Table 2 Quality assessment for non-randomized trials

A clearly stated aim

2

2

2

2

Inclusion of consecutive patients

2

1

1

2

Prospective data collection

2

2

2

2

Endpoints appropriate to the aim of the study

1

1

1

1

Unbiased assessment of the study endpoint

1

1

1

0

A follow-up period appropriate to the aims of study

2

2

2

2

Less than 5 % loss to follow-up

2

2

2

2

Prospective calculation of the sample size

0

0

0

0

An adequate control group

2

2

2

2

Contemporary groups

1

0

1

1

Baseline equivalence of groups

2

2

2

2

Adequate statistical analyses

2

2

2

1

Total score

19

17

18

17