Quality assessment
Since 6 out of 8 included studies were nonrandomized trials without control groups, the Methodological Index for Nonrandomized Studies (MINORS) tool was used to assess the article quality. The 8 methodological items in MINORS are as follows: include a clearly stated aim, inclusion of consecutive patients, prospective collection of data, endpoints appropriate to the aim of the study, unbiased assessment of the study endpoint, follow-up period appropriate to the aim of the study, loss to follow up less than 5% and prospective calculation of the study size. Every item can be scored as 0 (not reported), 1 (reported but inadequately), or 2 (reported adequately)28.
In addition, the quality of the 2 included randomized controlled trials (RCTs) was assessed using the Cochrane Risk of Bias Tool (RoB2), which evaluates the following aspects: randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome and selection of the reported results. Each domain of RoB2 is rated as “low risk of bias”, “some concerns”, or “high risk of bias”29.