SPECIAL ARTICLE  COCHRANE REHABILITATION CORNER 5th COCHRANE REHABILITATION METHODOLOGICAL MEETING Open access

European Journal of Physical and Rehabilitation Medicine 2024 February;60(1):135-44

DOI: 10.23736/S1973-9087.23.08310-7

Copyright © 2023 THE AUTHORS

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language: English

The influence of bias in randomized controlled trials on rehabilitation intervention effect estimates: what we have learned from meta-epidemiological studies

Chiara ARIENTI ¹, Susan ARMIJO-OLIVO ^{2, 3}, Giorgio FERRIERO ^{4, 5}, Peter FEYS ⁶, Thomas HOOGEBOOM ⁷, Carlotte KIEKENS ⁸, Stefano G. LAZZARINI ¹, Silvia MINOZZI ^{9, 10}, Stefano NEGRINI ^{8, 11}, Aydan ORAL ¹², Elisa POLLINI ¹³ ✉, Livia PULJAK ¹⁴, Alex TODHUNTER-BROWN ¹⁵, Margaret WALSHE ¹⁶, Participants in the 5th Cochrane Rehabilitation Methodological Meeting 

¹ IRCCS Fondazione Don Gnocchi, Milan, Italy; ² Faculty of Economics and Social Sciences, University of Applied Sciences of Osnabrück, Osnabrück, Germany; ³ Faculties of Rehabilitation Medicine and Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada; ⁴ Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy; ⁵ Physical Rehabilitation Medicine Unit, Scientific Institute of Tradate IRCCS, Istituti Clinici Scientifici Maugeri, Tradate, Varese, Italy; ⁶ Uhasselt, Faculty of Rehabilitation Sciences, REVAL Rehabilitation Research Center, Hasselt, Belgium; ⁷ IQ Healthcare, Radboud University Medical Center, Nijmegen, the Netherlands; ⁸ IRCCS Istituto Ortopedico Galeazzi, Milan, Italy; ⁹ Department of Epidemiology, Lazio Regional Health Service, Rome, Italy; ¹⁰ Laboratory of Methodology of Systematic Reviews and Guidelines Production, Mario Negri Pharmacological Research Institute IRCCS, Milan, Italy; ¹¹ Department of Biomedical, Surgical and Dental Sciences, University "La Statale", Milan, Italy; ¹² Department of Physical Medicine and Rehabilitation, Istanbul Faculty of Medicine, University of Istanbul, Istanbul, Türkiye; ¹³ University of Brescia, Brescia, Italy; ¹⁴ Center for Evidence-Based Medicine and Healthcare, Catholic University of Croatia, Zagreb, Croatia; ¹⁵ Glasgow Caledonian University, Glasgow, UK; ¹⁶ Department of Clinical Speech and Language Studies, Trinity College, Dublin, Ireland

This 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.

KEY WORDS: Rehabilitation; Bias; Randomized controlled trials as topic