Gärtner 2013.

Study characteristics
Methods	Cluster‐RCT, the Netherlands
Participants	Nurses on wards of an academic hospital were screened for work and health problems: Experimental: 29 wards, 591 participants of which 151 screened positive. Control: 28 wards, 561 participants of which 161 screened positive. Experimental: 17%, Control 22% men, > 45 years age ‐ Experimental 51% Control 46%, > 10 years of experience ‐ Experimental 51% Control 41%
Interventions	1) Experimental 1: all who screened positive were referred to Occupational Health Physician (OHP). Participants who were screened as positive were invited for a face‐to‐face preventive consultation with their occupational physician. The consultation was voluntary, and workers could reschedule or cancel it if they wished. Supervisors were not informed about the screening results or about the invitation for and content of the preventive consultation of any employee. The 7‐step protocol for OHPs closely followed occupational physicians’ care as usual for consultations initiated by the employee in contrast to the compulsory consultation in the context of absenteeism. Occupational physicians received 3 hours of training from the researchers on the use of the protocol. (CBT) 2) Experimental 2: participants received personalised feedback on their screening results immediately after filling out the baseline questionnaire, both onscreen and in an e‐mail. The personalised feedback was followed by an invitation for a tailored offer of self‐help EMH interventions, on the basis of an algorithm based on the specific symptoms and the work‐relatedness of the symptoms. participants were mostly offered a choice of 2 to 3 EMH interventions to leave room for personal preferences. Participants who screened negative on all mental health complaints were invited to follow an EMH intervention aimed at enhancing and retaining their mental fitness. The EMH interventions are self‐help interventions on the Internet aimed at reducing specific mental health complaints or enhancing well‐being. The interventions are mainly based on the principles of cognitive behavioural therapy and combine a variety of aspects, e.g. providing information and advice, weekly assignments, the option of keeping a diary and a forum to get in contact with others who have similar complaints. The EMH interventions were developed as stand‐alone interventions by the Trimbos Institute (CBT). 2) Control: waiting list: In the control arm. Participants filled out the baseline questionnaire; however, results of the screening‐questionnaires were not to be reported back to participants, and no further interventions were advised at baseline. As compensation, participants in the control arm received their personal screening results together with a tailored choice for a self‐help EMH intervention six months after baseline.
Outcomes	Gartner 2013: the study's primary outcome was help‐seeking behaviour; we used secondary outcomes: distress from the Dutch 4DKL, anxiety and depression from Brief Symptom Inventory Ketelaar 2013: the study used work‐functioning as the primary outcome: we used the distress part of the Dutch 4DKL as stress outcome; anxiety and depression were also measured but not reported Bolier 2014: Brief Symptom Inventory (BSI) ‐ Anxiety and Brief Symptom Inventory (BSI) ‐ depression Noben 2014: cost‐effectiveness
Identification
Notes	We got the following data for the distress scale of the 4DKL at 6 months follow‐up for the group who screened positive from author K Nieuwenhuijsen: Experimental: N = 86 6.24 ± 6.52 Control: N = 116 6.82 ± 6.57 We got the following data from author S. Ketelaar: Distress measure with 4DKL at 6 months follow‐up for the group who screened positive: Experimental: N = 52 6.06 ± 6.54; Control: N = 116 6.82 ± 6.5.7 4DKL included in analysis 1.2 Intervention groups combined to create a single pair‐wise comparison. BSI‐depression included in analysis 1.4 Experimental 2 vs control  4DKL included in analysis 5.2 Experimental 1 vs Experimental 2
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	" Randomization was performed at the ward level (n = 86). Randomization sequences with a block size of three were generated with Nquery Advisor (Statistical Solutions, Ltd, Cork, Ireland) by one researcher (K.N.) who was not involved in the recruitment"
Allocation concealment (selection bias)	Unclear risk	Not blinded
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Participants were not blinded whereas outcomes are self‐reported.
Incomplete outcome data (attrition bias) All outcomes	High risk	At 3 months lost to follow‐up: Experimental 37% / Control 30%; at 6 months Experimental 46% / Control 34%
Selective reporting (reporting bias)	Low risk	Gartner 2013: All outcomes reported that were announced in protocol Ketelaar 2013: Anxiety and Depression were not reported in Ketelaar 2013 but in Bolier 2014
Other bias	Unclear risk	Compliance very low: 34% of those invited visited their OHP