Polycythemia and COVID-19 mortality in patients at high altitude
Keywords:
altitude; cohort studies; COVID-19; hospital mortality; polycythemiaAbstract
Introduction: COVID-19 mortality shows considerable variability and may be influenced by comorbidities and geographic factors. In populations living at high altitude, secondary polycythemia represents an adaptation to chronic hypoxia; however, its relationship with COVID‑19 mortality remains unclear.
Objective: To evaluate the association between polycythemia and in-hospital mortality in hospitalized patients with COVID-19.
Methods: A retrospective analytical cohort study was conducted including 215 adults hospitalized with COVID-19 during 2021. Polycythemia was defined using altitude-adjusted hemoglobin levels. Descriptive analyses, cumulative incidence of mortality, calculation of relative risks (RR) in bivariate analysis, and binary logistic regression to obtain adjusted odds ratios (aOR) were performed.
Results: The median age was 57.4 years (IQR: 21); 58.6% were male. The prevalence of polycythemia was 3.3%. In-hospital mortality reached 27%. No evidence of an association between polycythemia and mortality was found. In bivariate analysis, age ≥ 60 years, type 2 diabetes, elevated D-dimer, C-reactive protein ≥ 7.5 mg/dL, elevated ferritin, and lymphopenia were associated with increased risk of death. In multivariable analysis, advanced age, diabetes, elevated D-dimer, and elevated C-reactive protein remained independent predictors.
Conclusions: Polycythemia at high altitude is not associated with COVID-19 mortality; however, age, diabetes, and inflammatory and thrombotic biomarkers do increase the likelihood of death.
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