Abstract: We included six trials, four of which took place in the USA. Four trials employed randomised controlled trial (RCT) designs. Trials were conducted in workplaces from the manufacturing, industrial and services-based sectors. The sample sizes of workplaces ranged from 12 to 114. Workplace policies and practices targeted included: healthy catering policies; point-of-purchase nutrition labelling; environmental supports for healthy eating and physical activity; tobacco control policies; weight management programmes; and adherence to guidelines for staff health promotion. All implementation interventions utilised multiple implementation strategies, the most common of which were educational meetings, tailored interventions and local consensus processes. Four trials compared an implementation strategy intervention with a no intervention control, one trial compared different implementation interventions, and one three-arm trial compared two implementation strategies with each other and a control. Four trials reported a single implementation outcome, whilst the other two reported multiple outcomes. Investigators assessed outcomes using surveys, audits and environmental observations. We judged most trials to be at high risk of performance and detection bias and at unclear risk of reporting and attrition bias. Of the five trials comparing implementation strategies with a no intervention control, pooled analysis was possible for three RCTs reporting continuous score-based measures of implementation outcomes. The meta-analysis found no difference in standardised effects (standardised mean difference (SMD) −0.01, 95% CI −0.32 to 0.30; 164 participants; 3 studies; low certainty evidence), suggesting no benefit of implementation support in improving policy or practice implementation, relative to control. Findings for other continuous or dichotomous implementation outcomes reported across these five trials were mixed. For the two non-randomised trials examining comparative effectiveness, both reported improvements in implementation, favouring the more intensive implementation group (very low certainty evidence). Three trials examined the impact of implementation strategies on employee health behaviours, reporting mixed effects for diet and weight status (very low certainty evidence) and no effect for physical activity (very low certainty evidence) or tobacco use (low certainty evidence). One trial reported an increase in absolute workplace costs for health promotion in the implementation group (low certainty evidence). None of the included trials assessed adverse consequences. Limitations of the review included the small number of trials identified and the lack of consistent terminology applied in the implementation science field, which may have resulted in us overlooking potentially relevant trials in the search. Available evidence regarding the effectiveness of implementation strategies for improving implementation of health-promoting policies and practices in the workplace setting is sparse and inconsistent. Low certainty evidence suggests that such strategies may make little or no difference on measures of implementation fidelity or different employee health behaviour outcomes. It is also unclear if such strategies are cost-effective or have potential unintended adverse consequences. The limited number of trials identified suggests implementation research in the workplace setting is in its infancy, warranting further research to guide evidence translation in this setting.

Plain-language summary: We looked for studies that compared strategies to support the implementation of health-promoting policies and practices in workplaces versus either no implementation strategy or different implementation strategies. Implementation strategies could include quality improvement initiatives, education, and training, among others. They could target policies or practices directly instituted in the workplace (e.g. workplace healthy catering policy), as well as workplace-led efforts to encourage the use of external health promotion services (e.g. employee gym membership subsidies). We found six eligible studies that investigated these strategies. Most took place in the USA, and workplaces were in the manufacturing, industrial and services-based sectors. The number of workplaces examined in the studies ranged from 12 to 114. Implementation strategies in the six studies targeted different workplace policies and practices: healthy catering; point-of-purchase nutrition labelling; environmental prompts and supports for healthy eating and physical activity; tobacco control policies; sponsorship of employee weight management programmes; and adherence to national guidelines for staff health promotion. All studies used multiple strategies to improve the implementation of these policies and practices, including: educational meetings, interventions tailored to the specific needs of the workplace, and workplace consensus processes to implement a policy or practice. Four studies compared implementation strategies versus no intervention, one study compared different implementation strategies, and one study compared two implementation strategies with each other and a control. Researchers used surveys, audits and observations in workplaces to evaluate the effect of the strategies on the implementation of workplace policies and practices. The evidence is current to 31 August 2017. When we combined findings from three studies, we did not find any difference in the level of implementation of health-promoting policies or practices between workplaces that received implementation strategy support versus those that did not, indicating that these strategies may make little to no difference. In the two trials comparing different implementation strategies, both reported improvements in implementation, favouring the more intensive implementation support group. Findings for effects on employee health behaviours were inconsistent and based on very low to low certainty evidence, so it is unclear whether the implementation strategies improved these outcomes. One of the included studies reported on cost, and none on the unintended adverse consequences of implementation strategies. There were few included studies, and they used inconsistent terminology to describe implementation strategies, limiting the strength of the evidence. We rated the certainty of the evidence as low for the effect of implementation strategies on policy and practice implementation, based on four randomised studies (where groups are randomly assigned to different study groups), and very low based on two non-randomised studies. We also graded evidence on employee health behaviours and cost outcomes as low and very low. The findings of the review do not provide clear evidence regarding the impact of implementation strategies on workplace health-promoting policy and practice implementation or on employee health behaviours. Further research is needed.