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BackgroundPrior studies have indicated that drugs against coronavirus disease 2019 (COVID-19) such as antiviral drugs, anti-inflammatory drugs, steroid and antibody cocktails are expected to prevent severe COVID-19outcomes and death.ObjectWe analyzed medical claim data in Japan to assess the effectiveness of drugs againstCOVID-19.MethodWe applied an average treatment effect model with inverse probability weighted regression adjustment, to the Medical Information Analysis Databank managed by National Hospital Organization in Japan. The outcome was death during hospitalization. Subjects were all inpatients, inpatients with oxygen therapy, and inpatients with respiratory ventilators, by three age classes: all ages, 65 years old or older, and younger than 65 years old. Data on physical characteristics, underlying diseases, administered drugs, the proportion of mutated strains, and vaccine coverage were used as explanatory variables for logistic regression.ResultEstimated results indicated that only an antibody cocktails (sotrovimab, casirivimab and imdevimab) raised the probability of saving life, even though these drugs were administered in few cases. On the other hand, other drugs might raise the probability of death.DiscussionResults indicated that only antibody cocktails was effective to save life using an average treatment effect model with inverse probability weighted regression adjustment. No other drugs such as remdesivir, dexamethasone, baricitinib and tocilizumab were found to be effective to save life, even in the pseudo-situation of random assignment.

Background: Earlier studies and clinical trials have shown that the drugs such as antiviral drugs, antibody cocktails, and steroids and anti-inflammatory drugs are expected to prevent severe coronavirus 2019 (COVID-19) outcomes and death. Methods: We used observational data for Japan to assess the effectiveness of these drugs for COVID-19. We applied propensity scoring, which can treat the choice of administered drug as a random assignment to inpatients, to the Medical Information Analysis Databank operated by National Hospital Organization in Japan. The outcome was defined as mortality. Subjects were all inpatients, inpatients with oxygen administration, and inpatients using respiratory ventilators, classified by three age classes: all ages, 65 years old or older, and younger than 65 years old. Information about demographical characteristics, underlying disease, administered drug, the proportion of Alpha, Beta and Omicron variant strains, and vaccine coverage were used as explanatory variable in logistic regression. Results: Estimated results indicated that only an antibody cocktail (sotrovimab, casirivimab and imdevimab) raised the probability to save life consistently. By contrast, other drugs might reduce the probability of saving life. The results indicated that an antiviral drug (remdesivir), a steroid (dexamethasone), and an anti-inflammatory drug (baricitinib and tocilizumab) might not contribute to saving life even at the pseudo-situation of random assignment. However, this logistic regression at the first step might have only insufficient explanatory power. Conclusions: We found a high likelihood that antibody cocktails were consistently effective to raise the probability of saving life, though a lesser likelihood in other drugs for older patients with mild to severe severity and all age patients with moderate severity.

Background Results of earlier studies have demonstrated underlying diseases such as cancer, diabetes mellitus, immunodeficiency, hypertension and heart failure to be risk factors for severe outcomes and mortality. Furthermore, clinical trials have shown that drugs such as antiviral drugs, antibody cocktails, steroids and anti-inflammatory drugs can be expected to prevent severe COVID-19 outcomes and death. Methods This study, using inpatient records from the Medical Information Analysis Databank covering national hospital organizations in Japan, was conducted to evaluate the effects of underlying diseases and/or administered drugs on mortality. Subjects were all inpatients receiving oxygen administration and inpatients using respiratory ventilators, categorized by three age classes: all ages, patients 65 years old or older, and patients younger than 65 years old. We used logistic regression to analyze outcomes for underlying diseases, administered drugs, age, sex, the proportion of the mutated strains, and vaccine coverage. Results Patients with hypertension, except for younger inpatients, have a lower risk of mortality (estimated coefficient 0.67 among all inpatients ( p < 0.01): 0.77 among inpatients with oxygen therapy ( p = 0.02) and 0.57 among inpatients with respiratory ventilation w ( p = 0.01)). Except for younger inpatients, antibody cocktail (casirivimab/imdevimab or sotrovimab) administration was associated with a higher probability of survival (estimated coefficient 0.27 among all inpatients ( p < 0.01)). It raised the survival probability consistently, although other drugs might have reduced the probability of survival. Conclusion These findings suggest that antiviral drugs (remdesivir, estimated coefficient 1.44 ( p < 0.01)), steroids (dexamethasone, estimated coefficient 1.85 ( p < 0.01)), and anti-inflammatory drugs (baricitinib, estimated coefficient 1.62 ( p < 0.01), and tocilizumab, estimated coefficient 2.73 ( p < 0.01)) might not contribute to survival. These results have not been reported from earlier studies. More sophisticated estimation procedures, such as treatment effect models, are necessary to obtain conclusive results.

Some mutated strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presumably have high infectivity and pathogenicity. Using Japanese medical claims data, we assessed the pathogenicity of Alpha and Delta variants and vaccine effectiveness by severity. Inpatient records from the Medical Information Analysis Databank for the National Hospital Organization were used. Severity was defined as the proportion of inpatients using respiratory ventilators among inpatients with oxygen administration. We regressed severity and fatality on the proportion of patients with Alpha or Delta variant and on vaccination coverage, while allowing for some lag to reflect development from infection to hospitalization. We also examined results obtained when using data for all new inpatients, instead of inpatients with oxygen administration, as the denominator for severity. Estimation results were better when using severity defined by inpatients with oxygen administration as the denominator than when using all new inpatients. Especially for severity measures for inpatients 65 years old or older with oxygen administration, we confirmed an association of vaccination with lower severity and an association of Delta variant infection with high severity. Vaccines were most effective for people 65 years old or older. The age distributions of inpatients and confirmed patients were greater than for people younger than 65 years old. Vaccination reduced severity and fatality and Alpha and Delta variants might increase severity and fatality among inpatients 65 years old or older receiving oxygen therapy.