What is the influence of randomisation sequence generation and allocation concealment on treatment effects of physical therapy trials? A meta-epidemiological study.
OBJECTIVE
To determine if adequacy of randomisation and allocation concealment is associated with changes in effect sizes (ES) when comparing physical therapy (PT) trials with and without these methodological characteristics.


METHODS
Meta-epidemiological study.


METHODS
A random sample of randomised controlled trials (RCTs) included in meta-analyses in the PT discipline were identified.


METHODS
Data extraction including assessments of random sequence generation and allocation concealment was conducted independently by two reviewers. To determine the association between sequence generation, and allocation concealment and ES, a two-level analysis was conducted using a meta-meta-analytic approach.


METHODS
association between random sequence generation and allocation concealment and ES in PT trials.


RESULTS
393 trials included in 43 meta-analyses, analysing 44,622 patients contributed to this study. Adequate random sequence generation and appropriate allocation concealment were accomplished in only 39.7% and 11.5% of PT trials, respectively. Although trials with inappropriate allocation concealment tended to have an overestimate treatment effect when compared with trials with adequate concealment of allocation, the difference was non-statistically significant (ES=0.12; 95% CI -0.06 to 0.30). When pooling our results with those of Nuesch et al, we obtained a pooled statistically significant value (ES=0.14; 95% CI 0.02 to 0.26). There was no difference in ES in trials with appropriate or inappropriate random sequence generation (ES=0.02; 95% CI -0.12 to 0.15).


CONCLUSIONS
Our results suggest that when evaluating risk of bias of primary RCTs in PT area, systematic reviewers and clinicians implementing research into practice should pay attention to these biases since they could exaggerate treatment effects. Systematic reviewers should perform sensitivity analysis including trials with low risk of bias in these domains as primary analysis and/or in combination with less restrictive analyses. Authors and editors should make sure that allocation concealment and random sequence generation are properly reported in trial reports.
CLEAR Outcomes (Connecting Leadership, Education and Research) Research Program, University of Alberta, Edmonton Clinic Health Academy (ECHA), Edmonton, Alberta, Canada Faculty of Rehabilitation Medicine, Department of Physical Therapy, University of Alberta, Edmonton, Alberta, Canada Faculty of Rehabilitation Medicine, Rehabilitation Research Center, University of Alberta, Edmonton, Alberta, Canada.
Susan
S
Armijo-Olivo
Orthodontic Graduate Clinic, School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
Humam
H
Saltaji
Universitat Bern, Institute of Primary Health Care, Bern, Switzerland.
Bruno R
BR
da Costa
Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada Department of Physical Therapy, Catholic University of Maule, Talca, Chile.
Jorge
J
Fuentes
Faculty of Rehabilitation Medicine, Rehabilitation Research Center, University of Alberta, Edmonton, Alberta, Canada.
Christine
C
Ha
Faculty of Nursing, CLEAR Outcomes (Connecting Leadership Education & Research) Research Program, University of Alberta, Edmonton Clinic Health Academy|University of Alberta, Edmonton, Alberta, Canada.
Greta G
GG
Cummings
D015982:Bias; D016021:Epidemiologic Studies; D006801:Humans; D026741:Physical Therapy Modalities / Q000706:statistics & numerical data*; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment / Q000379:methods*
allocation concealment; meta-epidemiological; physical therapy; risk of bias; sequence generation