Comprehensive and long-term surveys of COVID-19 sequelae in Japan, an ambidirectional multicentre cohort study: study protocol
Authors: Nakagawara Kensuke , Namkoong Ho , Terai Hideki , Masaki Katsunori , Tanosaki Takae , Shimamoto Kyoko , Lee Ho , Tanaka Hiromu , Okamori Satoshi , Kabata Hiroki , Chubachi Shotaro , Ikemura Shinnosuke , Kamata Hirofumi , Yasuda Hiroyuki , Kawada Ichiro , Ishii Makoto , Ishibashi Yoshiki , Harada Sei , Fujita Takanori , Ito Daisuke , Bun Shogyoku , Tabuchi Hajime , Kanzaki Sho , Shimizu Eisuke , Fukuda Keitaro , Yamagami Jun , Kobayashi Keigo , Hirano Toshiyuki , Inoue Takashi , Kagyo Junko , Shiomi Tetsuya , Ohgino Keiko , Sayama Koichi , Otsuka Kengo , Miyao Naoki , Odani Toshio , Oyamada Yoshitaka , Masuzawa Keita , Nakayama Sohei , Suzuki Yusuke , Baba Rie , Nakachi Ichiro , Kuwahara Naota , Ishiguro Takashi , Mashimo Shuko , Minematsu Naoto , Ueda Soichiro , Manabe Tadashi , Funatsu Yohei , Koh Hidefumi , Yoshiyama Takashi , Saito Fumitake , Ishioka Kota , Takahashi Saeko , Nakamura Morio , Goto Ai , Harada Norihiro , Kusaka Yu , Nakano Yasushi , Nishio Kazumi , Tateno Hiroki , Edahiro Ryuya , Takeda Yoshito , Kumanogoh Atsushi , Kodama Nobuhiro , Okamoto Masaki , Umeda Akira , Hagimura Kazuto , Sato Toshiro , Miyazaki Naoki , Takemura Ryo , Sato Yasunori , Takebayashi Toru , Nakahara Jin , Mimura Masaru , Ogawa Kaoru , Shimmura Shigeto , Negishi Kazuno , Tsubota Kazuo , Amagai Masayuki , Goto Rei , Ibuka Yoko , Hasegawa Naoki , Kitagawa Yuko , Kanai Takanori , Fukunaga Koichi 
Published: November 2021

IntroductionThe rapid spread of COVID-19 posed a global burden. Substantial number of people died of the disease in the acute phase of infection. In addition, a significant proportion of patients have been reported to suffer from post-acute phase symptoms, sequelae of COVID-19, which may negatively influence the quality of daily living and/or socioeconomic circumstances of the patients. However, no previous study has comprehensively and objectively assessed the quality of life of patients by using existing international scales. Further, evidence of socioeconomic consequences among patients with COVID-19 is scarce. To address the multidimensional issues from sequelae of COVID-19, evidence from comprehensive surveys beyond clinical perspectives is critical that investigates health, and social determinants of disease progression as well as socioeconomic consequences at a large scale.Methods and analysisIn this study, we plan to conduct a nationwide and comprehensive survey for the sequelae of COVID-19 in a total of 1000 patients diagnosed at 27 hospitals throughout Japan. This study will evaluate not only the health-related status of patients from clinical perspectives but also the Health-related Quality of Life (HRQoL) scores, socioeconomic status and consequences to discuss the sequelae of the disease and the related risk factors. The primary endpoint is the frequency of long-term complications of COVID-19 infection. The secondary endpoints are risk factors for progression to sequelae of COVID-19 infection. The study will provide robust and important evidence as a resource to tackle the issues from the sequelae of COVID-19 from the multi-dimensional perspectives.Ethics and disseminationThis trial was approved by the Keio University School of Medicine Ethics Committee (20200243, UMIN000042299). The results of this study will be reported at a society meeting or published in a peer-reviewed journal.