Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Mean difference in change in HbA1c of metformin added on to insulin versus placebo and insulin comparator (boxes) and pooled estimates (diamonds) calculated by the random-effects DerSimonian and Laird method, stratified by type of diabetes. Horizontal bars and diamond widths denote 95% CIs, and box sizes indicate relative weight in the analysis. (A high-quality color representation of this figure is available in the online issue.)
