In December 2019, A group of unexplained pneumonia patients appeared in Wuhan, 27 Hubei Province, China. And then a novel coronavirus was isolated from patients' 28 airway epithelial cells which is the seventh member of the family of coronaviruses, 29 named 2019-nCoV. (1) The danger of 2019-nCoV is that it may resemble the Middle 17, 2020, the mortality rate was 67% and only 9.5% could be discharged. (4) 41 Similarly, a Chinese expert, academician Zhong, has shown that severe pneumonia is 42 independently associated with admission to intensive care units, mechanical 43 ventilation, or death (sub-distribution risk ratio, 9.80; The 95% confidence interval, The following all available information were extracted, including the first author, such as odds ratios. Heterogeneity among studies was calculated and assessed using 97 the Chi-square test and I 2 statistic. Different ranges of I 2 reflect the effects of 98 heterogeneity on the predictive value of meta-analyses. when I 2 ＜25% means low 99 heterogeneity; I 2 =25%-50% means moderate heterogeneity; I 2 ＞50% means high 100 heterogeneity.(9) When I 2 > 50%, we chose the random-effects model to analyze. In 101 order to assess the influence of every individual study to the pooled results, one study 102 was excluded in sequence to the sensitivity analysis and if there was statistical 103 heterogeneity, sensitivity analysis would determine the source of heterogeneity.(10) 104 We assessed publication bias using funnel plots, by Begg's adjusted rank correlation test.(11) Statistical tests were two-sided and used a significance level of p＜0.05.
Study Selection 108 We searched 2207 studies from the online database of WHO and 1 through manual 109 search. After removing duplicate, 2133 related articles were included for further Table 1 . 127 According to previous studies, (4, 5) the composite endpoint can indicate a poor 128 prognosis. We extracted and analyzed the endpoints of all enrolled patients as shown 129 in Figure 1 (A). The combined mortality was 0.06 (95% CI 0.03-0.11, P=0.00) and the 130 combined rate of the admission to the intensive care unit was 0.09 (95% CI 0.05-0.14, 131 P=0.00), the combined rate of mechanical ventilation treatment was 0.06 (95% CI Our study indicated that the overall poor prognosis rate of COVID 19 was about 189 7%, which is consistent with other relevant studies. The mortality rate was higher than reported, which may be explained by Berkson's bias that severe patients tend to get 191 priority hospitalization. The rate of treatment with mechanical ventilation was 6%, 192 which may be lower than that of some other studies, possibly due to incomplete data to the particularity of covid-19, the clinical data included in the articles were quite 229 different, resulting in great heterogeneity. Therefore, the random effect model was 230 adopted in this study, which poses a challenge to the partial results of this study and 231 requires further study in larger and higher-quality studies.
The overall Composite endpoint incidence of COVID 19 was about 7%, the mortality 234 rate was 6%, ICU admission rate was 9%, and mechanical ventilation rate was 6%, 