Return to work
During 12 months of follow up 89%, 88% and 86% of the participants achieved sustainable RTW in the MI, usual case management, and active control group, respectively. One participant died during follow- up and was censored. Two participants emigrated, but this was close to the end of follow-up, and they did not receive medical benefits at the time they emigrated. The Kaplan-Meier plot is shown in figure 3. The difference between the groups was not statistically significant (log rank test P=0.689). Median time to sustainable RTW was 159 days for the MI group, 161 days for the usual case management, and 168 days for the active control group. The unadjusted HR for sustainable RTW was 1.01 (95% CI 0.92–1.11) for the MI group compared to the usual case management and 1.08 (95% 0.90–1.31) compared to the active control group. The adjusted HR were 1.12 (95% CI 0.90–1.40) and 1.16 (95% CI 0.93–1.44), respectively. The estimated per-protocol effect for MI compared to usual case management gave a HR for sustainable RTW of 1.00 (95% CI 0.78–1.29).Several participants experienced new sick leave episodes during follow-up, and at 12 months the number of participants at work was 65%, 69% and 64% for the MI, usual case management, and active control groups, respectively. When evaluating sustainable RTW during the follow-up period, the group that received MI had a slightly larger probability of RTW for certain months, but the groups were closely matched during the first few months of follow-up (as shown in the supplementary figures S1 and S2). Number of participants transitioning to the more long-term benefit work assessment allowance was lower in the usual case management group (14%) than in the MI (19%) and active control group (21%).Survival curves from the Kaplan Meier intention to treat analysis showing time to sustainable return to work (ie, 1 month not receiving medical benefits) for the motivational interviewing, usual case management and active control group during 12 months of follow-up.