Comparing the demographics and laboratory biomarkers of the COVID-19 Omicron wave and the Alpha wave in a predominantly Afro-Caribbean patient population in New York City.

Background: There is a knowledge gap of specific characteristics linked to disease severity of the different COVID-19 waves, especially in underserved populations. We compared the demographic and clinical factors associated with SARS-CoV-2-infected patients admitted to the intensive care unit (ICU) during the Omicron and Alpha waves.

Methods: An observational study comparing two COVID-19 waves was conducted in Brooklyn, NY. Twenty-seven ICU admitted patients with a positive COVID-19 test result during the period of November 1, 2021, to January 31, 2022, ("Omicron wave") were compared to 271 COVID-19 patients who received ICU consults during the Alpha wave, the period from March 28, 2020, to April 30, 2020.

Results: The Omicron wave had a 55.6% mortality rate compared to a 67.2% mortality rate in the Alpha wave. For the non-survivors, there were more females (66.7%) in the Omicron wave, while the trend was reversed in the Alpha wave (38.5%). Most of the patients seen were Black (> 85%) in both waves. A bivariate comparison of the two waves found that patients in the Omicron wave had overall significantly lower ALT levels (p = 0.03) and higher monocyte % (p = 0.005) compared to the patients in the Alpha wave. In the multivariate analysis, adjusting for age and sex, increasing levels of HCO3- were significantly associated with reduced mortality in the Omicron wave (OR: 0.698; 95% CI: 0.516 - 0.945; p = 0.02). Also, multivariable analyses using both waves combined found that neutrophil % was significantly associated with increased mortality (OR: 1.05; 95% CI: 1.02 - 1.09; p = 0.006) while lymphocyte % was significantly associated with reduced mortality (OR: 0.946; 95% CI: 0.904 - 0.990; p = 0.018).

Conclusions: The COVID-19-positive ICU patients in the Omicron wave experienced less severe outcomes than those of the Alpha wave. In contrast to the Alpha variant, the Omicron variant exhibited enhanced infectivity and disease severity in females.