title: The use of metformin in patients with prostate cancer and the risk of death.
abstract: BACKGROUND
  Given the conflicting results from observational studies, we assessed whether the use of metformin after a prostate cancer diagnosis is associated with a decreased risk of cancer-specific and all-cause mortality.
  
  
  METHODS
  This study was conducted linking four databases from the United Kingdom. A cohort of men newly diagnosed with nonmetastatic prostate cancer with a history of treated type II diabetes, between April 1, 1998 and December 31, 2009, was followed until October 1, 2012. Nested case-control analyses were performed for cancer-specific mortality and all-cause mortality, in which exposure was defined as use of metformin during the time to risk-set. Conditional logistic regression was used to estimate adjusted rate ratios (RR) of each outcome with 95% confidence intervals (CI).
  
  
  RESULTS
  The cohort consisted of 935 men with prostate cancer and a history of type II diabetes. After a mean follow-up of 3.7 years, 258 deaths occurred, including 112 from prostate cancer. Overall, the post-diagnostic use of metformin was not associated with a decreased risk of cancer-specific mortality (RR, 1.09; 95% CI, 0.51-2.33). In a secondary analysis, a cumulative duration ≥938 days was associated with an increased risk (RR, 3.20; 95% CI, 1.00-10.24). The post-diagnostic use of metformin was not associated with all-cause mortality (RR, 0.79; 95% CI, 0.50-1.23).
  
  
  CONCLUSIONS
  The use of metformin after a prostate cancer diagnosis was not associated with an overall decreased risk of cancer-specific and all-cause mortality.
  
  
  CONCLUSIONS
  The results of this study do not support a role for metformin in the prevention of prostate cancer outcomes.
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Canada. Experimental Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Leah
authors.initials: L
authors.lastname: Bensimon
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Canada.
authors.forename: Hui
authors.initials: H
authors.lastname: Yin
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Canada. Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada.
authors.forename: Samy
authors.initials: S
authors.lastname: Suissa
authors.affiliation: Experimental Medicine, McGill University, Montreal, Quebec, Canada. Department of Oncology, McGill University, Montreal, Canada.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pollak
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Canada. Department of Oncology, McGill University, Montreal, Canada. laurent.azoulay@mcgill.ca.
authors.forename: Laurent
authors.initials: L
authors.lastname: Azoulay
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000150:complications* / Q000401:mortality*; D012307:Risk Factors
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin