Prevention of sick leave at the workplace: design of a cluster-randomized controlled trial of a problem-solving intervention among employees with common mental disorders

Information about the study’s aim and design is provided to the steering groups at each company by the principal investigator (EBB).

To be eligible for participation an employee must be at risk for future sick leave due to CMDs. Employees at risk are identified by a web-based screening questionnaire, administrated by a research assistant to all employees whose first-line managers have been included and randomized. The following health and sick leave measures will be screened by the web-based questionnaire;

Self-reported psychological health is measured by the validated General Health Questionnaire (GHQ) 12-item, Swedish version [26]. The items include aspects reflecting different symptoms primarily related to depression but also general anxiety symptoms, for example stress, and further ability to perform daily activities and coping with everyday problems. Six items are positively worded and six items negatively. The time period assessed is the past few weeks. Every item has a four-category response format, namely “better than usual”, “same as usual”, “less than usual” and “much less than usual” [26, 27]. The traditional scoring method (all items are coded 0–0–1-1) will be used. Individuals scoring ≥3 are categorized as at risk for sick leave due to CMDs. This cut-off has previously been used in the Swedish Public Health Agency’s national surveys [28].

Sick leave risk is measured by a single question, developed by the research group: “About your health – do you think you will receive sick leave benefits because of stress, anxiety or depression in the coming 12 months?”. The response format is a 4-point scale, ranging from “Yes, most likely”, “yes, quite likely”, “I’m not sure”, “no, probably not”. The employee’s own beliefs and/or expectations about future sick leave have been shown to predict sick leave [4, 29].

The first-line managers take part in a 1 ½ days training course. The training course is provided by a licensed psychologist (BJ) with extensive experience of problem-solving therapy, manager coaching and supervising health care professionals, and the principal investigator (EBB) who also has a thorough knowledge of problem-solving interventions.

The training is based upon interactive and didactic principles, as recommended by Forsetlund et al. [31]. The training includes didactic features (lectures, reading about problem-solving) and participative sessions that provide the opportunity to practice skills (role-play, observations of others role-play, discussions). The first-line managers receive a manual and worksheets for the intervention [14, 32]. In the current project the manual and worksheets have been adapted for use by first-line managers, because they are not expected to have professional training in e.g. communication skills and/or identifying signs of depressive symptoms. The first-line managers will be trained in conversation and communication with focus on: general communication skills, i.e. to listen actively and attentively (use eye contact with the employee, nod, show that you are listening); encouraging the employee to talk and summarize and check your understanding of what has been said; observing and describing the employee’s feelings without judgment [33]. In addition, the first-line managers receive information about validation of communication, which is about communicating an understanding of the other person’s feelings and thoughts [34]. This form of communication does not necessarily mean agreement; it is rather used as a means to acknowledge and legitimize the other person’s experience, which in turn may increase the likelihood that he or she will feel understood. This may result in building trust, reducing emotional intensity and de-escalating possible conflict [35]. We understand some degree of validation to be a beneficial aspect of any type of successful communication, and especially with employees who are at risk of CMDs. These employees may present with some level of emotional vulnerability. Validating communication on the part of the first-line manager may prevent adding further to this vulnerability. If the communication is dis-validating it could confound the effects of the problem-solving. This part of the training is therefore seen as a prerequisite for successful problem-solving.

Between the first and second training sessions, the managers are expected to complete one or two learning assignments. Opportunities and difficulties regarding using the steps of the problem-solving procedure or other aspects of their meetings with the employee are discussed. Common difficulties encountered in the course of the problem-solving intervention, such as defining problems and brainstorming about solutions [36], will be specifically addressed. In addition, the first-line managers are encouraged to use problem-solving whenever possible.

In addition to the training, the first-line managers will be invited to two web-based booster sessions in the first 8 weeks after the training. These sessions include supervision and feedback about the first-line managers’ use of the problem-solving intervention and are based on the first-line managers’ reported cases and/or difficulties. The sessions are led by the licensed psychologist (BJ) and the principal investigator (EBB).

The first-line managers randomized to the control group will receive a 3-h lecture which includes a brief overview of worker health, work stress and the mismatch model [37]. The information includes protective and risk factors in the work environment in relation to occupational stress and CMDs. Basic information about the importance of self-efficacy for mental health is given, and different ways of interacting with and supporting employees with CMDs are reflected upon. The lecture also includes advice about communication, with focus on general communication skills: listen actively and attentively; encouraging the employee to talk; summarizing and checking your understanding of what has been said; observing and describing the employee’s feelings without judgment [33].

The primary outcome is the total number of days of sick leave due to CMDs during the 12-month follow-up. Data will be collected for individuals from the participating companies’ (employers’) registers (covering the first 14 calendar days of sick leave) and from the MiDAS register (sick leave ≥15 days) covering part-time (defined as 25, 50 or 75% of full-time) and full-time. Sick leave due to diagnoses other than CMDs will also be included. Data will be collected from baseline until the 12-month follow-up and for the 24 months preceding baseline. The primary outcome is based on data from the employers’ and MiDAS registers, limiting missing values during follow-up.

Self-rated general health is measured with a single item from the Short-Form Health Survey with 5-point response anchors, from (1) “excellent” to (5) “bad” [39]. The presence and severity of depression (7 items) and anxiety (7 items) are assessed by the validated Hospital Anxiety and Depression Scale, which is a 14-item self-reported questionnaire [40, 41]. The response format is a 4-point scale, ranging from 0 (not at all) to 3 (nearly all the time), with higher scores indicating higher levels of depression and anxiety. Self-reported exhaustion will be assessed by four items of the self-rated exhaustion disorder (s-ED) scale [42], that has demonstrated construct and predictive validity. The response format is yes/no [42]. Work stress is measured by a single item with a 5-point response scale, ranging from (1) “not at all” to (5) “very much” [43], administered as a text message.

Work performance impairment will be evaluated by two items administered as text messages: one item about impairment of work performance due to health problems (presenteeism), and one item about work environment problems. These items have been developed, modified and validated [44] and were inspired by the Work Productivity Activity Impairment questionnaire [45]. The first item, impairment of work performance due to health problems, is assessed by the following question: “During the past four weeks, how much did your health problems affect your performance while you were working?”. The respondents are asked to rate how their health-problems affect their work performance on a scale ranging from 0 indicating that health problems had no effect on their work, to 10, indicating that health problems hindered them from working at all. The second item about work-environment problems is measured by the question: “During the past four weeks, how much did work environment problems affect your performance while you were working?”. The response format is a scale ranging from 0 to 10, with higher scores indicating that work environment problems prevented respondents from working. The items have been tested in a Swedish setting and shown reliable psychometric properties (test-retest ICCs with 95% CIs for health related and work-environment production loss, respectively: 0.90, (CI; 0.74–0.98); 0.91, (CI; 0.79–0.98)) [46].

Work ability will be measured by three items of the Work Ability Index [47]. Two items refer to perceived work ability in relation to the physical and mental demands of the work. The response format is a five-point scale, ranging from “very bad” to “excellent”. The third item assesses the employee’s own beliefs about his/her work ability: “Do you believe that – from the standpoint of your health – you will be able to do your current job two years from now?” with response format “unlikely”, “not certain”, “relatively certain” [47].

The Copenhagen Psychosocial Questionnaire (COPSOQ) III, Swedish standard version [48], is used for assessing demands at work by quantitative and emotional demands. Interpersonal relations and leadership are assessed by recognition and quality of leadership; work-individual interface is measured by commitment to the workplace and work-life conflict. These scales are measured at baseline and at 6- and 12-month follow-up. The response format is a Likert scale with five levels (0, 25, 50, 75, 100), with higher scores indicating higher work demands, better interpersonal relations and leadership, and for the work-individual interface, higher scores indicate better commitment to the workplace and worse work-life conflict.

The impact of private life on work is measured by the single item: “Do the demands of your family or spouse/partner interfere with your work-related activities?” from the General Nordic Questionnaire [49, 50] with the response anchors “Very seldom or never” to “Very often or always”.

General self-efficacy measures the employee’s belief in his/her ability to cope with the current situation, to mobilize motivation and act upon demands in different situations. It is positively correlated with mental work capacity. In this study, general self-efficacy is included to clarify how the intervention is working and is measured by a Swedish-validated version of the General self-efficacy scale [51], at baseline and at 6- and 12-month follow-up. Responses are given on a four-point Likert scale ranging from (1) “not at all true” to (4) “exactly true”. A validated single-item measure of self-efficacy is also used: “I am confident in my ability to solve problems that I might face in life”. The response format is a ten-point scale from (1) “totally disagree” to (10) “totally agree” [52].

In addition, problem-solving might lead to a better perception of influence at work, and manager support, measured by COPSOQ III subscales Influence at work, and Social support from supervisor [48]. Influence at work is assessed by four questions of Influence at work scale (e.g. Do you have any influence over what you do at work?). Manager support is assessed by two questions of the social support from supervisor scale (e.g., How often is your immediate superior willing to listen to your problems a work, if needed?).

A variety of prognostic factors for the risk of future sick leave due to CMDs will be measured. Employees’ personal characteristics (e.g. age, gender, marital status, educational level, profession) and workplace characteristics (e.g. sector) will be collected from the baseline questionnaire and the LISA and MiDAS registers.

Employees’ psychosocial safety climate (PSC) will be measured at baseline. PSC focuses on the senior management’s role in creating a healthy work environment and refers to the employees’ perceptions of the organization’s psychosocial health climate, e.g. guidelines, practices and procedures used to establish and maintain a psychosocial safe and sound work environment [53]. Further, the concept reveals whether the senior management supports stress prevention at work. The four-item version of the valid and reliable Psychosocial Safety Climate [54] will be used, using a 5-point scale ranging from (1) “strongly disagree” to (5) “strongly agree”. Average scores > 12 indicate good occupational safety and health [55].

Information about workplace adjustments (e.g. changes in work tasks, working hours, change of department) and co-interventions (e.g. psychological counselling, and if so, number of sessions, use of antidepressants, general health care consumption, contact with the occupational health service) will be collected from the employees at baseline and at 6- and 12- month follow-up.

The first-line managers’ personal characteristics (e.g. age, gender, marital status, education) and workplace characteristics (e.g. sector, profession, number of employees, leadership network, leadership training) will be collected. In addition, the first-line managers’ self-efficacy (single item), problem-solving confidence [56], leadership support or supervision, and perceived ability to support employees with CMD, will be measured at baseline and after 12 months.

By sampling 38 clusters (19 clusters in the intervention arm and control arm respectively) with an average of three employees in each cluster, the study population is estimated to be a total of 114, with 57 employees in the intervention group and the control group respectively. With these numbers it will be possible to achieve about 80% power to detect a difference of 30% in number of days of sick leave during the 12-month follow-up, assuming that the mean number of days in the control group is 108 [14]. The standard deviation of sick leave days was 60 days [10]. The intra-cluster correlation was set to 0.015 and a significance level of 0.05, two-sided test.