Confusion of evidence‐based reviews and guidelines

© 2023 European Academy of Neurology
Hariz and colleagues [1] argue that the new EAN/MDS GL contradicts the repeated endorsements of pallidotomy by the MDS. The MDS has previously published “evidence based medicine (EBM) reviews,” which appraise each treatment on the basis of welldefined criteria but are not GLs. Clinical GLs, such as the new EAN/MDS GL, also take into consideration other variables, including context, summarizing the current medical knowledge, weighing the benefits and harms of treatments, and giving specific recommendations based on this information. The specific GRADE GL methodology allows for the evaluation of available scientific evidence with a sophisticated evaluation process that includes grading the strength of the evidence and the certainty of that evidence, out of which the recommendations are developed. These steps are well documented in our appendices 1 and 2 for methodology and appendices 3 and 4 for outcomes. Thus, the case of radiofrequency pallidotomy and deep brain stimulation (DBS) of the pallidum, which is discussed by Hariz et al, illustrates the difference between EBM reviews and GLs. The EBM review ranks pallidotomy at the same level as globus pallidus internus (GPi)-DBS: both treatments are considered “efficacious,” “clinically useful,” and coming with a “clinically acceptable risk with specialized monitoring,” but it does not express whether the treatments are equal in their application in patients overall. In our GL using the GRADE methodology, in contrast, GPi-DBS is recommended, whereas pallidotomy is recommended only with restrictions.