Arienti, CArmijo-Olivo, SFerriero, GFeys, PHoogeboom, TKiekens, CLazzarini, SGMinozzi, SNegrini, SOral, APollini, EPuljak, LTodhunter-Brown, AWalshe, MBattel, ICeravolo, MGColvin, CCordani, CCôté, PCusick, ADan, BDe Groote, WDel Furia, MJEvery-Palmer, SGimigliano, FGutenb-Runner, CInnocenti, TJuhl, CBLevack, WMMLiguori, SMachalicek, WMartin, RMerlo, FMeyer-Feil, TMiranda, LMosconi, BRøe, CShearer, HWong, J2024-05-232024-05-232023-12-12European Journal of Physical and Rehabilitation Medicine, ISSN: 1973-9087 (Print); 1973-9095 (Online), Edizioni Minerva Medica, 60(1), 135-144. doi: 10.23736/S1973-9087.23.08310-71973-90871973-9095http://hdl.handle.net/10292/17594This study aimed to synthesize evidence from studies that addressed the influence of bias domains in randomized controlled trials on rehabilitation intervention effect estimates and discuss how these findings can maximize the trustworthiness of an RCT in rehabilitation. We screened studies about the influence of bias on rehabilitation intervention effect estimates published until June 2023. The characteristics and results of the included studies were categorized based on methodological characteristics and summarized narratively. We included seven studies with data on 227,806 RCT participants. Our findings showed that rehabilitation intervention effect estimates are likely exaggerated in trials with inadequate/unclear sequence generation and allocation concealment when using continuous outcomes. The influence of blinding was inconsistent and different from the rest of medical science, as meta-epidemiological studies showed overestimation, underestimation, or neutral associations for different types of blinding on rehabilitation treatment effect estimates. Still, it showed a more consistent pattern when looking at patient-reported outcomes. The impact of attrition bias and intention to treat has been analyzed only in two studies with inconsistent results. The risk of reporting bias seems to be associated with overestimation of treatment effects. Bias domains can influence rehabilitation treatment effects in different directions. The evidence is mixed and inconclusive due to the poor methodological quality of RCTs and the limited number and quality of studies looking at the influence of bias and treatment effects in rehabilitation. Further studies about the influence of bias in RCTs on rehabilitation intervention effect estimates are needed.Copyright © 2023 The Authors. This is an open access article distributed under the terms of the CC BY-NC-ND 4.0 license which allows users to copy and distribute the manuscript, as long as this is not done for commercial purposes and further does not permit distribution of the manuscript if it is changed or edited in any way, and as long as the user gives appropriate credits to the original author(s) and the source (with a link to the formal publication through the relevant DOI) and provides a link to the license.https://creativecommons.org/licenses/by-nc-nd/4.0/Participants in the 5th Cochrane Rehabilitation Methodological Meeting4202 Epidemiology42 Health SciencesRehabilitationBehavioral and Social ScienceClinical ResearchClinical Trials and Supportive Activities8 Health and social care services research8.4 Research design and methodologies (health services)1103 Clinical Sciences1106 Human Movement and Sports Sciences1117 Public Health and Health ServicesRehabilitation4201 Allied health and rehabilitation science4203 Health services and systemsHumansRandomized Controlled Trials as TopicBiasEpidemiologic StudiesHumansEpidemiologic StudiesRandomized Controlled Trials as TopicBiasHumansRandomized Controlled Trials as TopicBiasEpidemiologic StudiesJournal ArticleOpenAccess10.23736/S1973-9087.23.08310-7