Bruno R da Costa1, Pakeezah Saadat2, Reto Basciani3, Arnav Agarwal4, Bradley C Johnston5, Peter Jüni6. 1. Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada. Electronic address: bruno.dacosta@utoronto.ca. 2. Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada. Electronic address: pakeezah.saadat@mail.utoronto.ca. 3. Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Department of Anesthesiology, Cantonal Hospital Aarau, Aarau, Switzerland. Electronic address: reto.basciani@ksa.ch. 4. Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada. Electronic address: arnav.agarwal@mail.utoronto.ca. 5. Department of Community Health and Epidemiology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada; Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, ON, Canada; Department of Nutrition, Texas A&M University, College Station, TX, 77845, USA. Electronic address: bradley.johnston@tamu.edu. 6. Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada. Electronic address: peter.juni@utoronto.ca.
Abstract
OBJECTIVE: To compare assay sensitivity of the Visual Analogue Scale (VAS) for global osteoarthritis pain and the Western Ontario and McMaster University (WOMAC) pain subscale, and the associated between-trial heterogeneity in effect sizes (ES). DESIGN: We included trials with placebo, sham or non-intervention control that included at least 100 patients with hip or knee osteoarthritis per arm, reporting both VAS and WOMAC pain scores. ES were calculated as between-group difference in means divided by the pooled standard deviation and compared using a paired t-test. ES and τ2 as a measure of between-trial heterogeneity were combined using random-effects meta-regression with robust variance estimation to account for the correlation of data within trials and meta-analyses. RESULTS: Twenty-eight trials with 44 randomized comparisons were included. In 28 comparisons (64%), ES from VAS favoured the intervention more than those from WOMAC pain (P = 0.003). Twenty-six p-values (59%) were smaller according to VAS (P = 0.008). The 44 comparisons contributed to 12 meta-analyses. Eleven meta-analyses (92%) showed larger benefits of interventions according to VAS, with a combined overall difference in ES of -0.08 (95% CI -0.14 to -0.02). τ2 was similar for VAS and WOMAC pain (difference in τ2, -0.003, 95% CI -0.009 to 0.004). CONCLUSION: The VAS for global pain had slightly higher assay sensitivity at trial and meta-analysis levels than the WOMAC pain subscale without relevant increase in between-trial heterogeneity.
OBJECTIVE: To compare assay sensitivity of the Visual Analogue Scale (VAS) for global osteoarthritis pain and the Western Ontario and McMaster University (WOMAC) pain subscale, and the associated between-trial heterogeneity in effect sizes (ES). DESIGN: We included trials with placebo, sham or non-intervention control that included at least 100 patients with hip or knee osteoarthritis per arm, reporting both VAS and WOMAC pain scores. ES were calculated as between-group difference in means divided by the pooled standard deviation and compared using a paired t-test. ES and τ2 as a measure of between-trial heterogeneity were combined using random-effects meta-regression with robust variance estimation to account for the correlation of data within trials and meta-analyses. RESULTS: Twenty-eight trials with 44 randomized comparisons were included. In 28 comparisons (64%), ES from VAS favoured the intervention more than those from WOMAC pain (P = 0.003). Twenty-six p-values (59%) were smaller according to VAS (P = 0.008). The 44 comparisons contributed to 12 meta-analyses. Eleven meta-analyses (92%) showed larger benefits of interventions according to VAS, with a combined overall difference in ES of -0.08 (95% CI -0.14 to -0.02). τ2 was similar for VAS and WOMAC pain (difference in τ2, -0.003, 95% CI -0.009 to 0.004). CONCLUSION: The VAS for global pain had slightly higher assay sensitivity at trial and meta-analysis levels than the WOMAC pain subscale without relevant increase in between-trial heterogeneity.