2.5. Risk of Bias/Quality Assessment
Thanks to the abundance of non-randomized studies showing in the
available literature, two independent reviewers (XXX and XXX) critically
appraised all the eligible studies with Methodological Index for
Nonrandomized Studies (MINORS) to assess the quality of included
studies. A senior reviewer made the final decision on the assessment if
a consensus was not achieved and supervised the entire process. The
MINORS instrument contains 12 items: 4 for comparative studies and 8 for
noncomparative studies. A score of 0 (not reported), 1 (reported but
inadequate), or 2 (reported and adequate) was given for each item,
resulting in an ideal maximum score of twenty-four for comparative
studies and sixteen for noncomparative studies. For non-randomized
studies, the methodologic quality was assessed as follows: 0 to 5, very
low quality of evidence; 6 to 10, low quality; 11 to 15, fair quality;
16, good quality. The outcomes of the risk-of-bias and quality
assessment provided the confidence level for the conclusions to be drawn
from this review.