Table 3

Risk of bias assessment for RCTs and pre–post studies

SourceRisk of bias (high, low, unclear)
Randomisation sequence allocationConcealmentPerformance biasAscertainment biasIncomplete outcome dataSelective reporting
 Campbell et al 33 LowLowUnclearUnclearLowUnclear
 Chen et al 39 UnclearUnclearLowLowLowUnclear
 Cheung et al 29 LowLowLowLowLowUnclear
 Gleeson et al 25 LowLowUnclearLowLowUnclear
 Hackney et al 32 HighHighHighUnclearLowUnclear
 Jeter et al 42 LowLowHighLowLowHigh
 Kovacs et al 30 LowLowUnclearLowLowUnclear
 Surakka et al 36 UnclearUnclearHighHighUnclearUnclear
 Waterman et al 34 LowLowHighLowLowLow
Pre–post with no comparison group
 Ackley-Holbrook et al 31 LowUnclear
 Jeter et al 41 HighUnclear
 Kingston37 UnclearUnclear
 Larsson43 LowUnclear
 Miszko et al 40 UnclearUnclear
 Ponchillia et al 27 LowUnclear
 Salari28 UnclearUnclear
 Surakka35 UnclearUnclear
  • *Not applicable.

  • RCT, randomised controlled trials.