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.

OBJECTIVE: 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.

CONCLUSION: There is no influence of allocation concealment or ITT analysis on treatment effects of physical therapy interventions for pain and disability in LBP trials.