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

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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was funding by the Universidad Nacional Autonoma de Mexico ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: No informed consent was obtained as this was not an interventional study nor a direct survey of the study subjects. This study was based solely on the analysis of a public national registry of subjects that have been tested for SARS-CoV-2 RT-PCR in Mexico. In addition, no personal identifications are present in this dataset therefore there is no bridge in the privacy of the study subjects. However, the Research and Ethics Committee of the Faculty of Medicine of the Universidad Nacional Autonoma de Mexico was consulted, and they replied that ethical approval was not required. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data generated or analysed during this study are included in this article.