Obesity, old age and frailty are the true risk factors for COVID-19 mortality and not chronic disease or ethnicity in Croydon

  1. Zinu Philipose
  2. Nadia Smati
  3. Chun Shing Jefferson Wong
  4. Karen Aspey
  5. Michael Mendall

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Abstract

Background

Coronavirus-19 (COVID-19) mortality in hospitalised patients is strongly associated with old age, nursing home residence, male sex and obesity, with a more controversial association with ethnicity and chronic diseases, in particular diabetes mellitus. Further complicating the evaluation of the independent impacts of these risk factors is the failure to control for frailty in the published studies thus far.

Aim

To determine the true risk factors for mortality in patients confirmed to have COVID-19 in Croydon needing hospital admission and to evaluate the independence of these risk factors in this group after adjusting for body mass index (BMI) and frailty.

Methods

This observational study retrospectively reviewed hospital electronic medical records of 466 consecutive patients who were admitted to Croydon University Hospital confirmed positive by rapid PCR test from 11 th March 2020 to 9 th April 2020. Statistical analysis was performed by multiple unconditional and univariate logistic regression.

Results

After multivariate analysis, male sex [OR 1.44 (CI 0.92-2.40)], age (per year) [OR 1.07 (CI 1.05-1.09)], morbid obesity (BMI > 40 kg/m 2 vs reference BMI 18.5-24.9 kg/m 2 ) [OR 14.8 (CI 5.25-41.8)], and nursing home residence (OR 3.01 (CI 1.56-5.79) were independently associated with COVID-19 mortality with no statistically significant association found with chronic diseases or ethnicity. In the non-nursing home population, after adjusting for age and sex, the odds ratio for type 2 diabetes mellitus (T2DM) as a risk factor was 1.64 (CI 1.03-2.61, p = 0.03) and was and was attenuated to 1.30 (CI 0.78-2.18)) after controlling for BMI; the association of mortality with male sex was strengthened [OR 1.66 (CI 0.96-2.87)] and that for ethnic minority patients was weakened [South Asians [from OR 1.30 (CI 0.67-2.53)) to OR 1.21 (CI 0.60-2.46)]; African Caribbeans [from OR 1.24 (CI 0.65-2.34) to OR 1.16 (CI 0.58-2.30)]. There was a borderline but potentially large protective effect (p= 0.09) in patients who were on anticoagulation drugs prior to admission [OR 0.56 (CI 0.28-1.11)].

Conclusion

Our study found no significant effect of ethnicity and chronic diseases as independent risk factors on COVID-19 mortality in Croydon population whereas male sex, high BMI, old age and frailty were found to be independent risk factors. Routine prophylactic treatment with anticoagulant drugs in the high-risk COVID-19 population warrants further prompt investigation.

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  1. Version published to 10.1101/2020.08.12.20156257v3 on medRxiv
  2. Version published to 10.1101/2020.08.12.20156257v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2020.08.12.20156257: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    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: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    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.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  4. Version published to 10.1101/2020.08.12.20156257v1 on medRxiv