Table 4

Assessment of internal validity, external validity, precision and overall quality of each study (see table 1 for criteria for overall study quality assessment)

AuthorInternal validity
(Cochrane’s Collaboration 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
Berrazueta et al 13 ???LowLowHighHighLowHighPoor
Pons et al 32 Low?HighHighLowHighHighHighHighPoor
Steunebrink et al 35 LowLow??LowHighHighLowLowModerate
Giner-Pascual et al 33 LowLow??HighHighHighHighHighPoor
Paoloni et al 29 ?LowLowLowLowHighLowLowLowGood
Kane et al 30 ??High?LowHighHighLowHighPoor
Paoloni et al 28 ?LowLowLowLowLowLowLowLowGood
Ozden et al 34 ???LowLowHighLowLowLowGood
Paoloni et al Low?LowLowLowHighHighLowLowModerate
Paoloni et al 27 ?Low?LowLowHigh?LowLowGood
  •  ?, unclear risk of bias.