title: Impact of metformin on metastases in patients with breast cancer and type 2 diabetes.
abstract: To analyze the impact of glucose-lowering drugs on metastases in women living in Germany who have been diagnosed with breast cancer (BC) and type 2 diabetes mellitus (T2DM).
  
  
  
  Women initially diagnosed with BC (2004-2013) were identified in the IMS Disease Analyzer database. Patients with a documentation of metastases at index date or during the following six months were excluded. We selected T2DM women between 40 and 90years of age who received glucose-lowering therapy (metformin, sulfonylureas, incretins, insulins, other medications). The primary outcome was the diagnosis of metastases recorded in the database between the index date and the end of follow-up. A multivariate Cox regression model was used to predict BC metastases on the basis of patient characteristics and glucose-lowering medication.
  
  
  
  A total of 4,953 women with BC and diabetes were included in the study. The mean age was 71.4years and 4.7% of patients had private health insurance coverage. Mean HbA1C was 7.1% and mean BMI was 30.6kg/m(2). After 5years follow-up, 9.2% of patients with metformin and 12.3% of patients without exhibited metastases (log-rank p-value=0.011), whereas 6.2% of patients with incretins and 11.0% of patients without incretins exhibited metastases (both log-rank p-values <0.001). Metformin (HR=0.73, 95% CI: 0.58-0.92) and incretins (HR=0.62, 95% CI: 0.45-0.84) both significantly decreased the risk of metastases. None of the other variables were significantly associated with diagnosis of metastases.
  
  
  
  The use of metformin and incretins in women with T2DM and BC may reduce the risk of metastases.
authors.affiliation: Department of Biology, École Normale Supérieure de Lyon, Lyon, France. Electronic address: louis.jacob.contacts@gmail.com.
authors.forename: Louis
authors.initials: L
authors.lastname: Jacob
authors.affiliation: Department of Epidemiology, IMS HEALTH, Frankfurt, Germany. Electronic address: kkostev@de.imshealth.com.
authors.forename: Karel
authors.initials: K
authors.lastname: Kostev
authors.affiliation: Department of Biometrics and Epidemiology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany. Electronic address: wolfgang.rathmann@ddz.uni-duesseldorf.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rathmann
authors.affiliation: Department of Gynecology and Obstetrics, Philipps-Universität Marburg, Marburg, Germany. Electronic address: kalder@med.uni-marburg.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Kalder
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005260:Female; D005858:Germany; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000517:prevention & control*
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin
keywords: Breast cancer; Diabetes; Germany; Metastasis; Metformin