High-altitude as factor associated with mortality in COVID-19 patients in Peru

Background: In December 2019 the first case of atypical pneumonia were reported in Wuhan-China due to SARS-CoV-2 virus. In the Andean population, adaptation mechanisms to hypoxic and hypobaric environmental condition would favor the decrease in mortality due to COVID-19. Aim: To determine whether altitude is a factor associated with mortality in COVID-19 patients in the Peruvian territory Methods: Observational case-control study analyzing secondary database. We measured association with chi(2) and multivariate analysis with simple and multiple logistic regression controlling for age, sex, severity and comorbidities (95%CI). Results: We analyzed data from 616.382 patients during the second wave in 26 regions of Peru (47.7% female and 52.3% male) with an average age of 42.7 +/- 18.2 years. The most frequent comorbidity was cardiovascular disease (4.5%), the most frequent symptom was cough (65.2%). In the bivariate analysis, age, sex, degree of severity and comorbidities were significant (p < 0.001; 95%CI) Multiple logistic regression showed that residing between 2,000-3,000 and 4,000-5,000 m a.s.l. provided a 62% and 32% lower probability of death compared to the population residing at less than 1,000 m a.s.l.; 95%CI OR: 0.38 (0.36-0.40) and OR 0.68 (0.59-0.80) respectively. Conclusion: In the Peruvian population, residing above 1,000 m a.s.l. is a protective factor against death from COVID-19.