Systematic review| Volume 100, ISSUE 7, P1359-1366, July 2019

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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

Published:January 30, 2019DOI:



      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.

      Data Sources

      We searched on PubMed, Embase, Cochrane Database of Systematic Reviews, Physiotherapy Evidence Database (PEDro), and CINAHL up to February 2017.

      Study Selection

      We included LBP trials that compared physical therapy interventions to placebo or no intervention or minimal intervention with pain or disability outcomes.

      Data Extraction

      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.

      Data Synthesis

      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.


      List of abbreviations:

      CI (confidence interval), ITT (intention-to-treat), LBP (low back pain), PEDro (Physiotherapy Evidence Database), RCT (randomized controlled trial)
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