title: Pioglitazone and bladder cancer: a propensity score matched cohort study.
abstract: OBJECTIVE
  To examine whether exposure to pioglitazone use is associated with increased incidence of bladder cancer in patients with type 2 diabetes mellitus.
  
  
  METHODS
  A cohort study was done in the General Practice Research Database (GPRD) between 2001 and 2010. Two hundred and seven thousand seven hundred and fourteen patients aged ≥40 years with type 2 diabetes were studied (23,548 exposed to pioglitazone and 184,166 exposed to other antidiabetic medications but not pioglitazone). The association between pioglitazone and risk of bladder cancer was assessed by a Cox regression model. A propensity score matched analysis was done in a group of patients without missing baseline characteristics data.
  
  
  RESULTS
  Sixty-six and 803 new cases of bladder cancer occurred in the pioglitazone and other group, respectively (rates of 80.2 (95% CI 60.8, 99.5) and 81.8 (95% CI 76.2, 87.5) per 100,000 person-years respectively). Pioglitazone did not increase the risk of bladder cancer significantly compared with the other antidiabetic drugs treatment group, (adjusted hazard ratio (HR), 1.16, 95% CI 0.83, 1.62). In a matched propensity score analysis in which both groups had similar baseline characteristics (17,249 patients in each group), the adjusted HR was 1.22 (95% CI 0.80, 1.84).
  
  
  CONCLUSIONS
  The results suggest that pioglitazone may not be significantly associated with an increased risk of bladder cancer in patients with type 2 diabetes.
authors.affiliation: Medicines Monitoring Unit, Division of Medicine and Therapeutics, Ninewells Hospital and Medical School, Dundee, Scotland, UK. li@memo.dundee.ac.uk
authors.forename: Li
authors.initials: L
authors.lastname: Wei
authors.forename: Thomas M
authors.initials: TM
authors.lastname: MacDonald
authors.forename: Isla S
authors.initials: IS
authors.lastname: Mackenzie
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D000077205:Pioglitazone; D016016:Proportional Hazards Models; D012306:Risk; D045162:Thiazolidinediones / Q000009:adverse effects*; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced*
chemical_list: D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D000077205:Pioglitazone