Clinical characteristics and laboratory features of COVID-19 in high
altitude areas: A retrospective cohort study
Background: Coronavirus disease 2019 (COVID-19) is highly contagious and
has affected the whole world. We aim to investigate the clinical and
laboratory characteristics of COVID-19 patients in high altitude areas
of Sichuan, China. Methods: In this retrospective cohort study, a total
of 67 patients with laboratory-confirmed SARS-CoV-2 infection in Tibetan
Qiang Autonomous Prefecture of Ngawa, Sichuan were included from
February 1, 2020 to March 2, 2020. The clinical characteristics as well
as their radiological and laboratory features were extracted. Results:
4(6.0%) patients were categorized into severe cases, 39(58.2%) were
non-severe cases, and 24(35.8%) were asymptomatic cases. 46(68.7%)
patients were associated with cluster infection events in this study.
The most common symptoms were cough, sputum production, dyspnea, fatigue
or myalgia, and headache. 7(10.4%) patients showed leucopenia and 20
(29.9%) patients showed lymphopenia. Lymphocyte count and
neutrophil-to-lymphocyte ratio (NPR) was different between three groups.
14 (20.9%) patients had thrombocytopenia, prothrombin time (PT) and
fibrinogen levels differed between groups. We also found significant
difference of sodium, chloride, and calcium levels between three groups.
Antiviral therapy did not lead to obvious adverse event or shorter
duration from initial positive to subsequent negative nuclei acid tests.
Advanced age, hypertension, high neutrophil count,
neutrophil-to-lymphocyte ratio, fibrinogen, and lactate dehydrogenase
level were identified as independent risk factors for symptomatic cases
of COVID-19. Conclusions: The symptoms of patients in high altitude
areas were mild and about one third were asymptomatic. We also
identified several independent risk factors for symptomatic cases of