Pioglitazone and bladder cancer

The study recruited 193 099 patients with diabetes aged >40 years from electronic health records of the Kaiser Permanente Northern California (KPNC) diabetes registry. Data on the use of pioglitazone and other antidiabetic medications were collected from prescription records. The KPNC cancer registry was used to identify site-specific cancer diagnoses. A further nested case–control study was conducted in 464 patients and 464 age-matched controls to assess for confounding factors such as race, smoking and occupational history.