Discussion
CMDs
This study showed that 80.9% of the participants achieved a first full RTW during the 12-month follow-up, with the majority (59.3%) within the first six months. High psychological and emotional job demands, high WHI, and low social job support at baseline were independently associated with a longer time to first full RTW. Significant differences between time intervals (0– ≤ 6- and > 6–12 months) were found in a post hoc analysis of the associations between low job control and high emotional job demands, and time to first full RTW. Low job control was associated with a shorter time to first full RTW between 0 and ≤ 6 months and with a longer time to first full RTW between > 6 and 12 months.A direct comparison across studies of time to RTW after CMDs is difficult due to differences in administrative settings and design. Our results are in line with a recent Swedish RCT conducted in occupational health services among employees absent from work due to CMDs. Here, 82% had returned to their ordinary working hours during a 12-month follow-up (Keus van de Poll et al. The association between high psychological job demands and a longer time to first full RTW in our study has been demonstrated in previous studies (Flach et al. The post hoc analysis showed differences between time intervals for the associations between low job control and high emotional job demands and time to first full RTW. Investigating phase-specific factors is relevant because of the developmental nature of the RTW process (Krause et al. A strength of the study was the longitudinal design and the follow-up by repeated text messages. Although self-reported sick leave outcomes entail a risk of bias, text messaging has demonstrated high compliance (Axén et al. One of the study’s limitations is the possibility of response and recall bias because of the self-reported data collected retrospectively. Baseline data were collected when the employee was on sick leave. Moreover, the eligibility criteria ‘having to accept employer involvement’, might imply that included participants had a positive perception of their employer and decreased the variance in, and affected the outcome of, fair leadership. Moreover, we do not know exactly when the first full RTW occurred. Because text messages were sent every fourth week, precision was limited. This uncertainty was incorporated into the estimation to reduce the risk of bias. Additionally, missing values preceding the first positive answer were accounted for by widening the censoring interval. Missing values followed by a negative answer were interpreted as a negative answer, ensuring that we did not underestimate the time to the first full RTW. Given the sample size, only the main factors associated with RTW after sick leave due to CMDs were introduced in the adjusted model, the possibility of other confounders needs to be considered in the interpretation of the results. Moreover, because a large majority of the sample were female employees born in Sweden, sub-group analyses based on gender or ethnicity were not possible.The importance of organisational measures to improve RTW is previously highlighted (cf. Gensby et al. 