Reply to Leah Bensimon, Samy Suissa, and Laurent Azoulay's Letter to the Editor re: Daniel E. Spratt, Chi Zhang, Zachary S. Zumsteg, Xin Pei, Zhigang Zhang, Michael J. Zelefsky. Metformin and Prostate Cancer: Reduced Development of Castration-resistant Disease and Prostate Cancer Mortality. Eur Urol 2013;63:709–16