Table 1 Individual risk of bias assessment using the MINORS tool (Methodological index for non-randomized studies)

Adequate statistical analyses

Baseline equivalence of groups

Contemporary groups

An adequate control group

Prospective calculation of the study size

Loss to follow-up less than 5%

Follow-up period appropriate to the aim of the study

Unbiased assessment of the study endpoint

Endpoints appropriate to the aim of the study

Prospective collection of data

Inclusion of consecutive patients

A clearly stated aim

Total (%)