Characteristics and Risk Factors for Mortality by COVID-19 Pandemic Waves in Fulton County, Georgia: A Cohort Study March 2020–February 2021

Abstract Background We examined differences in mortality among COVID-19 cases in the first, second and third waves of the COVID-19 pandemic. Methods A retrospective cohort study of COVID-19 cases in Fulton County, Georgia, USA, reported to a public health surveillance from March 2020 through February 2021. We estimated case fatality rates (CFR) by wave and used Cox proportional hazards random effects models in each wave, with random effects at individual and long-term-care-facility level, to determine risk factors associated with rates of mortality. Results Of 75,289 confirmed cases, 4,490 (6%) were diagnosed in wave one (CFR 31 deaths/100,000 person days [pd]), 24,293 (32%) in wave two (CFR 7 deaths/100,000 pd), and 46,506 (62%) in wave three (CFR 9 deaths/100,000 pd). Compared to females, males were more likely to die in each wave: Wave one (adjusted hazard ratio [aHR] 1.5, 95% confidence interval [CI] 1.2–1.8), wave two (aHR 1.5, 95% CI 1.2–1.8), and wave three (aHR 1.7, 95% CI 1.5–2.0). Compared to non-Hispanic Whites, non-Hispanic Blacks were more likely to die in each wave: Wave one (aHR 1.4, 95% CI 1.1–1.8), wave two (aHR 1.5, 95% CI 1.2–1.9), and wave three (aHR 1.7, 95% CI 1.4–2.0). Cases with any disability, chronic renal disease, and cardiovascular disease were more likely to die in each wave compared to those without these comorbidities. Conclusions Our study found gender and racial/ethnic disparities in COVID-19 mortality, and certain comorbidities associated with COVID-19 mortality. These factors have persisted throughout the COVID-19 pandemic waves, despite improvements in diagnosis and treatment.