Our systematic review provides the evidence base supporting that workplace-based RTW interventions can reduce work disability duration and associated costs, however the evidence regarding their impact on quality-of-life outcomes was much weaker.

Interdisciplinary research needs to develop a comprehensive conceptual framework. Priority should be given to studies on specific domains of risk factors meeting five selection criteria: amenability to change; relevance to users of research; generalizability across health conditions, disability phases, and settings; "degree of promise" as derived from qualitative exploratory studies; and capacity to improve measurement instruments. Combining qualitative and quantitative research methods is necessary to bridge existing knowledge gaps.

Although the overall quality of systematic reviews was satisfactory, the quality of the individual papers included in the reviews varied considerably. The reviews often provided contradictory evidence on the effectiveness of a wide range of commonly used conservative interventions for chronic nonspecific low back pain. These findings illustrate the pitfalls of systematic reviews where there are a number of low-quality trials and underscore the need for high-quality primary trials that will allow for more conclusive reviews.

There was no advantage from the program compared with usual care on the outcomes measured-a finding consistent with recent studies that examined the longer-term effectiveness of other interventions in the first few weeks of back pain symptoms.