity. Better understanding of the factors affecting lifting capacity lead to better design and tailoring of interventions, resulting in optimized vocational rehabilitation programs and faster return to work.