The effectiveness of antiviral treatment in severe COVID-19 patients in Wuhan: a retrospective cohort study

Background Since the outbreak of COVID-19, the application of appropriate treatment strategy for COVID-19 patients, notably for the severe patients, was a huge challenge in case management. Therefore, we aimed to evaluate the effectiveness of antiviral treatment in severe COVID-19 patients. Methods A retrospective cohort study was conducted from January 8, 2020 to March 9, 2020 in four designated hospitals of COVID-19 in Wuhan, China. 138 severe COVID-19patients with above 18 years were included in this study. 109 patients receiving the antiviral treatment were selected in antiviral group. The remaining 29 patients were in control group. The primary outcome of the study was in-hospital death and length of hospitalization. Secondary outcomes included ICU admission, length of stays in ICU, use of mechanical ventilation, length of mechanical ventilation, and the development of complications. Univariate analysis and Kaplan-Meier curves were used to examined the association between antiviral treatment and the clinical outcomes of the COVID-19 patients. Results 48 (44.0%) and 15 (51.7%) deaths were occurred in antiviral and control groups, respectively. Antiviral treatment was not associated with the rate of fatal outcome in COVID-19 patients (P > 0.05). Among the survival patients, the median length of hospitalization was 11.0 days (IQR: 6.5–18.0) and 16.0 days (IQR: 8.5–26.0) in antiviral and control groups, respectively. No signicant association was identied between the antiviral treatment and the length of hospitalization in survival patients (P > 0.05). Moreover, the antiviral treatment was not statistically associated with ICU admission, mechanical ventilation and length of mechanical ventilation (P > 0.05, respectively). However, the length of ICU stays in deaths was different both groups (P < 0.05). The median length of ICU stays in deaths was 7.0 days (IQR: 3.0-14.3) and 15.5 days (IQR: 8.3–21.8) in antiviral and control groups, respectively. The occurrence of majority of complications were similar both groups. Sepsis was single complication in which the occurrence rates were statistical different between the antiviral group and control group (40.4% vs 13.8%, P < 0.01). Conclusion No benet of antiviral treatment in severe COVID-19 patients was observed in our study. Clinical physicians should cautiously prescribe the antiviral drugs in severe COVID-19 patients.


Introduction
Pandemic of coronavirus disease 2019 (COVID-19) led to 4.7 million cases and 0.3 million deaths in ve months [1]. COVID-19 was caused by an emerging infectious pathogen that named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [2]. The treatment strategy of an emerging infectious disease was a huge challenge for clinical practitioners because of missing the keys knowledges about the diseases. Although most of COVID-19 patients presented only mild symptoms, such as fever, cough, expectoration, chest distress, etc [3]. However, a part of COVID-19 patients developed the severe complications, even death [4]. Therefore, it is critical to improve the case management of severe cases, in order to reduce the mortality of COVID-19. However, no speci c therapeutic agents for COVID-19 was provided. As SARS-CoV-2 belongs to the Coronavirus family, clinical physicians tended to use antiviral drugs (e.g., abidor, ribavirin, oseltamivir, etc.) in the COVID-19 treatment. Recently, two randomized clinical trials (RCT) showed that the use of lopinavir-ritonavir and chloroquine diphosphate could not improve the clinical course of COVID-19 patients [5,6]. Nevertheless, the effectiveness of antiviral treatment in severe patients of COVID-19 were still unclear. Therefore, we conducted a retrospective cohort study to evaluate the effectiveness of the antiviral treatment in severe patients of COVID-19.

Methods
Study setting with other organ dysfunction needing intensive care unit (ICU) admission. In our study, all the severe and critical patients were grouped and labeled severe patients.

Exposure
All the patients receiving any antiviral treatment, including ribavirin, oseltamivir, abidor, interferon, and Kaletra (i.e. lopinavir/ritonavir), were selected in antiviral group. The patients receiving the treatment other than antivirus were selected in control group. Among the 138 severe patients of COVID-19, 109 (79.0%) were classi ed in antiviral group and 29 (21.0%) in control group. The daily doses of ribavirin, oseltamivir, abidor, interferon, and Kaletra were 0.8 g, 150 mg, 400mg, 8 million IU, and 800 mg, respectively. The cumulative duration of antiviral treatment was de ned as the period between the rst prescription date and the end of the nal prescription.

Outcomes
The primary outcome was de ned as the in-hospital death and duration of hospitalization. The secondary outcomes included the ICU admission, length of stays in ICU, use of mechanical ventilation, length of mechanical ventilation, and the development of complications.
Sepsis and septic shock were diagnosed according to the 2016 Third International Consensus De nition for Sepsis and Septic Shock [10]. AKI was diagnosed according to the KDIGO clinical practice guidelines [11], and acute cardiac injury was diagnosed by increased serum cardiac biomarkers. DIC was de ned according to the guidelines of the Scienti c Subcommittee on Disseminated Intravascular Coagulation of the International Society on Thrombosis and Haemostasis [12].

Data collection and covariates
The demographic and clinical data of patients, and the prescription and dispensing of drugs were extracted from the electric medical records.
The covariates of analysis were de ned as following: patients' basic characteristics (e.g. age, sex, body mass index (BMI), and smoking), comorbidities, surgery history, clinical signs and symptoms (e.g. fever, cough, sputum production, chest distress, etc.), ventilation mode at admission, vital signs and laboratory ndings, and the treatments other than antivirus (e.g. antibiotics, glucocorticoids, vasoactive drugs, high-ow oxygen therapy, etc.).

Statistical Analysis
The descriptive data were expressed as mean ± standard deviation (SD) or median with interquartile range (IQR) or range for the continuous variables. The number and percentage were used for describing the categorical variables. The statistical comparison between antiviral and control groups used t test for normally distributed data, Mann-Whitney test for non-normally distributed or graded variables, and chi-square (χ 2 ) test or Fisher's exact test for discrete variables. Kaplan-Meier analysis was applied for survival time analysis during hospitalization. The log-rank test was used to compare the length of hospitalization in survival patients and deaths. The survival analysis was strati ed by the combined treatments in survival patients and deaths. All analyses were performed with the use of R software (version 3.6.3, R Foundation for Statistical Computing). Two-sided P values of less than 0.05 were considered to indicate statistical signi cance.

General characteristics
In total, 138 severe patients were enrolled in our study. 109 (79.0%) patients were in antiviral group, and 29 (21.0%) in control group. The mean age of the 138 patients was 65.4 years old (SD: ± 12.6), and 90 (65.2%) patients were men (Table 1). Only 8 (5.8%) cases were smokers. 86 (63.3%) cases had coexisting disorders, including hypertension, diabetes, coronary heart disease, and renal insu ciency, chronic lung disease, cerebrovascular diseases, and malignant tumor (Table 1). 40 (29.0%) with a single co-morbidity and 46 (33.3%) with two or more co-morbidities. The most common symptoms at illness onset were fever, cough or expectoration, chest distress or dyspnea, fatigue, and breathlessness or wheezing ( Table 1). The general characteristics were similar between the patients in antiviral group and that in control group. The vital signs and laboratory ndings were also compared between the antiviral group and control group (Additional le 1: Table S1). No statistical differences in vital signs and most of laboratory ndings were identi ed both groups.

Treatments
Among the 109 patients receiving the antiviral treatment, ve different antiviral drugs were used. Ribavirin (36.2%) and oseltamivir (32.6%) were the mostly used antiviral drugs, followed by abidor (16.7%), interferon (11.6%), and Kaletra (5.1%) ( Table 2). The duration of the antiviral treatment varied with the speci c antiviral drugs, ranging from 3 days for Kaletra to 9 days for interferon. Most of the patients (85, 78.0%) in antiviral group received a single antiviral drug, and 24 (22.0%) received a combined antiviral therapy.

Outcomes and complications
In total, 63 (45.7%) patients died during hospitalization and 75 (54.3%) were discharged. The case-fatality rates were similar between the antiviral group and control group (44.0% vs 51.7%, P>0.05, Table 4). Moreover, the length of hospitalization of severe patients in antiviral group (median: 11.0, IQR: 6.5-18.0) was similar compared with that in control group (median: 16, IQR: 8.5-26.0, P>0.05, Table 4 and Fig. 1A). For the deaths, the in-hospital survival time did not signi cantly differ between these two groups ( Fig. 1B). For the survival patients, the length of hospitalization also had not statistical difference between these two groups ( Fig. 1C). In addition, the survival analyses strati ed by the combined treatments showed no signi cant difference on survival time or hospitalization length between the antiviral group and control group (Additional le 1: Fig. S1-S3).

Discussion
The results of this study suggested that the antiviral treatment was not associated with clinical improvement or reduction of mortality in severe patients of COVID-19. Although antiviral therapy seemed to reduce the length of stay in ICU for the patients of COVID-19, this length was only shortened in the deaths with antiviral treatment. In addition, antiviral treatment might increase the risk of developing sepsis in severe patients.
The effectiveness of antiviral treatment for COVID-19 is still controversial. Many researchers consider that ribavirin, remdesivir, lopinavir, emetine, and homoharringtonine have shown e cacy to inhibit SARS-CoV-2 or other coronavirus replication in vitro and combinational therapy may help to reduce the effective concentration of SARS-CoV-2 [13][14][15][16]. The molecular docking study has shown that the effectiveness of ribavirin, remdesivir, sofosbuvir, galidesivir and tenofovir as potent drugs for treating SARS-CoV-2 infection [17]. Another study proposed a combination of lopinavir, oseltamivir and ritonavir for controlling the virulence to a great extent in COVID-19 patients within 48 hours, and the combination of these three drugs had a better binding energy than single use [18]. Results of molecular modelling tools suggested that ribavirin, telbivudine, vitamin B12 and nicotinamide can be combined and used for COVID-19 treatment [19]. Atazanavir, remdesivir, efavirenz, ritonavir, dolutegravir, lopinavir, darunavir and Kaletra showed an inhibitory effect against the SARS-CoV-2 in the drugtarget interaction deep learning models, which may be used for the treatment of SARS-CoV-2 infection [20]. Interferon, as broad-spectrum antiviral biologicals, may account for a safe and easy to upscale treatment against COVID-19 in the early stages of infection [21,22], because exogenous infection may stimulate antiviral immunity against SARS-CoV-2 [23]. And both therapeutic regimens of interferon-α + lopinavir/ritonavir and interferon-α + lopinavir/ritonavir + ribavirin might be bene cial for treatment of COVID-19 in case series analysis [24]. One case report showed that late initiation of remdesivir might be effective in treating SARS-CoV-2 infection [25]. Another case report publication suggested that antiviral treatment including lopinavir/ritonavir, arbidol, and Shufeng Jiedu Capsule (i.e. a traditional Chinese medicine) could improve clinical symptoms in severe COVID-19 patients [26]. One case series in Chongqing of China demonstrated Kaletra and traditional Chinese medicine played an important role in the treatment of the viral pneumonia [27]. As such, many clinical physicians suggest that antiviral therapy is vital to reduce mortality in severe patients of COVID-19 [28]. However, our study observed no bene cial effects of antiviral drugs in severe COVID-19 patients.
However, the clinical effects of antiviral treatment are debatable to date. One study showed that oseltamivir has even no documented in vitro activity against SARSCoV-2 [29] and no bene t of oseltamivir treatment was observed in a single-center case series [30]. Although several publications have demonstrated with the potential e cacy to COVID-19 in humans, mostly through vitro experiments, pharmacological studies, case reports or case series analysis with small sample sizes. Therefore, RCT must be undertaken to further evaluate the e cacy of antiviral treatment. Recently, the World Health Organization (WHO) launched a multinational randomized trial, which study the effect of drugs that have been identi ed as promising based on in-vitro data and the early clinical experience with COVID-19, including remdesivir, lopinavir + ritonavir, lopinavir + ritonavir + interferon, and chloroquine/hydroxychloroquine [31]. One review also found 24 clinical trials that have already started with the repositioning of more than 20 medicines for COVID-19 treatment, such as human immunoglobulin, interferons, chloroquine, hydroxychloroquine, arbidol, remdesivir, favipiravir, lopinavir, ritonavir, oseltamivir, methylprednisolone, bevacizumab, and traditional Chinese medicines [32]. In addition, a recent RCT has showed that antiviral drug (lopinavir-ritonavir) did not accelerate clinical improvement, reduce mortality, or diminish throat viral RNA detectability in patients with severe COVID-19 cases [5]. The higher chloroquine diphosphate dosage should not be recommended for critically COVID-19 patients in another RCT [6]. Similar ndings have been identi ed in our cohort study. Our study showed that the risk of mortality, clinical course of severe COVID-19 patients did not improve with the use of antiviral drugs.
Sepsis was one of the common complications of COVID-19. The incidence of sepsis was higher in the antiviral group in our study. Although the bacterial infections are usually regarded as a leading cause of sepsis, one study suggested that viral infection may also cause sepsis syndrome [3]. In severe COVID-19 patients, alveolar macrophages or epithelial cells could produce various proin ammatory cytokines and chemokines in response to the infection of SARS-CoV-2. Virus infection might lead to more macrophage in ltration and the immune pathogenesis caused by the systemic cytokine storm [33]. And the microcirculation dysfunctions lead to viral sepsis. But further research is necessary to investigate the pathogenesis of sepsis in COVID-19. In our study, we found that more than 40% of patients had leucocytes over 9.5 × 10 9 per L, neutrophils over 6.3 × 10 9 per L or procalcitonin over 0.5 ng/mL in all patients on admission. These ndings revealed the bacterial infection in COVID-19 patients, but it is not persuasive to explain the high incidence of sepsis in COVID-19 patients receiving antiviral treatment. It may be due to disturbances of balance between virus-bacteria interactions by antiviral treatment [34], and virus clearance indirectly assist bacterial infection to induce a cytokine storm syndrome.
Our retrospective cohort study has some limitations. Firstly, the reliance on antiviral drugs use history to determine antiviral treatment exposures, while the assignment of the antiviral treatment was subject to the situation and environment of the hospital. The full extent of exposures may not have been captured. Secondly, our study only included the severe patients of COVID-19. The effectiveness of antiviral treatment in mild patients of COVID-19 cannot be analyzed in our study. Thirdly, the multivariate analysis was not carried out. The baseline characteristics of the severe COVID-19 patients were similar between antiviral group and control group. The confounding effect of other treatments was controlled by strati ed analysis. Therefore, our analysis accounted for these potential differences by univariate analysis and Kaplan-Meier curves and also by conducting subgroup analysis comparing clinical outcomes time between the two groups. Finally, our ndings were based on a retrospective cohort study. The RCT of antiviral drugs with multiple study sites should be planned to better evaluating the effectiveness of antiviral drugs.

Conclusions
In conclusion, no clinical bene t was observed in the severe patients of COVID-19 receiving ribavirin, oseltamivir, abidor, interferon, or Kaletra as treatment. The clinical practitioners should prescribe the antiviral drugs to the severe COVID-19 patients according to their clinical presentations. The antiviral treatment is not recommended to be a regular treatment for COVID-19.          Length of ICU stay by antiviral treatment in total patients (A), deaths (B) and survival patients (C). ICU, intensive care unit.