Effectiveness of the interventions against workplace violence suffered by health and support professionals: A meta-analysis.

Objective: to assess the effectiveness of the interventions targeted at preventing and reducing the workplace violence suffered by health and support professionals.
Method: a systematic review with meta-analysis conducted in eight databases and in the gray literature. Risk of bias was assessed by means of the Cochrane tools and certainty of the evidence, through Grading of Recommendations Assessment, Development and Evaluation. The analysis was performed in a descriptive manner and through the meta-analysis, including a heterogeneity assessment.
Results: a total of 11 randomized and quasi-randomized studies were eligible, of which six (54.5%) implemented individual skills, four used a multiple approach (36.4%) and one (9.1%) resorted to governmental actions. Four studies (36.4%) exerted a positive and significant effect on reducing violence. Risk of bias was classified as high or uncertain. The meta-analysis was performed with two studies that tested individual skill (intervention group) versus individual skill (comparator group), although there was no scientific evidence (95% CI: -0.41 - 0.25, p=0.64) for the violence prevention/reduction outcome.
Conclusion: this review did not obtain a high level of evidence in the prevention or reduction of workplace violence. The reduced number of randomized trials, the lack of studies with low risk of bias and the high consistency may have been factors that hindered recommending effective interventions.