Table 1 Risk-of-bias assessment of the included studies according to the MINORS scale

A clearly stated aim

2

2

2

2

2

Inclusion of consecutive patients

2

2

2

2

2

Prospective collection of data

0

0

0

1

0

Endpoints appropriate to the aim of the study

2

2

2

2

2

Unbiased assessment of the study endpoint

1

1

1

1

1

Follow-up period appropriate to the aim of the study

2

2

1

2

2

Loss to follow-up less than 5%

2

2

2

2

2

Prospective calculation of the study size

0

1

0

0

0

An adequate control group

1

1

1

1

1

Contemporary groups

2

2

2

2

2

Baseline equivalence of groups

1

2

2

2

1

Adequate statistical analyses

1

2

1

2

1

Total score

16

19

16

17

16