Table 4.

Methodological quality of the nonrandomized controlled clinical trials.

Quality assessment for nonrandomized trials	Kohler et al. (7)
A clearly stated aim	2
Inclusion of consecutive patients	2
Prospective data collection	0
Endpoints appropriate to the aim of the study	2
Unbiased assessment of the study endpoint	0
A follow-up period appropriate to the aims of study	0
Less than 5% loss to follow-up	0
Prospective calculation of the sample size	0
An adequate control group	1
Contemporary groups	0
Baseline equivalence of groups	1
Adequate statistical analyses	2
Total score	10

The items are scored 0 (not reported), 1 (reported but inadequate) or 2 (reported and adequate). The global ideal score being 16 for non-comparative studies and 24 for comparative studies.