Assessing the effect of sample size, methodological quality and statistical rigour on outcomes of randomised controlled trials on mobilisation, manipulation and massage for low back pain of at least 6 weeks duration

Dries M. Hettinga, Deirdre A. Hurley, Anne Jackson, Stephen May, Chris Mercer and Lisa Roberts

The objective of this study was to assess the effect of sample size, methodological quality and statistical rigour on outcomes of randomised controlled trials (RCTs) on manual therapy for non-specific low back pain (LBP) of at least 6 weeks duration, and to report results from RCTs with adequate sample size, methodological quality and statistical rigour.  Ten RCTs were included in the review but only two qualified as higher quality RCTs. Results from smaller trials and lower quality RCTs showed more variation in differences between the intervention and control groups than larger or higher quality trials. Evidence from large, high-quality RCTs with adequate statistical analyses showed that, for improvement in pain and function, a mobilisation/manipulation package is an effective intervention whilst manipulation used in isolation showed no real benefits over sham manipulation or an alternative intervention. No higher quality evidence considering massage was identified.

Many RCTs in the area of manual therapy for LBP have shortcomings in sample size, methodological quality and/or statistical rigour, but there remains evidence from higher quality RCTs to support the use of a manual therapy package, compared with GP care, for non-specific LBP of at least 6 weeks duration.

Physiotherapy, 10 March 2008, online article ahead of press
 

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