The aims were to explore the potential for detection bias by examining the association of antidiabetic medication with (1) PSA levels after initial prescription; (2) frequency of PSA testing and prostate biopsy; (3) the likelihood of having a biopsy if PSA was elevated; and (4) the likelihood of prostate cancer detection at biopsy in men exposed to antidiabetic medications compared with men not exposed. The gene discussed is KLK3; the disease is prostate cancer.