Characteristics of interventions and comparisons.

RTW = return to work, n.r. = not reported, OP = occupational physician, PT = physical therapist, GP = general practitioner, rehab. = rehabilitation.1The trial compared three intervention arms with usual practice. We considered only the arm “combined intervention” because the other arms were restricted to either workplace or health care interventions.2In the Dutch system, each company is obliged to have company insurance for sick leave and to offer their employees access to occupational health care. Occupational physicians provide social-medical guidance for sick listed employees with the aim to return to work (RTW) as quickly as possible. Usually, occupational physicians are organised as third party service providers.3From personal correspondence.