High-altitude is associated with better short-term survival in critically ill COVID-19 patients admitted to the ICU

Abstract Background: The novel human coronavirus, SARS-CoV-2, has affected at least 218 countries worldwide. Some geographical and environmental factors are positively associated with a better or worse prognosis concerning COVID-19 disease and with lower or higher SARS-CoV-2 transmission. High altitude exposure has been associated with lower SARS-CoV-2 attack rates; nevertheless, the role of chronic high-altitude exposure on the clinical outcome of critically ill COVID-19 patients has not been studied. Objective: To compare the clinical course and outcomes of critically ill patients with COVID-19 hospitalized in two intensive care units (ICU) located at low and high altitude. Exposure and Outcome: To explore the effect of two different elevations (10 m vs 2,850 m above sea level) on COVID-19 clinical outcome and survival. Methods: A prospective cohort, two-center study in confirmed COVID-19 adult patients admitted to a low altitude (Sea level) and high altitude (2,850 m) ICU units in Ecuador was conducted. Two hundred and thirty confirmed COVID-19 patients were enrolled from March 15th to July 15th, 2020. Sociodemographic, clinical, laboratory and imaging parameters including supportive therapies, pharmacological treatments and medical complications were reported and compared between the low and high-altitude groups. Results: The median age of all the patients was 60 years, 64.8% were men and 35.2% were women. A total of 105 (45.7%) patients had at least one underlying comorbidity, the most frequent being chronic diseases, such as hypertension (33.5%), diabetes (16.5%), and chronic kidney failure (5.7%). The APACHE II scale at 72 hours was especially higher in the low-altitude group with a median of 18 points (IQR: 9.5-24.0), compared to 9 points (IQR: 5.0-22.0) obtained in the group of high altitude. There is evidence of a difference in survival in favor of the high-altitude group (p = 0.006), the median survival being 39 days, compared to 21 days in the low altitude group. Conclusion: There has been a substantial improvement in survival amongst people admitted to the high-altitude critical care unit. Low altitude living was associated with improved survival, especially among patients with no comorbidities. COVID-19 patients admitted to the high-altitude ICU unit have improved severity-of-disease classification system scores at 72 hours and reported better respiratory and ventilatory profiles than the low altitude group.