In this paper, a part of ACKNOWLEDGMENTS was unintentionally omitted. The authors sincerely regret this error. The text should be as follows:
Corrected ACKNOWLEDGMENTS
This study was supported by the Foundation for Korean Urological Association in 2014 (FKUA-2014-001). This study used NHIS-NSC data (NHIS-2015-2-052) made by National Health Insurance Service (NHIS). The authors declare no conflict of interest with NHIS.