CORONA Data Viewer FAQ
What data sources are used?
- Data regarding clinical trial registrations come from international trial registration websites, such as clinicaltrials.gov. Information from these websites are aggregated by COVID-NMA and the aggregated data are exported for use in the CORONA Project.
- COVID-NMA: Thu Van Nguyen, Gabriel Ferrand, Sarah Cohen-Boulakia, Ruben Martinez, Philipp Kapp, Emmanuel Coquery, … for the COVID-NMA consortium. (2020). RCT studies on preventive measures and treatments for COVID-19 [Data set]. Zenodo. http://doi.org/10.5281/zenodo.4266528
- Information about treatment guidelines, such as those issues by the National Institutes of Health, are found on the website of the institutions providing guidelines.
- Data from published papers comes directly from the publications, as extracted by the CORONA Project’s data coordinators. Data are extracted as provided by the studies’ authors. However, errors may occur. Please report any errors or concerns to firstname.lastname@example.org.
What is the Research Prioritization grade?
The Research Prioritization (RP) grade is based on evidence from published randomized controlled trials. An evidence synthesis is performed for each drug or combination of drugs. If drugs are used in both the inpatient and outpatient settings, separate evidence syntheses are performed for each clinical setting. Each drug-setting receives an overall RP grade consisting of 1) a treatment effect assessment (likely beneficial, benefit unknown, not likely beneficial) and 2) certainty of evidence assessment (high certainty, moderate/low certainty). These grades are presented as letter grades for simplified comparison. The purpose of the RP grade is to identify promising drugs that require further evaluation.
What does the Research Prioritization grade indicate?
The purpose of the Research Prioritization grade is to identify promising drugs that require further evaluation. “A” treatments are likely beneficial with high certainty. They are generally well-studied and have a known likelihood of benefit. These treatments rarely need further research. “B” treatments are likely beneficial with moderate to low certainty. They have indicators of benefit, but this determination may be based on insufficient data. These treatments are well-positioned for further research to better characterize efficacy and should generally be prioritized for additional clinical trials. “B/C” treatments may have a trend towards benefit, but the data synthesis indicates that the benefit is not yet clear. “C” treatments are not likely beneficial with moderate to low certainty. They do not appear beneficial based on the available data, but there may be insufficient data to make a robust determination. These treatments are generally not prioritized for further research. “D” treatments are not likely beneficial with high certainty, based on a substantial amount of previous research. In general, “D” treatments do not require further research.
|A||Likely beneficial with high certainty|
|B||Likely beneficial with moderate to low certainty|
|C||Not likely beneficial with moderate to low certainty|
|D||Not likely beneficial with high certainty|
What is the Treatment Efficacy grade?
The Treatment Efficacy (TE) grade is based on evidence from high-quality randomized controlled trials. By limiting data to well-run, peer-reviewed studies, this grade is intended to provide an assessment of the available evidence for use in a clinical setting. In contrast, the Research Prioritization grade includes pre-prints, small studies, etc. that may provide valuable signals about a treatment’s efficacy but are unlikely to be robust enough to guide treatment recommendations with high certainty. In addition to this algorithmic grade, information on international treatment guidelines, such as from the NIH and IDSA, are provided alongside for further context. Note that some treatments are recommended for particular subgroups, such as those on mechanical ventilation. If treatment guidelines recommend that a drug is best used in a particular setting, this will be noted in the CORONA viewer along with the treatment efficacy letter grade. The purpose of the TE grade is to serve as an indicator of whether sufficient data exist in support of using a treatment in clinical practice at this time for COVID-19.
How are the Research Prioritization and Treatment Efficacy grades formulated?
The grades are both based on two components, a likelihood of benefit assessment and a certainty of evidence assessment, as described below.
Likelihood of benefit assessment
The treatment effect portion of the overall grade is currently calculated using two methods:
- Fisher’s method p-value: Combining P-values of the primary endpoints of each study for a given treatment. (as described in https://training.cochrane.org/handbook/current/chapter-10) We analyze p-values across all studies using Fisher’s method, where Pi is the one-sided p-value for study i. The test statistic follows a chi-squared distribution, which can be used to calculate a p-value for the null hypothesis that there is no evidence of an effect in at least one study. A p-value of <0.05 indicates that there is evidence of an effect in at least one study. Note that if a study provides a one-sided p-value, it is assumed that the hypothesis is in favor of the treatment under investigation.
- Proportion of studies with beneficial effect direction: Summarizing the effect direction of the primary endpoints of each study. For example, if mortality is lower in the treatment group, the treatment is noted as having a “beneficial” effect for that given endpoint. (“Beneficial” is used only to indicate the direction of effect, not it’s magnitude or significance)
We are considering including other methods of synthesizing treatment effect, including a true meta-analysis or an analysis focusing on summarizing a select number of effect estimates. However, both methods would be best used if comparing identical endpoints across multiple studies – e.g. mortality. We are extracting multiple data points from all publications, so it is possible to explore the methods in the medium-term.
Certainty of evidence assessment
The certainty of evidence for a given treatment is currently determined by looking at three metrics:
- Precision: Sample size across all peer-reviewed trials listed in PubMed included in the evidence synthesis (≥500 total patients treated is required for a high certainty of evidence). When calculating total sample size, we consider only articles that were peer-reviewed (to minimize the impact of erroneous results from pre-prints) and listed in PubMed (to minimize the impact of results from unreputable journals). However, pre-prints and those not listed in Pubmed are still used for drug effect estimate analysis
- Directness of evidence: Number of trials included in the evidence synthesis compared to placebo or standard of care. ≥50% of trials included in the evidence synthesis must be compared to placebo or standard of care for a high certainty of evidence.
- Publication quality: Number of trials included in the evidence synthesis published in a journal that is indexed in PubMed. ≥75% of trials included in the evidence synthesis must be published in a journal that is indexed in PubMed for a high certainty of evidence.
The certainty of evidence for a given treatment is determined by incorporating each of the factors above. A “high” certainty of evidence assessment is for treatments that meet the threshold for all the factors above. A “moderate” certainty of evidence is reserved for treatments that meet some but not all the thresholds, and a “low” certainty of evidence is assigned to treatments that meet none.
What does a trial ID starting with XXX indicate?
Trials that have a trial ID beginning with XXX were not known to have a trial registration number. This may be because the published paper did not indicate a trial registration number and data coordinators could not link it to a known trial. It may also occur if a trial was run without being registered. Errors may occur during the data extraction process. Please report any errors or concerns to email@example.com.
How can the data be used?
Data may be used freely and no permission is required. However, we do request attribution when using the manually extracted data (including study endpoint values, p-values, effect estimates, etc.).
Who should I contact with questions or concerns?
The data in this project are extracted manually from published papers by data coordinators. Errors may occur. Please report any errors or concerns to firstname.lastname@example.org.