Characteristics and findings of the included studies
| Author (year) | Place of study | Study design | Length of follow-up | Study population | Sample size and dropout | Significant main factors* | Non-significant main factors | Measurements of RTW |
| Berglind and Gerner (2002)46 | Sweden | Prospective cohort | 24 months | Age: 18–55 years Gender: NA Pain: low back and neck Work absence: ≥8 weeks Pain duration: ≥8 weeks | n=289 Response rate: NA Dropout: NA | Work motivation | Work status (Yes/No) | |
| Du Bois et al (2009)49 | Belgium | Prospective cohort | 6 months | Age: 18–64 years Gender: male and female Pain: low back Work absence: ≥4 weeks Pain duration: ≥4 weeks | n=390 Response rate: 89% Dropout: 0% | Disability Pain behaviour Fear avoidance beliefs Type of work Prior pain duration | Work status (Yes/No) | |
| Gallagher et al (1995)47 | USA | Prospective cohort | 6 months | Age: ≥18 years Gender: male and female Pain: low back Work absence: ≥24 weeks Pain duration: ≥24 weeks | n=169 Response rate: NA Dropout: 6% | Compensation status Use of lawyer | Work status (Yes/No) | |
| Gross et al (2004) part I50 | Canada | Retrospective cohort (two cohorts) | 12 months | Age: x̅=41 (c1), 40 (c2), SD=10 (c1), 9 (c2) years Gender: male and female Pain: low back Work absence :≥6 weeks Pain duration: ≥6 weeks | n=150 (c1), NA (c2) Response rate: 76% (c1), NA (c2) Dropout: 32% (c1), 34% (c2) | Functional capacity | Time until suspension of time-loss benefits, time until claim closure | |
| Gross and Battié (2005)51 | Canada | Prospective cohort | 12 months | Age: x̅=42, SD=11 years Gender: male and female Pain: low back Work absence: ≥6 weeks Pain duration: ≥6 weeks | n=138 Response rate: 70% Dropout: 54% | Recovery beliefs | Time until suspension of time-loss benefits, time until claim closure | |
| Hansson et al (2006)52 | Sweden | Prospective cohort | 24 months | Age: 18–59 years Gender: male and female Pain: low back or neck Work absence: ≥4 weeks Pain duration: ≥4 weeks | n=1575 Response rate: 64%–79% Dropout: 28%–55% | Quality of life Disability | Prevalence of work resumption | |
| Kuijer et al (2012)53 | Netherlands | Prospective cohort | 12 months | Age: 18–55 years Gender: male Pain: low back Work absence: ≥6 weeks Pain duration: ≥6 weeks | n=72 Response rate: NA Dropout: 4% | Work ability | Age Functional capacity | Time until working ≥4 weeks |
| Schultz et al (2004)54 | Canada | Prospective cohort | 3 months | Age: 18–60 years Gender: male and female Pain: low back Work absence: ≥4 weeks Pain duration: ≥4 weeks | n=781 Response rate: 32% Dropout: 15% | Health transition Recovery expectations | Coworker support | Work status (Yes/No) |
| Schultz et al (2005)48 | Canada | Prospective cohort | 3 months | Age: 18–60 years Gender: male and female Pain: low back Work absence: 4–6 weeks Pain duration: ≥4 weeks | n=111 Response rate: NA Dropout: 9% | Recovery expectations Symptoms/complaints | Vitality Mental health | Work status (Yes/No) |
| van der Giezen et al (2000)55 | Netherlands | Prospective cohort | 12 months | Age:18–60 years Gender: male and female Pain: low back Work absence: ≥12 weeks Pain duration: ≥12 weeks | n=328 Response rate: 91% Dropout=9% | Age General health Job satisfaction Breadwinner Pain intensity | Work status (Yes/No) |
*In all articles, except Berglind and Gerner46 and Hansson et al 52 p<0.05 has been used as level of significance.
c1, cohort 1; c2, cohort 2; NA, not applicable; RTW, return to work.