INS and type 2 diabetes mellitus: Hemmingsen Hemmingsen B B Christensen Christensen LL LL Wetterslev Wetterslev J J Vaag Vaag A A Gluud Gluud C C Lund Lund SS SS Almdal Almdal T T Comparison of metformin and insulin versus insulin alone for type 2 diabetes: systematic review of randomised clinical trials with meta-analyses and trial sequential analyses Comparison of metformin and insulin versus insulin alone for type 2 diabetes: systematic review of randomised clinical trials with meta-analyses and trial sequential analyses BMJ BMJ 2012 2012 344 344 e1771 e1771 10.1136/bmj.e1771 10.1136/bmj.e1771 supplied-pmid 22517929?