Mapping the methodological diversity of published drug discontinuation studies-a scoping review of study topics, objectives, and designs.

Background: Trials evaluating drug discontinuation (drug discontinuation trials, DDTs) show a broad methodological spectrum. There are several specific methodological aspects in drug discontinuation trials (e.g., determination of research question; configuration of intervention; definition of outcomes). To verify this specifies, we did a scoping review about the study designs of drug discontinuation trials.

Methods: A systematic literature search in Medline (PubMed), The Cochrane Library, EMBASE, CINAHL, Web of Science, and PsycINFO was performed. In a two-step selection process, we identified DDTs, which evaluate the discontinuation of one or more long-term medication as the investigated intervention, by two independent reviewers. Besides bibliographic data, we extracted several parameters to describe the used study design of the included DDTs: motivation for DDT, initially treatment aim of the discontinued medication, study design, methods of discontinuation, follow-up times, number of study participants, and outcome parameter.

Results: Out of 12,132 records, we included 581 DDTs. The most common motivation for doing a DDT were expected side effects (48.8%), the motivation of proving the efficacy of medication (21.6%), or doubts on the expected benefit of the used medication (13.8%). The majority of the discontinued medication was initially prescribed to improve the prognosis of a chronic disease (60.4%) or to relieve symptoms (31%). The study designs of the trials showed a broad methodological spectrum. The minority of the drug discontinuation trials were randomized controlled trials (34%).

Conclusion: The results of this scoping review illustrates the need for an evidence-based methodological standard for planning and conducting drug discontinuation trials.