Table 3

Quality assessment of included studies (internal validity, external validity, precision and overall quality)

First author (year)Internal validity
(Cochrane Collaboration’s tool for assessing risk of bias)
External validityPrecisionOverall quality
Selection biasPerformance biasDetection biasAttrition biasReporting biasOther
Random sequence generationAllocation concealmentBlinding of patients and staffBlinding of outcome measuresCompleteness of outcome dataSelective reporting
Gatz (2020)37LowLowHighHighLowHighLowLowLowPoor
Clifford (2019)17LowLowHighHighLowHighHighLowHighPoor
Holden (2020)22LowLowLowHighLowLowLowLowLowGood
Vuvan (2020)34LowLowHighLowLowLowLowLowLowGood
Dupuis (2018)31LowLowLowLowLowLowHighLowLowGood
Parle (2017)32LowLowHighLowLowLowHighLowHighPoor
Rio (2017)35LowLowHighHighHighLowHighHighHighPoor
Stasinopoulos (2017)33Low?HighLowLowLow?HighHighPoor
van Ark (2015)36LowLowHighHighHighLowHighHighHighPoor
Rio (2015)20LowLowHigh?LowLowHighHighHighPoor
  • ?: unclear risk of bias.