Clinical practice is not always evidence-based and, therefore, may not optimise patient outcomes. Opinion leaders disseminating and implementing 'best evidence' is one method that holds promise as a strategy to bridge evidence-practice gaps. Opinion leaders are people who are seen as likeable, trustworthy and influential. Because of their influence, it is thought that they may be able to help and persuade healthcare providers to use evidence when treating and managing patients.
We searched the scientific literature for randomised controlled trials that evaluated the effectiveness of the use of opinion leaders to disseminate and implement evidence-based medicine. We found 18 trials involving more than 296 hospitals and 318 primary care practices. Most of the included studies had some methodological shortcomings. The effects of interventions varied across the 63 outcomes from 15% decrease in compliance to 72% increase in compliance with desired practice. The median adjusted RD for the main comparisons were: i) Five trials that compared opinion leaders alone to no intervention, +0.09; ii) Two trials that compared opinion leaders alone to a single intervention, +0.14; iii) Four trials that compared opinion leaders with one or more additional intervention(s) to the one or more additional intervention(s), +0.10 and iv) Ten trials that compared opinion leaders as part of multiple interventions to no intervention, +0.10. Overall, the median adjusted RD across all studies was +0.12 representing 12% absolute increase in compliance in the intervention group.
In a majority of studies the sociometric method was used to identify opinion leaders, while two studies used the informant method, but due to the few studies using this method we could not conclude whether the method of identification had any impact on the effectiveness of interventions.
Three studies used multidisciplinary teams to promote evidence-based practice. The median adjusted RD for these trials was +0.18 representing a 18% absolute increase in compliance in the intervention group. However, two of the trials involved multiple interventions, and therefore the effectiveness of opinion leader teams could not be distinguished.
The results of this review show that opinion leaders may promote evidence-based practice. These results are based on heterogeneous studies using a variety of different interventions, performed in a variety of different settings, and aiming at changing a number of different outcomes. In most of the included studies the role of the opinion leader was not clearly described (educational methods used, degree or frequency of involvement of opinion leaders), and it is therefore not possible to say what is the best way to optimise the effectiveness of opinion leaders.