Return to work : methods for promoting health and productivity in employees on sickness absence

Background: Sickness absence (SA) due to common mental disorders and musculoskeletal pain is highly prevalent worldwide and has increased markedly over the past decade. Mental and behavioral disorders account for more incapacity benefit claims than any other disorder. Evidence-based interventions such as cognitive behavioral therapy for depression and anxiety have proven to be effective treatments for these patient groups, however the effect on SA duration and return to work (RTW) is unclear. Overall, there is a lack of knowledge on how to treat patient in order to have satisfactory results for both symptoms and RTW.

Purpose and aims: The purpose of this doctoral project was to evaluate the effect of psychological interventions on SA and RTW. The first aim was to identify published randomized controlled trials and evaluate the effect on SA in a systematic review and meta-analysis. The second aim was to investigate the effects and cost-effectiveness of Acceptance and Commitment Therapy (ACT) and the Workplace Dialogue Intervention (WDI) both separately and combined compared with treatment as usual (TAU).

Methods: In study I, a systematic review and meta-analysis was conducted to evaluate the effect of psychological treatment on duration of SA and symptoms in patients on SA due to common mental disorders or musculoskeletal pain. In study II, patients (N = 352) were randomized to one of four groups, ACT, WDI, ACT+WDI, or TAU, and were followed up until one year after randomization regarding net SA days, work ability, level of function, satisfaction with life, and psychiatric symptoms. Study III was an economic evaluation of the same sample as in study II, consisting of a cost analysis and a cost-utility analysis from a health-care perspective and a limited societal perspective. In study IV, long-terms effects on outcome and economic evaluation were evaluated with a two-year time horizon.

Results: In study I, 30 studies matched inclusion criteria and was included in the analysis. The metaanalysis yielded a significant but small effect size in favor of psychological treatments regarding duration of SA. There were no significant effects for symptoms of anxiety or depression. The results from study II showed no significant differences between groups over time for net SA days or work ability. Diagnostic group moderated the results. Patients with exhaustion disorder had more SA days in ACT+WDI compared with TAU and depressed patients had more SA days in WDI compared with TAU. For symptoms of depression, anxiety and exhaustion disorder, there were significant interaction effects in favor of ACT and ACT+WDI from pre- to post measurement when compared with TAU. The economic evaluation in study II showed that all groups reported significant improvements in healthrelated quality of life (HRQoL), but there were no significant differences between groups in HRQoL or costs. ACT was deemed cost-effective from a health-care perspective and the probability of cost-effectiveness for ACT+WDI compared with ACT was 50%. WDI and TAU were rejected due to less economic efficiency. In study IV, there were no differences between groups in terms of SA, work ability or symptoms of anxiety or depression. In the WDI group, participants with depression had more SA days compared to those with exhaustion disorder. The economic evaluation confirmed the results from the one-year follow-up.

Conclusions and further directions: Evidence-based psychological treatments such as CBT is effective for treating symptoms of common mental disorders but the effect on SA duration and RTW is unsatisfactory. There is a great need for further development of return to work interventions and more well-designed intervention trials. Generally, study quality was low which introduces further doubt in the interpretation of the results. There were overall few differences between ACT, WDI, and ACT+WDI compared with TAU. Effects in terms of cost-effectiveness were also small, probably due to lack of treatment effects. There are many areas in need of further development and evaluation in sickness absence research. Interventions needs to be more specific in terms of theory, mechanisms of change and tailored to maximize effects for different subgroups.

List of scientific papers

I. Finnes, A., Enebrink, P., Ghaderi, A., Dahl, J., Nager, A., & Öst, Lars-Göran. Psychological treatments for return to work in individuals on sickness absence due to common mental disorders or musculoskeletal pain: a systematic review and meta-analysis of randomized controlled trials. [Submitted]

II. Finnes, A., Ghaderi, A., Dahl, J., Nager, A., & Enebrink, P. (2017). Randomized Controlled Trial of Acceptance and Commitment Therapy and a Workplace Intervention for Sickness Absence Due to Mental Disorders. Journal of Occupational Health Psychology.
https://doi.org/10.1037/ocp0000097

III. Finnes, A., Enebrink, P., Sampaio, F., Sorjonen, K., Dahl, J., Ghaderi, A., Nager, A., Feldman, I. (2017). Cost-Effectiveness of Acceptance and Commitment Therapy and a Workplace Intervention for Employees on Sickness Absence due to Mental Disorders. Journal of Occupational and Environmental Medicine.
https://doi.org/10.1097/jom.0000000000001156

IV. Finnes, A., Sorjonen, K., Ghaderi, A,. Dahl, J., Nager, A., Enebrink, P. Efficacy and Cost-effectiveness of Acceptance and Commitment Therapy and a Work-place Intervention – Two-year follow-up of a randomized controlled trial. [Manuscript]