The Trials within Cohorts design faced methodological advantages and disadvantages in the exercise oncology setting
Gal, Roxanne; Monninkhof, Evelyn M; van Gils, Carla H; Groenwold, Rolf H H; van den Bongard, Desirée H J G; Peeters, Petra H M; Verkooijen, Helena M; May, Anne M
(2019) Journal of Clinical Epidemiology, volume 113, pp. 137 - 146
(Article)
Abstract
OBJECTIVE: The Trials within Cohorts (TwiCs) design is an alternative for pragmatic RCTs and might overcome disadvantages as difficult recruitment, drop-out after randomization to control and contamination. We investigated the applicability of the TwiCs design in an exercise-oncology study regarding the recruitment process, representativeness of the study sample, contamination, participation,
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and drop-out. METHODS: The UMBRELLA Fit TwiCs evaluates an exercise intervention in inactive breast cancer patients. Eligible patients participating in the prospective UMBRELLA breast cancer cohort were identified and randomized. Patients randomized to the intervention (n=130) were offered the intervention while controls (n=130) were not informed. RESULTS: Fifty-two percent (n=68) accepted the intervention. Since this rate was lower than expected, a larger sample size was required than initially estimated (n=166). However, recruitment of 260 patients was still completed by one researcher within 30 months. Unselective eligibility screening and randomization before invitation improved representativeness. Disadvantage of the design might be inclusion of ineligible patients when cohort information is limited. Furthermore, the design faced higher non-compliance in the intervention group, but prevention of contamination. CONCLUSIONS: The TwiCs design improved logistics in recruitment and prevented contamination, but non-compliance due to refusal of the intervention was higher compared to conventional pragmatic exercise-oncology RCTs which may dilute the estimated intervention effect.
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Keywords: Breast cancer, cmRCT, Cohort multiple randomized controlled trial, Physical activity, Trials within Cohorts, TwiCs, Epidemiology, Journal Article
ISSN: 0895-4356
Publisher: Elsevier USA
Note: Funding Information: Funding: This work was supported by a Veni grant from the Netherlands Organisation for Health Research and Development (ZonMw 016.156.050). In addition, funding was provided by the Department of Radiotherapy, Imaging Division of the UMCU, and the Department of Clinical Epidemiology, Julius Center for Health Sciences and Primary Care, UMCU. Funding: This work was supported by a Veni grant from the Netherlands Organisation for Health Research and Development (ZonMw 016.156.050). In addition, funding was provided by the Department of Radiotherapy, Imaging Division of the UMCU, and the Department of Clinical Epidemiology, Julius Center for Health Sciences and Primary Care, UMCU. Authors’ contributions: A.M.M. was responsible for the acquisition of funding for UMBRELLA Fit, and H.M.V. and C.H.v.G. for the UMBRELLA cohort. A.M.M. and E.M.M. designed the study and were responsible for the general supervision of the study. R.H.H.G., C.H.v.G., D.H.J.G.v.d.B., P.H.M.P., and H.M.V. were involved in designing the study. R.G. was responsible for the acquisition of data. R.G. drafted the article, and all authors critically revised the article. All authors read, provided feedback, and approve the final article. The authors thank the study team of the UMBRELLA cohort at the Department of Radiotherapy, Imaging Division and Julius Center for Health Sciences and Primary Care of the University Medical Center Utrecht (UMCU) for running the cohort and collecting the data. The authors also thank the Department of Rehabilitation, Physical Therapy Science and Sports, University Medical Center Utrecht (UMCU) for the collaboration and their assistance. Funding: This work was supported by a Veni grant from the Netherlands Organisation for Health Research and Development (ZonMw 016.156.050). In addition, funding was provided by the Department of Radiotherapy, Imaging Division of the UMCU, and the Department of Clinical Epidemiology, Julius Center for Health Sciences and Primary Care, UMCU. Authors’ contributions: A.M.M. was responsible for the acquisition of funding for UMBRELLA Fit, and H.M.V. and C.H.v.G. for the UMBRELLA cohort. A.M.M. and E.M.M. designed the study and were responsible for the general supervision of the study. R.H.H.G., C.H.v.G., D.H.J.G.v.d.B., P.H.M.P., and H.M.V. were involved in designing the study. R.G. was responsible for the acquisition of data. R.G. drafted the article, and all authors critically revised the article. All authors read, provided feedback, and approve the final article. Publisher Copyright: © 2019 The Authors
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