INS and prostate cancer: 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).