Table 3

GRADE summary of findings table

Summary of resultsQuality of the evidence (GRADE)
Follow-upNumber of participants(trials)SMD
(95% CI)
Short term385 (6 trials)−0.28 (−0.49 to −0.08)Limitations*No inconsistencyNo indirectnessImprecision†Low
Medium term173 (3 trials)−0.59 (−1.03 to −0.15)Limitations*No inconsistencyNo indirectnessImprecision†Low
Long term345 (5 trials) 0.01 (−0.39 to 0.41)Limitations*Inconsistency‡No indirectnessImprecision†Very low
Sensitivity analysis
Short term215 (3 trials)−0.27 (−0.54 to −0.05)No limitationsNo inconsistencyNo indirectnessImprecision†Moderate
Medium term 40 (1 trials)−0.32 (−0.95 to 0.31)No limitationsInconsistency§No indirectnessImprecision†Low
Long term215 (3 trials)0.13 (−0.14 to 0.40)No limitationsNo inconsistencyNo indirectnessImprecision†Moderate
  • *Lack of blinding of participants and personnel, attrition bias, unable to adequately assess selection bias risk.

  • †<400 participants for each outcome.

  • ‡Large statistical heterogeneity; I2=70%.

  • §Only single trial available, <400 participants therefore downgraded for inconsistency and imprecision.

  • Short term, ≤3 months; medium term, >3 and <12 months; long term, ≥12 months.

  • High quality: further research is unlikely to change our confidence in the estimate of effect.

  • Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect.

  • Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect.

  • Very low quality: we are uncertain about the estimate.

  • GRADE, Grading of Recommendations Assessment, Development and Evaluation; SMD, standardised mean difference.