PMC

Flowchart of study selection process.

Pooled estimate of relative risk and 95% CIs of colorectal cancer associated with metformin therapy based on four studies comprising 107,961 diabetic patients and 589 incident colorectal cancer cases. Squares indicate relative risk in each study. The square size is proportional to the weight of the corresponding study in the meta-analysis; the length of horizontal lines represents the 95% CI. The unshaded diamond indicates the pooled relative risk and 95% CI.

Pooled estimate of relative risk and 95% CIs of colorectal neoplasm associated with metformin therapy based on five studies comprising 108,161 patients with type 2 diabetes. Squares indicate relative risk in each study. The square size is proportional to the weight of the corresponding study in the meta-analysis; the length of horizontal lines represents the 95% CI. The unshaded diamond indicates the pooled relative risk and 95% CI.