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5 Outcome reporting bias in the non-pharmacological literature – diminishing research gaps and improving emerging health literature
  1. Gabriel Costa1,2,
  2. Lucas Helal2,3,4,5
  1. 1Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
  2. 2The BRIGHTER Meta-Research Group, Santa Catarina, Brazil
  3. 3Universidade do Extremo Sul Catarinense, Santa Catarina, Brazil
  4. 4Universidade Federal do Rio Grande do Sul, Rio Grande do Sul, Brazil
  5. 5Ottawa Hospital Research Institute, Ottawa, Canada


Outcome reporting bias in clinical trials contribute to research waste and threaten the credibility of published research, affecting clinical decisions. This is well documented in the literature, even in highly influential medical journals, being mostly focused in pharmacological trials. It is known that this type of bias can occur for a myriad of reasons, and one is the search for statistical significance for reported outcomes (especially the primary outcome). Another one can be lack of training in correct outcome reporting and trial registration, which can be more frequent in some research contexts. In this sense, outcome reporting bias seems anecdotally even more frequent in less established research areas that are not so familiar with reporting standards and methods of evidence-based medicine (EBM), as for example, in the non-pharmacological literature. Preliminary evidence studying non-pharmacological research areas in isolation from each other shows that outcome reporting bias is more frequent in non-pharmacological trials (NPT) than in drug trials (for example, doi: 10.1001/jamanetworkopen.2019.15360), possibly because of the role of regulatory agencies to correct problems in industry-funded trials. In this sense, highlighting and mapping these problems in non-pharmacological research can encourage researchers and professionals from emergent areas of medical knowledge to operate with higher standards of evidence, while at the same time helping to spread the principles of EBM to new researchers at strategic sites, providing tools to give formal training to professionals involved in this broad area of research, which encompasses different areas like nutrition, physiotherapy, physical activity and even psychology, many of them operating only more recently together with the principles of EBM. Lifestyle interventions such as nutrition and physical education are growing endeavors with high relevance for public health given the current epidemiological scenario, characterized by high prevalence of non-communicable diseases with lifestyle roots. These research areas are growing in low- and middle-income countries (LMICs) and have the potential to reduce the cost of chronic diseases for the health systems in these countries. Brazil, for example, has the largest public health system of the world, named Sistema Único de Saúde and offers in his primary, secondary and tertiary care non-pharmacological interventions. This said, highlighting and diminishing outcome reporting bias especially in the non-pharmacological literature would enhance overall research reporting and quality, improving emerging health literature that guide research areas that are emerging worldwide and that can reduce the overall cost of disease, this being especially important (but not only) in LMICs that can suffer from lack of proper investment in the public health system. In the light of this, it is also worth mentioning that me and my research collaborators and orienteers are currently leading an initiative to map these occurrences in the literature of NPT’s (as described in and with this we hope to make a positive contribution in the whole scenario outlined above.

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