Conflict of interest

Yoko Yamana has served as an endowed chair of Abbvie GK, Activaid, Alfresa Pharma, JMDC, Gilead Sciences, Nippon Kayaku, Eli Lilly Japan, Mochida Pharmaceutical, Janssen Pharmaceutical, Pfizer, Takeda Pharmaceutical, Bristol-Myers Squibb, Google GK. Masa Maeda has served as an endowed chair of Abbvie GK, EA Pharma, Zeria Pharmaceutical, JIMRO, Kyorin Pharmaceutical, and Mochida Pharmaceutical. Yusuke Miyatani has served as a speaker of AbbVie; received research funding from Japan Foundation for Applied Enzymology; and as an endowed chair of AbbVie, JIMRO, Zeria Pharmaceutical, Kyorin Pharmaceutical, Mochida Pharmaceutical, Otsuka Holdings, and EA Pharma. Toshifumi Hibi has received lecture fees from, AbbVie, EA Pharma, Janssen, JIMRO, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, Pfizer, Sandoz, Takeda Pharmaceutical, Zeria, advisory/consultancy fees from AbbVie, Celltrion Healthcare, EA Pharma, Eli Lilly, Gilead Sciences, Janssen, Mitsubishi Tanabe Pharma, Nichi-Iko, Nippon Kayaku, Takeda Pharmaceutical, Zeria, and research grants from AbbVie, Activaid, Alfresa Pharma, Bristol-Myers Squibb, Ferring Pharmaceuticals, Eli Lilly, Gilead Sciences, JIMRO, JMDC Inc., Janssen, Kyorin Pharmaceutical, Miyarisan, Mochida Pharmaceutical, Nippon Kayaku, Pfizer. Taku Kobayashi has served as a speaker, a consultant or an advisory board member for AbbVie, Alfresa Pharma, Bristol Myers Squibb, Celltrion, Covidien, EA Pharma, Eiken chemical, Eli Lilly, Ferring Pharmaceuticals, Gilead Sciences, Janssen, JIMRO, Kissei, Kyorin Pharmaceutical, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Sekisui Medical, Takeda Pharmaceutical, Zeria Pharmaceutical, and received research funding from AbbVie, Alfresa Pharma, EA Pharma, Kyorin Pharmaceutical, Mochida Pharmaceutical, Nippon Kayaku, Otsuka Holdings, Pfizer, Prometheus, Sekisui Medical, Zeria Pharmaceutical.

Human/animal rights

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008(5).

Informed consent

Informed consent was obtained from all patients to be included in the study.