Adjusted fatality rates of COVID19 pandemic: a comparison across countries

  1. Carlos Canelo-Aybar
  2. Jessica Beltran
  3. Marilina Santero
  4. Pablo Alonso-Coello

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Abstract

Background: A key impact measure of COVID-19 pandemic is the case fatality rate (CFR), but estimating it during an epidemic is challenging as the true number of cases may remain elusive. Objective: To estimate the CFR applying a delay-adjusted method across countries, exploring differences to simple methods and potential correlation to country level variables. Methods: Secondary analysis of publicly available data from countries with ≥500 cases by April 30th. We calculated CFR adjusting for delay time from diagnosis to death and using simple methods for comparison. We performed a random effects meta-analysis to pooling CFRs for all countries and for those with high testing coverage and low positivity rate. We explored correlation of adjusted CFR with age structure and health care resources at country level. Results: We included 107 countries and the Diamond Princess cruise-ship. The overall delay adjusted CFR was 2.8% (95%CI: 2.1 to 3.1) while naive CFR was 5.1% (95%CI: 4.1 to 6.2). In countries with high testing coverage/low positivity rate the pooled adjusted CFR was 2.1% (95%CI: 1.5 to 3.0), there was a correlation with age over 65 years (β = 0.12; 95%CI: 0.06 to 0.18), but not with number of physician or critical care beds. Naive method underestimated the CFR of the CFR with a median of 1.3% across countries. Conclusion: Our best estimation of CFR across countries is 2% and varies according to the aged population size. Modelers and policy makers may consider these results to assess the impact of lockdowns or other mitigation policies.

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    SciScore for 10.1101/2020.05.13.20099796: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Some previous analysis has also attempted to estimate the CFR with different limitations that we have attempted to overcome. One study adjusted the delay time between diagnosis to death an reported CFR for 82 countries outside China of 4.24%, but this was calculated using a fairly simplistic method, based on the number of cases of 13 days previous to the assessment date [27]. Another study collected data from several surveillance sources of cases from mainland China only, adjusting for under-ascertainment, and time delay; the authors obtained a CFR of 1.38%, increasing to 6.4% in those older than 64 years [24]. The Centre of Evidence Based Medicine used a meta-analytic approach to calculate a prediction interval across countries of between 0.84% to 8.67%. The authors did not provide a pooled estimate due to the large heterogeneity observed. However, by using a fixed effect model the authors assumed the existence of an only true value, an assumption that is not appropriate to account for different true CFR across countries, they relied in naive estimates, and did not considering testing coverage in their assessment. Recently, two non-peer reviewed seroprevalence studies reported estimates for the infectious fatality rate. In the first one, researchers from the university of Bonn took serological samples from approximately 1,000 inhabitants of the German town of Gangelt (population of 12,529 people), estimating an infection rate of 14%, and a fatality rate of 0.37%. Another stu...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
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    • No protocol registration statement was detected.

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  2. Version published to 10.1101/2020.05.13.20099796v1 on medRxiv