Quality assessment of studies
S-N and A-M used the criteria provided by the Cochrane Collaborations
tool for assessment of quality and risk of bias in selected
studies[13]. Methodological features applied for assessment were:
(a) random sequence generation; (b) allocation concealment; (c) blinding
of participants and personnel; (d) blinding of outcome assessment; (e)
incomplete outcome data, (f) selective outcome reporting (reporting
bias), and (g) other potential sources of bias. According to the
recommendations of the Cochrane Handbook, studies were assessed to have
a high risk, low risk or unclear. Poorly reported articles were labeled
an item as “unclear”, suggesting an unclear or unknown risk of bias.