Increasing days at work using function-centered rehabilitation in nonacute nonspecific low back pain: A randomized controlled trial

Objective: To evaluate the effect of function-centered compared with pain-centered inpatient rehabilitation in patients whose absence from work is due to chronic nonspecific low back pain (LBP). Design: Single-blinded randomized controlled trial with follow-up assessments immediately after treatment and at 3 months. Setting: Center for work rehabilitation in Switzerland. Participants: Patients with more than 6 weeks of work absence due to chronic nonspecific LBP (N = 174; 137 men, 37 women; mean age +/- standard deviation, 42 +/- 8y; mean sick leave before study, 6.5mo). Interventions: Function-centered treatment (FCT) (4h/d, 6d/wk, for 3wk) consisted of work simulation, strength, endurance, and cardiovascular training. Pain-centered treatment (PCT) (2.5h/d, 6d/wk, for 3wk) used a mini back school, individually selected passive and active mobilization, stretching, and low-intensity strength training. Main Outcome Measures: The number of days at work in 3 months after treatment, self-efficacy, lifting capacity, pain, mobility, strength, and global perceived effect. Effect sizes (ESs) (Cohen d) were defined as small (ES range, 0.2-0.5), moderate (ES range, 0.5-0.8), and large (ES, > 0.8). Results: Groups were comparable at baseline. Moderate ESs for the FCT group versus PCT group were found for days at work (25.9d vs 15.8d, ES = .36, P = .029), self-efficacy (5.9 points vs -7.4 points, ES = .55, P = .003), and lifting capacity (2.3kg vs 0.2kg, ES = .54, P = .004). Conclusions: Function-centered rehabilitation increases the number of work days, self-efficacy, and lifting capacity in patients with nonacute nonspecific LBP.