Local opinion leaders: effects on professional practice and healthcare outcomes

Clinical practice is not always evidence-based and, therefore, may not optimise patient outcomes. Local opinion leaders (OLs) are individuals perceived as credible and trustworthy, who disseminate and implement best evidence, for instance through informal one-to-one teaching or community outreach education visits. The use of OLs is a promising strategy to bridge evidence-practice gaps. This is an update of a Cochrane review published in 2011.To assess the effectiveness of local opinion leaders to improve healthcare professionals' compliance with evidence-based practice and patient outcomes.We searched CENTRAL, MEDLINE, Embase, three other databases and two trials registers on 3 July 2018, together with searching reference lists of included studies and contacting experts in the field.We considered randomised studies comparing the effects of local opinion leaders, either alone or with a single or more intervention(s) to disseminate evidence-based practice, with no intervention, a single intervention, or the same single or more intervention(s). Eligible studies were those reporting objective measures of professional performance, for example, the percentage of patients being prescribed a specific drug or health outcomes, or both. We included all studies independently of the method used to identify OLs.We used standard Cochrane procedures in this review. The main comparison was (i) between any intervention involving OLs (OLs alone, OLs with a single or more intervention(s)) versus any comparison intervention (no intervention, a single intervention, or the same single or more intervention(s)). We also made four secondary comparisons: ii) OLs alone versus no intervention, iii) OLs alone versus a single intervention, iv) OLs, with a single or more intervention(s) versus the same single or more intervention(s), and v) OLs with a single or more intervention(s) versus no intervention.We included 24 studies, involving more than 337 hospitals, 350 primary care practices, 3005 healthcare professionals, and 29,167 patients (not all studies reported this information). A majority of studies were from North America, and all were conducted in high-income countries. Eighteen of these studies (21 comparisons, 71 compliance outcomes) contributed to the median adjusted risk difference (RD) for the main comparison. The median duration of follow-up was 12 months (range 2 to 30 months). The results suggested that the OL interventions probably improve healthcare professionals' compliance with evidence-based practice (10.8% absolute improvement in compliance, interquartile range (IQR): 3.5% to 14.6%; moderate-certainty evidence).Results for the secondary comparisons also suggested that OLs probably improve compliance with evidence-based practice (moderate-certainty evidence): i) OLs alone versus no intervention: RD (IQR): 9.15% (-0.3% to 15%); ii) OLs alone versus a single intervention: RD (range): 13.8% (12% to 15.5%); iii) OLs, with a single or more intervention(s) versus the same single or more intervention(s): RD (IQR): 7.1% (-1.4% to 19%); iv) OLs with a single or more intervention(s) versus no intervention: RD (IQR):10.25% (0.6% to 15.75%).It is uncertain if OLs alone, or in combination with other intervention(s), may lead to improved patient outcomes (3 studies; 5 dichotomous outcomes) since the certainty of evidence was very low. For two of the secondary comparisons, the IQR included the possibility of a small negative effect of the OL intervention. Possible explanations for the occasional negative effects are, for example, the possibility that the OLs may have prioritised some outcomes, at the expense of others, or that an unaccounted outcome difference at baseline, may have given a faulty impression of a negative effect of the intervention at follow-up. No study reported on costs or cost-effectiveness.We were unable to determine the comparative effectiveness of different approaches to identifying OLs, as most studies used the sociometric method. Nor could we determine which methods used by OLs to educate their peers were most effective, as the methods were poorly described in most studies. In addition, we could not determine whether OL teams were more effective than single OLs.Local opinion leaders alone, or in combination with other interventions, can be effective in promoting evidence-based practice, but the effectiveness varies both within and between studies.The effect on patient outcomes is uncertain. The costs and the cost-effectiveness of the intervention(s) is unknown. These results are based on heterogeneous studies differing in types of intervention, setting, and outcomes. In most studies, the role and actions of the OL were not clearly described, and we cannot, therefore, comment on strategies to enhance their effectiveness. It is also not clear whether the methods used to identify OLs are important for their effectiveness, or whether the effect differs if education is delivered by single OLs or by multidisciplinary OL teams. Further research may help us to understand how these factors affect the effectiveness of OLs.