In the stratified Cox model, the metformin cohort had an aHR of 0.69 (95% CI = 0.49‐0.96, P = 0.0039) for prostate cancer, compared to the nonmetformin cohort after the adjustment of age, TCM for BPH use, TCM for DM use, insulin usage, and CCI (Table 2). This evidence concerns the gene INS and diabetes mellitus.