Towards a Sustainable Work Force in the Healthcare Sector for the 21st Century: Health-promoting Work Schedules (HeWoS)

Aims This is a two-arm cluster randomized controlled trial that assesses the consequences of a shift work schedule without quick returns for six months, compared to a schedule that include quick returns. First, we will examine any differential change in sickness absence, during the six-month intervention period. Second, we will examine if there are differential changes in sleep and functioning, physical and mental health, work-related accidents, and turnover intention, among others. Third, we will investigate if individual characteristics associated with shift work tolerance including sex, age, personality and subjectively reported sleep need will moderate the negative effects of quick returns on the primary and secondary outcomes. Finally, the study will investigate if individual factors like satisfaction with work schedule, job satisfaction, job engagement and work-family interference will moderate the negative effects of quick returns on the primary and secondary outcomes.

Research design A cluster randomized controlled trial comparing a work schedule abolishing quick returns (intervention) with that of a work schedule maintaining a normal amount of quick returns (control) will be conducted. The clusters represent hospital units that are randomly selected to receive (or not receive) the intervention. 'Normal amount of quick returns' refer to that which is the common practice at the respective hospital unit in recent years (i.e., when no explicit changes have been made to the work schedule), which means that the total number of quick returns at the unit will vary from 329-2356 per year. The hospital units were randomized to one of the two conditions in September 2020, of which the autumn of 2020 was spent planning the shift schedule for 2021 (i.e., removing quick returns for the intervention group and leaving quick returns untouched for the control group), with the intervention period commencing from February/March 2021 for most units. The intervention period in this study is six calendar months. Most units in this trial start the intervention period in February/March 2021, but some units will, for practical reasons, start the intervention period in the second half of the rotation year, i.e. from August/September 2021 or later.

The primary outcome is sickness absence retrieved from the local records kept by the hospital (including short- and long-term sick leave). The baseline measurements will be sickness absence from the year preceding the intervention, which for each individual participant will be matched on duration and season to that of the intervention period. Sickness absence data will be retrieved from the local records kept by the hospital (Vedaa, Pallesen et al. 2017). This record includes information about the date of any absence of the individual employee, implying that it includes information about both short- and long-term sickness absence. Further, these data include information on whether the absence is self-certified or whether it is certified by a physician, whether the absence is due to a sick child of whom the employee has caretaker responsibility of, and whether the absence is due to COVID-19 related issues (e.g., quarantine). The use of register data will not require individual consent. However, a consent-based part of the trial will also be conducted, in which secondary outcome measures will be collected via questionnaire at baseline and six-month follow-up. All employees (n ≈ 4000) at the randomized units will be asked to complete a digital questionnaire made available via the hospital's internal website. Baseline assessment will occur prior to the intervention period, and follow-up assessment will occur towards the end of the intervention period. A subsample (n ≈ 50) will be asked to objectively record their sleep with advanced radar technomogy (Somnofy™) and subjectively with sleep diaries for ≥1 week at the baseline and follow-up assessments, respectively.

Participants and procedure Recruitment This trial is carried out in close collaboration with the human resources department at Haukeland University Hospital. All hospital care units that have 24-hour staffing at the hospital will be randomized, in which all healthcare workers working shifts will be included, with the exception of physicians. Physicians will not be included since they often have a different shift schedule and compensation scheme compared to the other occupational groups. Hereinafter, 'all employees' refer to all healthcare workers engaged in shift work at the randomised hospital units, with the exception of physicians. All employees (n ≈ 4000) at the randomized hospital units will be asked to complete a questionnaire prior to and at the end of the intervention period. Recruitment for this part of the trial will take place via the hospital's internal website. Researchers and human resources personnel at the hospital will attend staff meetings at all included units to inform about the research project and encourage participation. A subsample of n ≈ 50 randomly selected employees (evenly distributed from the intervention and the control units) will be recruited for the sleep monitoring section of the trial.

Randomisation and masking The randomization in this trial occurred at the cluster level, in which hospital units constituted the clusters. Hospital units can vary in terms of how much staff they need over the 24-hour day, hence, the work schedule and the occurrence of, for example, quick returns and night shifts can vary across the units. Similar units were therefore grouped together based on the fact that they shared some attributes or characteristics. Then a stratified randomization was performed to the two study conditions in a 1: 1 ratio. One subgroup could, for example, consist of units with emergency functions, another with intensive care functions, one with mental health care, and one with maternity care, etc. In total we had 10 strata and the sizes of each stratum varied between 2 and 19 hospital units. The randomization list for each stratum was generated by the online randomization webpage, www.randomization.com, and the list for each stratum was saved.