Allocation Concealment and Intention-To-Treat Analysis Do Not Influence the Treatment Effects of Physical Therapy Interventions in Low Back Pain Trials: a Meta-epidemiologic Study.

Abstract

To evaluate if allocation concealment and intention-to-treat (ITT) analysis influence the treatment effects of physical therapy interventions in low back pain (LBP) trials. We searched on PubMed, Embase, Cochrane Database of Systematic Reviews, Physiotherapy Evidence Database (PEDro), and CINAHL up to February 2017. We included LBP trials that compared physical therapy interventions to placebo or no intervention or minimal intervention with pain or disability outcomes. Information about allocation concealment and ITT analysis was extracted from PEDro and pain and disability outcomes converted to a 0-100 scale. A meta-regression was performed to evaluate the influence of these methodological features of interest on treatment effects. Other covariates included in the meta-regression were sample size and sequence generation. We identified 128 eligible trials (pooled N=20,555 participants). A total of 44.5% of the trials achieved allocation concealment, while 32% performed ITT analysis. Meta regression analyses showed no influence of allocation concealment on treatment effects for pain (regression coefficient 0.009; 95% confidence interval [CI] -2.91 to 2.91) and disability (regression coefficient 1.13; 95% CI -1.35 to 3.62), and no influence of ITT analysis for pain (regression coefficient 1.38; 95% CI -1.73 to 4.50) or disability (regression coefficient 1.27; 95% CI -1.39 to 3.64). For the other covariates, there was also no clinically significant influence on the treatment effects. There is no influence of allocation concealment or ITT analysis on treatment effects of physical therapy interventions for pain and disability in LBP trials.