<i>Letter to the Editor:</i> Influence of Altitude on the Prevalence and Case Fatality Rate of COVID-19 in Peru

Abstract

High Altitude Medicine & BiologyVol. 21, No. 4 Letters to the EditorFree AccessLetter to the Editor: Influence of Altitude on the Prevalence and Case Fatality Rate of COVID-19 in PeruClaudio Intimayta-Escalante, Daniel Rojas-Bolivar, and Ivan HanccoClaudio Intimayta-EscalanteAddress correspondence to: Claudio Intimayta Escalante, MS, Urb. El Asesor Mz. L - Lt. 12, Lima, Peru E-mail Address: [email protected]Sociedad Científica de San Fernando, Lima, Peru.Universidad Nacional Mayor de San Marcos, Lima, Peru.Search for more papers by this author, Daniel Rojas-BolivarCentro de Investigaciones Tecnológicas, Biomédicas y Medioambientales (CITBM), Callao, Peru.Search for more papers by this author, and Ivan HanccoLaboratoire de Hypoxie et Physiopathologie (HP2), Université Grenoble Alpes, Grenoble, France.Search for more papers by this authorPublished Online:21 Dec 2020https://doi.org/10.1089/ham.2020.0133AboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookXLinked InRedditEmail It has been observed that COVID-19 infection decreases in high-altitude regions (Arias-Reyes et al., 2020; Segovia-Juarez et al., 2020). However, the interaction between altitude and COVID-19 infection has not been examined in a follow-up study since the first case reported in each region. Therefore, our aim was to evaluate the influence of altitude and population density on the evolution of case fatality rate (CFR) and prevalence of COVID-19 in Peru.An ecological study was carried out. The observation units were the geographic regions. The dependent variables were the COVID-19 CFR (deaths per 100 COVID-19 cases) and prevalence (cases per 1,000 inhabitants), covariables were the altitude (meters) and population density (inhabitants per km2). The number of COVID-19–positive cases and deaths were obtained from the COVID-19 National Open Data Platform from March 03 to July 10, 2020. Population and altitude data were gathered from the National Population Census of 2017. The time was measured from the first COVID-19–positive case confirmed in each region. Longitudinal analysis was performed with a generalized estimation equation. Bivariate and multivariate analyses were performed.The COVID-19 prevalence and CFR means of regions ≥2,500 m were lower than the regions located <2,500 m (Fig. 1). In bivariate analysis, altitude was negatively associated with changes of COVID-19 prevalence (β = −6.0 × 10−3; p < 0.001). Population density did not affect the changes in COVID-19 prevalence (β = 3.2; p = 0.28). The altitude was negatively associated with COVID-19 CFR evolution (β = −8.5 × 10−6; p < 0.001), and there is an association between population density and COVID-19 CFR evolution (β = 2.7 × 10−2; p < 0.001). In multivariate analysis, altitude was negatively associated with changes in COVID-19 prevalence (β = −6.5 × 10−3; p < 0.001), but population density was not associated with changes of COVID-19 prevalence (β = −3.6; p < 0.24). Changes in COVID-19 CFR were affected by both altitude (β = −5.9 × 10−6; p < 0.001) and population density (β = 2.1 × 10−2; p < 0.001).FIG. 1. Distribution of COVID-19 infection by altitude. (A) Evolution of COVID-19 prevalence means by altitude. (B) Evolution of COVID-19 CFR means by altitude. The means of COVID-19 prevalence and CFR were lower in altitude ≥2,500 m. CFR, case fatality rate.Previous studies indicate the association between altitude and COVID-19 infection (Arias-Reyes et al., 2020; Segovia-Juarez et al., 2020). Our results give additional information about effect of altitude and population density on COVID-19 infection in a follow-up period of weeks from the first reported case in each region, which is important because of the unequal propagation of COVID-19 cases to altitude regions. There are factors that may explain this association such as ultraviolet radiation, chronic hypoxia, and ACE2 gene polymorphisms (Pun et al., 2020). However, there are other variables that should be evaluated, for example, socioeconomic status, distribution of diagnostic tests, and response capacity of the health system (Pun et al., 2020).This study has some limitations. The interpretation of the results applies to the regions, and they cannot be generalized to their inhabitants (ecological fallacy). Moreover, the statistical analysis was performed using the data of positive COVID-19 cases, but there is an excess of COVID-19 cases not confirmed by laboratory tests and all deaths for COVID-19 cannot be precisely counted for national systems in many countries such as Peru.In conclusion, changes in COVID-19 prevalence and CFR were affected by altitude.ReferencesArias-Reyes C, Zubieta-DeUrioste N, Poma-Machicao L, Aliaga-Raduan F, Carvajal-Rodriguez F, Dutschmann M, Schneider-Gasser EM, Zubieta-Calleja G, and Soliz J. (2020). Does the pathogenesis of SARS-CoV-2 virus decrease at high-altitude? Respir Physiol Neurobiol 277:103443. Crossref, Medline, Google ScholarGobierno del Peru. (2020). Plataforma nacional de datos abiertos. Available at: https://www.datosabiertos.gob.pe/group/datos-abiertos-de-covid-19 (accessed July 11, 2020). Google ScholarPun M, Turner R, Strapazzon G, Brugger H, and Swenson ER. (2020). Lower incidence of COVID-19 at high altitude: Facts and confounders. High Altit Med Biol [Ahead of Print]; DOI: 10.1089/ham.2020.0114. Link, Google ScholarSegovia-Juarez J, Castagnetto JM, and Gonzales GF. (2020). High altitude reduces infection rate of COVID-19 but not case-fatality rate. Respir Physiol Neurobiol 281:103494. 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Thomson, Fresia Casas, Harold Andre Guerrero, Rómulo Figueroa-Mujíca, Francisco C. Villafuerte, and Claudia Machicado23 June 2021 | High Altitude Medicine & Biology, Vol. 22, No. 2Negative Correlation between Altitude and COVID-19 Pandemic in Colombia: A Preliminary ReportThe American Journal of Tropical Medicine and Hygiene, Vol. 103, No. 6 Volume 21Issue 4Dec 2020 InformationCopyright 2020, Mary Ann Liebert, Inc., publishersTo cite this article:Claudio Intimayta-Escalante, Daniel Rojas-Bolivar, and Ivan Hancco.Letter to the Editor: Influence of Altitude on the Prevalence and Case Fatality Rate of COVID-19 in Peru.High Altitude Medicine & Biology.Dec 2020.426-427.http://doi.org/10.1089/ham.2020.0133Published in Volume: 21 Issue 4: December 21, 2020Online Ahead of Print:August 14, 2020PDF download

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