Introduction The health care system of Denmark is currently undergoing major centralizations. Relocation of workplaces as well as mergers and split-ups may impact both health and productivity among employees and managers. The unification of all hospital units in Aarhus, Denmark, poses an opportunity to study the short- and long-term consequences of different degrees of organizational change during a fixed event.

Objectives The primary aims are to: 1) investigate the consequences of major organizational changes on absenteeism and mental health of employees and workplace productivity and staff turnover, and 2) identify risk factors for negative consequences on mental health, sickness absence, productivity, and staff turnover, in order to identify risk groups for targeted prevention.

Methods Using national and regional registers we will establish a cohort of 10,000 individuals employed at Aarhus University Hospital in the period from 2011–2020. Hospital units moving at different time points through 2016–2019 will be aligned on the index date defined by their relocation and followed up to 5 years after and prior to this.

Results Based on the life event literature we expect to find a delayed effect of major organisational change on sickness absence and mental health, and an immediate effect on staff turnover and productivity. We hypothesize these effects as more pronounced for units which in addition to relocating also merge/split, representing greater organisational change. We also expect to identify risk factors for the chosen outcomes based on job titles, age, seniority, and work unit characteristics such as number of employees, patient centred vs. service/administrative, and out-patient vs. in-patient wards.

Conclusion This project is expected to produce valuable knowledge about the mental health and/or economic consequences of major organizational changes in the health care system. This can inform preventive actions targeting specific employee groups in future centralization projects.