Background: Epidemiological data across the USA show health disparities in COVID-19 infection, hospitalization, and mortality by race/ethnicity. The state of New Mexico has the largest Hispanic and the third largest American Indian/Alaskan Natives (AI/AN) populations per capita in the United States. Complications from severe COVID-19 and mortality are largely unreported in diverse cohorts of hospitalized patients.

Methods: A retrospective observational study was conducted on adult (age>18 years) symptomatic COVID-19 patients admitted to the University of New Mexico Hospital (UNMH) from March 2020 to March 2021. Self-reported race/ethnicity, comorbidities, clinical and laboratory measures, and clinical events during hospitalization were obtained by manual chart review and aggregate data queries. Severe COVID-19 was defined as admission to the intensive care unit (ICU) and/or death throughout hospitalization, while non-severe patients did not require ICU support and survived. Statistical analysis for categorical variables was performed by Pearson’s Chi-Square, while continuous variables were analyzed using Kruskal-Wallis or two-way Anova. Binary logistic regression was used to determine COVID-19 complications associated with severe disease or mortality.

Results: The cohort was comprised of 1,425 symptomatic patients with laboratory-confirmed COVID-19. Patients were stratified by race/ethnicity: AI/AN (n=525), Hispanic (n=580), non-Hispanic White (NHW, n=214), and Others (Asian, African American, or chose not to disclose, n=108). The Other group was excluded from subsequent analyses. The average age of the cohort was 57.7±16.1 years, with 45.9% being female. The AI/AN group had the largest proportion of younger patients (aged 18-44, P< 0.001), while the NHW group had the oldest patients (age 65+, P< 0.001). At admission, NHW patients had significantly more comorbidities, including hypertension (P< 0.001), stroke (P< 0.001), chronic obstructive pulmonary disease (P< 0.001), hyperlipidemia (P< 0.001), and hypothyroidism (P< 0.001). The AI/AN group experienced higher rates of secondary bacterial pneumonia (SBP, P< 0.001), acute respiratory distress syndrome (ARDS, P=0.022), cardiac failure (CF, P< 0.001), and myocardial infarction (MI, P< 0.001). Predictors of severe COVID-19 included being male (OR=1.45, CI=1.07-1.98, P=0.018), AI/AN ancestry (OR=1.93, CI=1.23-3.02, P=0.004), SBP (OR=5.55, CI=3.68-8.36, P< 0.001), ARDS (OR=4.86, CI=2.59-9.13, P< 0.001), shock (OR=21.59, CI=11.43-40.77, P< 0.001), CF (OR=8.75, CI=4.69-16.37, P< 0.001), MI (OR=6.95, CI=3.66-13.17, P< 0.001), encephalopathy (OR=2.69, CI=1.58-4.59, P< 0.001), and AKI (OR=1.66, CI=1.09-2.53, P=0.018). Predictors of mortality were AI/AN ancestry (OR=1.74, CI=1.06-2.86, P=0.028), ARDS (OR=2.60, CI=1.56-4.34, P< 0.001), shock (OR=9.19, CI=5.88-14.35, P< 0.001), CF (OR=2.52, CI=1.37-4.63, P=0.003), MI (OR=4.15, CI=2.41-7.16, P< 0.001), and AKI (OR=2.01, CI=1.34-3.03, P< 0.001).

Conclusions: Severe COVID-19 and mortality in hospitalized patients at UNMH were associated with AI/AN ancestry, despite having comparable comorbidities and younger age. Consistent with elevated disease severity and mortality, the AIAN group also had higher rates of life-threatening complications resulting in longer hospitalization. Interventions aimed at reducing disparities in COVID-19 severity are important for improved public health in diverse communities.