A brief introduction to the FUTang Updating medical REcords (FUTURE) database. Issue 3 (22nd September 2021) - Wang, Xinyu; Zeng, Yueping; Tian, Jian; Xu, Hui; Song, Fei; Guo, Yongli; Xu, Xin; Feng, Guoshuang; Ni, Xin