The PROSPERO platform opened the COVID-19 retrieval channel, carried out reasonable and meticulous classification management of the literature, and the retrieved literature met the inclusion standards. By August 3, 2020, 122 of the 189 SRs included should have reached the expected completion time, but in fact, only 11 SRs were completed, with the completion rate of only 9.02%. It can be explained that the reasons for the low completion rate may be that the data resources obtained in the early stage are insufficient, the data acquisition method is difficult, the expected completion time is too short, and the difficulty of the research is estimated incorrectly. Therefore, in the future research, we should try our best to avoid it, and we should make a correct evaluation of the research, whether from the feasibility or the time. To achieve a reasonable planning progress, as far as possible in the scheduled time to complete.
Through the reports on the retrieval database, it is not difficult to see that among the 188 SRs, except for one which is a single database, the remaining 187 SRs are all joint retrieval of multiple databases to obtain the corresponding data. Among them, PubMed / MEDLINE combined with EMBASE (152, 80.85%) was used most. At the same time, 136 (72.34%) SRs retrieved only English databases, and the remaining 52 (27.66%) were combined with Chinese and English databases. In this view, most of the databases are limited to English, and their data are not representative enough to a certain extent. The above shows that in the use of databases, it is advisable to search multi language databases at the same time to make the data more representative.
164 (86.77%) SRs were completed by one country independently, and 25 (13.23%) SRs were completed by cooperation. 69 (36.51%) of the SRs were undertaken by China, 22 (11.64%) by UK and 19 (10.05%) by Brazil. A total of 39 countries have participated in the registered SRs and 27 (69.23%) countries have formed cooperative relations. UK has the largest cooperation intensity, followed by China, Canada, Egypt, and Italy. A total of 301 institutions contributed to the registered SRs and 232 (77.08%) had cooperative relations. Chengdu University of traditional Chinese medicine has undertaken 7 (3.7%) projects, Liaoning University of traditional Chinese medicine has undertaken 6 (3.17%) projects, and children's Hospital of Chongqing Medical University has undertaken 4 (2.12%) projects, all of which are located in China. In the future, researchers should strengthen more comprehensive research and carry out extensive cooperation between countries and institutions.
3 (1.59%) of the included SRs did not report intervention methods. According to the treatment methods of China's COVID-19 diagnosis and treatment plan (Six Edition), the interventions in the rest of the literatures (186, 98.41% ) were manually divided into the following categories: antiviral therapy (81, 42.86%), respiratory support (16, 8.47%), circulation support (11, 5.82%), plasma therapy for consistent patients (11, 5.82%), immunotherapy (9, 4.76%), TCM treatment (9, 4.76%), rehabilitation treatment (5, 2.65%), anti-inflammatory treatment (16, 8.47%) and other treatments (31, 16.40%). We focused on antiviral treatment (81, 42.86%), of which 11 SRs did not specify the specific drugs. The most common used drugs were chloroquine / hydroquinone (26, 13.76%), followed by remdesivir (12, 6.35%), lobinavir / ritonavir (11, 5.82%), favipiravir (5, 2.65%), ribavirin (5, 2.65%), interference (5, 2.65%), abiron (4, 2.12%), abidor (4, 2.12%). This shows that there are a lot of repeated studies and there may be a waste of scientific research resources. The description of intervention measures was not standard enough. The included literature did not describe the treatment method, dosage and time in detail. Therefore, in the future research, researchers should be more careful to check the registered projects to avoid repeated research. Interventions used should be described in more detail and in a more standardized way.
Among all the outcome indicators, the most important outcome indicators were mortality rate (92, 48.66%), then adverse events (28, 14.81%) and the time of becoming negative for the coronavirus (22, 11.64%); the most frequently used secondary outcome was length of hospital stay (48, 25.40%), and then adverse events (43, 22.75%), ICU length of stay (30, 15.87%) and mechanical cultivation (23, 12.17%). By comparing the two types of outcome indicators, the common items were length of hospital stay, adverse events, ICU length of stay, the time of becoming negative for the coronavirus, and monitoring of mechanical ventilation. However, there are some differences between the two. The main outcome indicators are monitoring clinical symptoms and signs, while the secondary outcome indicators tend to be prognostic indicators, laboratory test data (IL-6, C-reactive protein, ALT), and the adverse reactions mainly focus on adverse drug reactions. Therefore, we can see that the determination of outcome indicators should be complementary as far as possible, so as to obtain more detailed and perfect information of outcome indicators, and avoid excessive repetition.