Assessment of study quality
Validity was assessed using a modified version of the Joanna Briggs Institute Critical Appraisal of Evidence of Effectiveness tool for adequacy of randomisation, allocation concealment, withdrawals, blinding of outcome assessors, comparability of groups, comparability and reliability of outcomes and appropriateness of statistical analysis (maximum score of 10). Studies that scored 6 or above were deemed to be of appropriate methodological quality and were included in the analysis.