Title |
Control Group Design, Contamination and Drop-Out in Exercise Oncology Trials: A Systematic Review
|
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Published in |
PLOS ONE, March 2015
|
DOI | 10.1371/journal.pone.0120996 |
Pubmed ID | |
Authors |
Charlotte N. Steins Bisschop, Kerry S. Courneya, Miranda J. Velthuis, Evelyn M. Monninkhof, Lee W. Jones, Christine Friedenreich, Elsken van der Wall, Petra H. M. Peeters, Anne M. May |
Abstract |
Important considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates. Randomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the drop-out rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received. 40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7±9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0±12.8%) were even lower. Control groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials. |
X Demographics
Geographical breakdown
Country | Count | As % |
---|---|---|
United Kingdom | 5 | 24% |
United States | 2 | 10% |
Australia | 2 | 10% |
Canada | 1 | 5% |
Chile | 1 | 5% |
Unknown | 10 | 48% |
Demographic breakdown
Type | Count | As % |
---|---|---|
Members of the public | 11 | 52% |
Scientists | 6 | 29% |
Practitioners (doctors, other healthcare professionals) | 3 | 14% |
Science communicators (journalists, bloggers, editors) | 1 | 5% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
---|---|---|
Denmark | 1 | <1% |
Canada | 1 | <1% |
Unknown | 139 | 99% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Student > Ph. D. Student | 25 | 18% |
Student > Master | 24 | 17% |
Researcher | 14 | 10% |
Student > Bachelor | 14 | 10% |
Other | 10 | 7% |
Other | 24 | 17% |
Unknown | 30 | 21% |
Readers by discipline | Count | As % |
---|---|---|
Medicine and Dentistry | 24 | 17% |
Nursing and Health Professions | 21 | 15% |
Sports and Recreations | 17 | 12% |
Psychology | 7 | 5% |
Social Sciences | 7 | 5% |
Other | 27 | 19% |
Unknown | 38 | 27% |