Prevention of sick leave at the workplace: design of a cluster-randomized controlled trial of a problem-solving...

Common mental disorders are highly prevalent in the working population, affecting about 1 in 5 persons in the Organisation for Economic Co-operation and Development countries. About 30% of those affected have a first period of sick leave. Despite several attempts to reduce the risk of sick leave among employees with common mental disorders, there is a lack of knowledge about effective, preventive interventions which aim to reduce such risks. This protocol describes the design of a study to evaluate the effectiveness of a problem-solving intervention delivered by first-line managers to employees with common mental disorders on the prevention of sick leave during the 12-month follow-up.

The study applies a two-armed cluster-randomized trial design of a problem-solving intervention conducted in private-sector companies. First-line managers are randomized into intervention- or control groups by computer-generated random numbers, allocation ratio 1:1. Employees are eligible if at risk for future sick leave due to common mental disorders. These are identified by self-reported psychological health measured by the General Health Questionnaire 12-item, cut-off ≥3, or a positive answer to risk of sick leave. The intervention is based on problem-solving principles. It involves the training of the first-line managers who then deliver the intervention to employees identified at risk of sick leave. First-line managers in the control group receives a lecture. Primary outcome is number of registered days of sick leave due to common mental disorders during the 12-month follow-up. Secondary outcomes are general health, psychological symptoms, work performance, work ability and psychosocial work environment. A process evaluation will examine the intervention's reach, fidelity, dose delivered, dose received, satisfaction and context. Research assistants managing the screening procedure, outcome assessors and employees are blinded to randomization and allocation.

The study includes analyses of the intervention's effectiveness and an alongside process evaluation. Methodological strengths and limitations, for example the risk of selection bias, attrition and risk of contamination are discussed.

Clinicaltrials.gov NCT04975750 Date of registration: 08/16/2021.