Hagen 2003.

Methods	Randomised, controlled, concealed allocation, and intention‐to‐treat basis.
Participants	Patients sick‐listed for at least 8 weeks for LBP, mean age 41 years. Total 437 participants were randomised into: Intervention group, N = 237; Control group, N = 220; Inclusion criteria: age 18 to 60 years, a sick leave of 8 to 12 weeks. Exclusion criteria: pregnancy, recent low‐back trauma, and concurrent disorders.
Interventions	Exercise group: Subjects were advised and instructed individually by physiotherapists in how to train and stretch at home, coping with daily activities at home and work, and how to resume normal activities. Control group: Subjects were treated within the primary health care.
Outcomes	Number of subjects with recurrent LBP, and days of sick leaves due to LBP.
Notes	510 people were randomised. The study analysis is based on the following distribution: Intervention, N = 237; Control, N = 220; It appears that 53 participants dropped out after being randomised, which is 10.4% of the population, but before the beginning of the intervention.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk
Allocation concealment?	Low risk	Adequate.
Blinding? All outcomes	High risk	Patients and providers not blinded; unclear if outcome assessors were blinded: 'data from the National Insurance Office'.
Incomplete outcome data addressed? All outcomes ‐ drop‐outs?	Low risk
Incomplete outcome data addressed? All outcomes ‐ ITT analysis?	Low risk
Similarity of baseline characteristics?	Low risk
Co‐interventions avoided or similar?	Low risk	There were no significant differences between the intervention and the control group in the use of analgesics, contacting the physician and relaxation as coping strategies to reduce LBP.
Compliance acceptable?	Low risk
Timing of outcome assessments similar?	Low risk