The impact of the COVID-19 pandemic has been immense, while the epidemiology and pathophysiology remain unclear. Despite many casualties in many countries, there have been less than 1,000 deaths in Japan as of end of June, 2020. In this study, we analyzed the cases of COVID-19 patients admitted to our institution located in the Tokyo metropolitan area where the survival rate is higher than those in other cities in the world. Medical records of COVID-19 patients that were admitted to a single Japanese tertiary university hospital in the Tokyo metropolitan area between March 10th and June 2nd, 2020 were retrospectively reviewed. The identified COVID-19 cases were subdivided into two groups (severe and mild) depending on the need for mechanical ventilation. Those in the severe group required mechanical ventilation as opposed to those in the mild group. The data were analyzed using nonparametric tests expressed by median [interquartile range (IQR)]. A total of 45 COVID-19 patients were included, consisting of 22 severe cases (Group S) and 23 mild cases (Group M). Male sex (Group S, 95.5% vs. Group M, 56.5%, p<0.01), high body mass index (Group S, 24.89 [22.44–27.15] vs. Group M, 21.43 [19.05–23.75], p<0.01), and hyperlipidemia (Group S, 36.4% vs. Group M, 0%, p<0.01) were more seen in Group S. Five (22.7%) cases in Group S underwent extracorporeal membranous oxygenation (ECMO). On admission, lymphopenia, decreased albumin, and elevated fibrinogen, lactate dehydrogenase, transaminases, creatine kinase, C-reactive protein, and procalcitonin were observed in Group S. The median ICU and hospital stay were 13.5 [10.3–22.3] days and 23.0 [16.3–30.5] days, respectively, in Group S. As of June 28th, 2020, in Group S, 19 (86.4%) patients have survived, of which 17 (77.3%) were discharged, and 2 are still in treatments. Three died of multiple organ failure. All 23 patients in Group M have recovered. Male sex, high body mass index, and hyperlipidemia can be risk factors for severe COVID-19 pneumonia, and its overall short-term survival rate was between 77.3% and 86.4% in this study.

COVID-19 大流行的影响是巨大的，但流行病学和病理生理学仍不清楚。尽管许多国家出现了许多伤亡，但截至 2020 年 6 月底，日本的死亡人数还不到 1,000 人。在这项研究中，我们分析了我们位于东京都市区的机构收治的 COVID-19 患者的病例，这些患者的生存率比率高于世界其他城市。对 2020 年 3 月 10 日至 6 月 2 日期间入住东京都区一家日本三级大学医院的 COVID-19 患者的医疗记录进行了回顾性审查。根据机械通气的需要，已确定的 COVID-19 病例被分为两组（重度和轻度）。与轻度组相比，严重组的患者需要机械通气。使用以中位数[四分位数范围（IQR）]表示的非参数检验对数据进行分析。共纳入 45 例 COVID-19 患者，其中重症病例 22 例（S 组），轻症病例 23 例（M 组）。男性（S 组，95.5% vs. M 组，56.5%，p<0.01），高体重指数（S 组，24.89 [22.44–27.15] vs. M 组，21.43 [19.05–23.75]，p<0.01 ）和高脂血症（S组，36.4% vs. M组，0%，p<0.01）在S组中更为常见。S组中有5例（22.7%）接受了体外膜肺氧合（ECMO）。入院时，S 组观察到淋巴细胞减少、白蛋白减少以及纤维蛋白原、乳酸脱氢酶、转氨酶、肌酸激酶、C 反应蛋白和降钙素原升高。中位 ICU 和住院时间分别为 13.5 [10.3-22.3] 天和 23.0 [10.3-22.3] 天。 S组分别为16.3-30.5]天。截至2020年6月28日，S组中19例（86.4%）患者存活，其中17例（77.3%）出院，2例仍在治疗中。三人死于多器官衰竭。M组23名患者全部康复。男性、高体重指数和高脂血症可能是重症COVID-19肺炎的危险因素，本研究中其总体短期生存率在77.3%至86.4%之间。