“…We identified 2824 unique references, of which 36 articles were read in full text. Sixteen articles fulfilled the inclusion criteria, 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 of which one 25 was later excluded because of an unacceptable risk of bias. Of the 15 included articles, 14 were based on observational data, mainly retrospective cohort studies, and one 24 was a randomized controlled study.…”