ABSTRACT
Overall survival (OS) is considered the standard clinical endpoint to support effectiveness claims in new drug applications globally, particularly for lethal conditions such as cancer. However, the source and reliability of OS in the setting of clinical trials have seldom been doubted and discussed. This study first raised the common issue that data integrity and reliability are doubtful when we collect OS information or other time-to-event endpoints based solely on simple follow-up records by investigators without supporting material, especially since the 2019 COVID-19 pandemic. Then, two rounds of discussions with 30 Chinese experts were held and 12 potential source scenarios of three methods for obtaining the time of death of participants, including death certificate, death record and follow-up record, were sorted out and analysed. With a comprehensive assessment of the 12 scenarios by legitimacy, data reliability, data acquisition efficiency, difficulty of data acquisition, and coverage of participants, both short-term and long-term recommended sources, overall strategies and detailed measures for improving the integrity and reliability of death date are presented. In the short term, we suggest integrated sources such as public security systems made available to drug inspection centres appropriately as soon as possible to strengthen supervision. Death certificates provided by participants' family members and detailed standard follow-up records are recommended to investigators as the two channels of mutual compensation, and the acquisition of supporting materials is encouraged as long as it is not prohibited legally. Moreover, we expect that the sharing of electronic medical records and the legal disclosure of death records in established health registries can be realized with the joint efforts of the whole industry in the long-term. The above proposed solutions are mainly based on the context of China and can also provide reference for other countries in the world. © 2022 The Authors
ABSTRACT
Objective To explore the predictive value of low-dose biphasic (inspiratory and expiratory) CT air trapping sign and semi-quantitative score in predicting abnormal blood gas parameters and progression to severe disease in COVID-19 patients. Methods Patients with non-severe COVID-19 who were diagnosed by nucleic acid testing and hospitalized in designated hospitals in Wuxi City from January 23 to February 29, 2020 were prospectively and consecutively recruited. All patients received low-dose biphasic CT examination on admission and repeated CT examination at regular intervals during the course. On the inspiratory phase admission of the bipolar CT, the scope of the lesion was evaluated by semi-quantitative score, and the air trapping sign on bipolar CT was assessed. The differences of semi-quantitative score, the presence of the air trapping sign and other clinical factors were compared between the patients with abnormal and the normal blood gas index, as well as between the cases progressed to severe disease and cases without disease progression using the independent sample t-test or χ2test. The area under the curve (AUC) of receiver operating characteristic (ROC) and the comprehensive discriminant improvement index (IDI) were used to evaluate the predictive effectiveness of the semi-quantitative scores, air trapping sign, and combination of two factors in differentiating cases with abnormal and normal blood gas indexes, as well as in differentiating cases with and without disease progression to severe COVID-19 cases. Results In total 51 non-severe COVID-19 cases were included, with 16 cases showed air trapping sign during the first biphasic CT examination on admission. During the course of the disease, there were 13 patients with abnormal blood gas index, and 9 cases displaying air trapping sign (9/13). All 7 cases with progression to severe cases showed air trapping sign (7/7). Patients with advanced age, air trapping sign and higher semi-quantitative score were found more likely to have abnormal blood gas index (t=3.10, χ2=9.38, t=3.34, P<0.05);patients with advanced age, underlying diseases, air trapping sign and higher semi-quantitative score were more likely to develop into severe disease (t=2.68, χ2=6.65, χ2=4.25, t=4.33, P<0.05). The AUC of semi-quantitative score, air trapping sign and combination of two factors in distinguishing abnormal blood gas index from normal blood gas index was 0.803, 0.754 and 0.794 respectively. The AUC of semi-quantitative score, air trapping sign and combination of two factors in distinguishing cases with progression to severe cases from non-progression was 0.881, 0.898 and 0.932, respectively. Air trapping sign combined with semi-quantitative score significantly improved the prediction effectiveness of disease progression, compared with semi-quantitative score or air trapping sign (IDI=0.271, 0.117). Conclusion Air trapping sign and semi-quantitative score might be used as effective indicators to predict the progression of COVID-19 cases, and the combination of these two factors might be more helpful to predict the disease progression.
ABSTRACT
The COVID-19 caused by the novel coronavirus is still spreading globally, and blocking its airborne transmission route is of great significance to control the pandemic. The conventional plasma air disinfection devices show advantages in their dynamic and rapid capabilities, but the disinfection performance is limited by a single method, besides, there exists the risk of secondary infection during maintenance. In this work, according to the physiological characteristics of the novel coronavirus, an air disinfection device based on thermally coupled corona discharge was proposed for the improvement of conventional plasma air disinfection technology, which adopted the wire-plate array electrode structure to initiate corona discharge, and utilized heating wires embedded in the collection plate to achieve centralized heating. The discharge para-meters were measured, and a discharge power at stable operation was discovered to be as high as 5.6 W, for which the discharge law was found to obey the Townsend relationship. Measurement and simulation of the thermal parameters showed that, compared with the overall air heating, the efficiency of centralized heating was increased by 17 times, with minimal impact on the ambient temperature. Bacillus amyloliquefaciens and Bacillus subtilis bacteriophages were used as model bacteria and virus to verify the disinfection performance. Results demonstrate that the killing performance is effectively enhanced via thermally coupled corona discharge, with a removal rate of residual virus on the collection plate increasing by 99.97%, thereby reducing the risk of secondary infection. This work lays a device foundation for killing the airborne novel coronavirus, and also provides a technical reference for cutting its airborne transmission. © 2022, High Voltage Engineering Editorial Department of CEPRI. All right reserved.