Risk of infection and hospitalization by Covid-19 in Mexico: a case-control study

  1. Jaime Berumen
  2. Max Schmulson
  3. Jesus Alegre
  4. Guadalupe Guerrero
  5. Gustavo Olaiz
  6. Rosa M. Wong-Chew
  7. Jorge Larriva-Sahd
  8. Carlos Cantu-Brito
  9. Ana Ochoa-Guzman
  10. Adrian Garcilazo-Avila
  11. Carlos Gonzalez-Carballo
  12. Erwin Chiquete

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Abstract

Objective. During the onset of a novel epidemic, there are public health priorities that need to be estimated, such as risk factors for infection, hospitalization, and clinical severity to allocate resources and issue health policies. In this work we calculate the risk of infection and hospitalization by Covid-19 conferred by demographic, lifestyle, and co-morbidity factors. Material and methods. This is a case-control study including the tested individuals for SARS-Cov-2 by RT-PCR officially reported by the Health Secretary of Mexico from January 01 to May 8, 2020 (102,875 subjects). Demographic (sex, age, foreign and immigrant status, native speaking, place of residence), life-style (smoking), and co-morbidities [diabetes, obesity, high blood pressure (HBP), asthma, immunosuppression, chronic obstructive pulmonary disease (COPD), cardiovascular disease other than HBP, chronic kidney disease (CKD), and other not specified diseases (other diseases)] variables were included in this study. The risk of infection and hospitalization conferred by each variable was calculated with univariate (ULR) and multivariate (MLR) logistic regression models. Results. The place of residence (OR=4.91 living in Tijuana City), followed by advanced age (OR=6.71 in 61-70 years-old), suffering from diabetes (OR=1.87) or obesity (OR=1.61), being male (OR=1.55), having HBP (OR=1.52), and notoriously being indigenous (OR=1.49) conferred a higher risk of becoming infected by SARS-CoV-2 in Mexico. Unexpectedly, we found that having asthma (OR=0.63), immunosuppression (OR=0.65) or smoking (OR=0.85) are protective factors against infection, while suffering from COPD does not increase the risk for SARS-CoV-2 infection. In contrast, advanced age (OR=11.6 in ≥ 70 years-old) is the main factor for hospitalization due to Covid-19, followed by some co-morbidities, mainly diabetes (OR=3.69) and HBP (OR=2.79), being indigenous (OR=1.89), male sex (OR=1.67) and the place of residence (OR=4.22 for living in Juarez City). Unlike the protective risk against infection, immunosuppression (OR=2.69) and COPD (OR=3.63), contribute to the risk of being hospitalized, while having asthma (OR=0.7) also provides protection against hospitalization. Conclusions. In addition to confirming that older age, diabetes, HBP and obesity are the main risk of infection and hospitalization by Covid-19, we found that being indigenous, immunosuppression, smoking and asthma protect against infection, and the latter also against hospitalization.

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    SciScore for 10.1101/2020.05.24.20104414: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: No informed consent was obtained as this was not an interventional study nor a direct survey of the study subjects.
    IRB: However, the Research and Ethics Committee of the Faculty of Medicine of the Universidad Nacional Autónoma de México was consulted, and they replied that ethical approval was not required.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variableFor sex, women were considered as the reference group.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    The statistical analyses were conducted using SPSS version 20 software (SPSS Inc., Chicago, IL, USA).
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    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:
    Strengths and weaknesses: The strengths of this work include the large size of the sample studied, the sampling of individuals at the national level in Mexico, and the analysis of the most important demographic data and comorbidities. However, important weaknesses are the lack of information on the outcomes of the disease and sociocultural data that may be important for the risk of infection, such as occupation, use of mass transit, attendance at mass events, and adherence to containment measures in the country. Discussion of findings and contrast with literature: It is interesting to note that the greatest risk of infection and hospitalization is conferred by cities with much trade with the USA (Tijuana and Juarez) and the port of Cancun, which is a massive gateway for foreign tourism to Mexico, both from the USA and Europe. This suggests that at these sites, at the beginning of the pandemic, there was a higher proportion of Covid-19 cases that were imported from abroad and were higher than in other regions of the country, subsequently favoring the pandemic expansion into the region. The metropolitan area, in the center of Mexico, including Mexico City and the State of Mexico, is the second most common place of residence conferring a risk of infection by SARS-Cov-2. However, while people living in Mexico City are less at risk of hospitalization, people living in the State of Mexico have 2-times greater risk than those living in the rest of the country, suggesting that by the...

    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.

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  2. Version published to 10.1101/2020.05.24.20104414 on medRxiv