Hansen, Julie B3; Juhl, Carsten Bogh9; Boutron, Isabelle4; Tugwell, Peter5; Ghogomu, Elizabeth A T6; Pardo Pardo, Jordi6; Rader, Tamara6; Wells, George A6; Mayhew, Alain7; Maxwell, Lara6; Lund, Hans9; Christensen, Robin9
1 Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, Det Sundhedsvidenskabelige Fakultet, SDU2 Department of Sports Science and Clinical Biomechanics, Det Sundhedsvidenskabelige Fakultet, SDU3 Musculoskeletal Statistics Unit, Department of Rheumatology, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Frederiksberg, Copenhagen, Denmark SEARCH Research Group, Research Unit of Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.4 Paris Descartes University5 Ottawa Hospital Research Institute, Joint Coordinating Editor CMSG, Ottawa, Canada.6 University of Ottowa7 Cochrane Bias Methods Group, Ottawa, Canada Ottawa Hospital Research Institute, Centre for Practice-Changing Research, Ottawa, Canada.8 unknown9 Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, Det Sundhedsvidenskabelige Fakultet, SDU
protocol for a meta-epidemiological study
INTRODUCTION: The validity of systematic reviews and meta-analysis depends on methodological quality and unbiased dissemination of trials. Our objective is to evaluate the association of estimates of treatment effects with different bias-related study characteristics in meta-analyses of interventions used for treating pain in osteoarthritis (OA). From the findings, we hope to consolidate guidance on interpreting OA trials in systematic reviews based on empirical evidence from Cochrane reviews. METHODS AND ANALYSIS: Only systematic reviews that compare experimental interventions with sham, placebo or no intervention control will be considered eligible. Bias will be assessed with the risk of bias tool, used according to the Cochrane Collaboration's recommendations. Furthermore, center status, trial size and funding will be assessed. The primary outcome (pain) will be abstracted from the first appearing forest plot for overall pain in the Cochrane review. Treatment effect sizes will be expressed as standardised mean differences (SMDs), where the difference in mean values available from the forest plots is divided by the pooled SD. To empirically assess the risk of bias in treatment benefits, we will perform stratified analyses of the trials from the included meta-analyses and assess the interaction between trial characteristics and treatment effect. A relevant study-level covariate is defined as one that decreases the between-study variance (τ(2), estimated as Tau-squared) as a consequence of inclusion in the mixed effects statistical model. ETHICS AND DISSEMINATION: Meta-analyses and randomised controlled trials provide the most reliable basis for treatment of patients with OA, but the actual impact of bias is unclear. This study will systematically examine the methodological quality in OA Cochrane reviews and explore the effect estimates behind possible bias. Since our study does not collect primary data, no formal ethical assessment and informed consent are required. TRIAL REGISTRATION NUMBER: PROSPERO (CRD42013006924).