Verdes Montenegro Atalaya 2021.

Study characteristics
Methods	Study design: cluster‐randomised controlled trial Study grouping: parallel group
Participants	Baseline characteristics Experimental group 1: MRBS 4 weeks Age (mean ± SD): 47.7 ± 13.7 Sex (N (% female)): 18 (75%) Sample size: 24 Years of experience (mean ± SD): 19.5 ± 13.9 Experimental group 1: MRBS 8 weeks Age (mean ± SD): 35.7 ± 12 Sex (N (% female)): 28 (76%) Sample size: 37 Years of experience (mean ± SD): 8.9 ± 11 Control: no intervention Age (mean ± SD): 40.3 ± 13 Sex (N (% female)): 40 (78%) Sample size: 51 Years of experience (mean ± SD): 13.1 ± 13 Overall Age (mean ± SD): 41.6 ± 12 Sex (N (% female)): 86 (76.8) Sample size: 112 Years of experience (mean ± SD): 12.9 ± 13.2 Included criteria: NR Excluded criteria: NR Pretreatment: At baseline, statistically significant differences were found between the three groups in age, professional type, and work experience. Compliance rate: NR Response rate: NR Type of healthcare worker: various types of healthcare workers
Interventions	Intervention characteristics Experimental group 1: MRBS 4 weeks Type of the intervention: Intervention type 1 ‐ to focus one’s attention on the experience of stress Description of the intervention: MBSR training program complemented with practices of the Mindful Self‐Compassion (MSC) program The number of sessions: 4 Duration of each session on average: 2.5 hours Duration of the entire intervention: 4 weeks Duration of the entire intervention short vs long: short Intervention deliverer: NR Intervention form: group Experimental group 1: MRBS 8 weeks Type of the intervention: Intervention type 1 ‐ to focus one’s attention on the experience of stress Description of the intervention: MBSR training program complemented with practices of the Mindful Self‐Compassion (MSC) program The number of sessions: 8 Duration of each session on average: 2.5 hours Duration of the entire intervention: 8 weeks Duration of the entire intervention short vs long: short Intervention deliverer: NR Intervention form: group Control: no intervention Type of the intervention: NA Description of the intervention: NA The number of sessions: NA Duration of each session on average: NA Duration of the entire intervention: NA Duration of the entire intervention short vs long: NA Intervention deliverer: NA Intervention form: NA
Outcomes	PSQ Outcome type: ContinuousOutcome
Identification	Sponsorship source: NR Country: Spain Setting: Spanish National Health System teaching units Comments: NR Authors name: Juan Carlos Verdes‐Montenegro‐Atalaya Institution: Family and Community Medicine Teaching Department of Burgos, 0 Email: juancarlosverdesm@yahoo.es Address: Family and Community Medicine Teaching Department of Burgos, 09006 Burgos, Spain Time period: NR
Notes	PHQ included in analysis 1.1. Intervention groups combined to create a single pair‐wise comparison
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Each TU was considered as a different and independent cluster, randomly assigned to the CG (2 TUs) or one of the two EGs (4 TUs)." Insufficiently described.
Allocation concealment (selection bias)	Unclear risk	Quote: "EG1 participants were included in a standard training program of mindfulness and self‐compassion; while EG2, in an abbreviated one. Furthermore, the participants from each TU were stratified according to the type of professional (66 tutors versus 66 resident intern specialists)." Insufficient information to understand whether intervention allocations could have been foreseen in advance of, during, enrolment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants 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	Low risk	53 of the 165 (32%) randomised participants lost to follow‐up. Reasons provided. The baseline characteristics of participants who dropped out of the study were similar to those who completed it, so systematic selectionbias is unlikely.
Selective reporting (reporting bias)	Unclear risk	No trial registration or no study protocol reported nor did we find one online
Other bias	Unclear risk	Statistically significant differences were observed between the three groups in age, type of professional, and time working in the Spanish National Health System