Assessing the Prevalence of Anemia Post-COVID-19 Infection in Adult Members of a Southeastern U.S. Integrated Healthcare System

Abstract Background COVID-19 may cause or worsen anemia, leading to fatigue, lower quality of life, increased risk of comorbidities, and significantly associated with worse outcomes in patients hospitalized with COVID-19. Little is known among a community-based population. We aimed to investigate the incidence and risk factors of anemia post-COVID diagnosis in a community-based population. Methods We identified all adult members of KPGA with a confirmed diagnosis of COVID-19 between January 2020 and March 2022 and followed through March 2023. Anemia was defined using hemoglobin (Hgb) labs 180-days (±30-days) and 365-days (±30-days) after COVID-19 diagnosis and sex-specific thresholds. Potential risk factors included demographics and clinical characteristics (defined by diagnosis codes) at the time of COVID-19 diagnosis. Hospitalization with COVID-19 was used as a marker of COVID-19 severity. Logistic regression among individuals not diagnosed with anemia pre-COVID investigated the association between each risk factor and anemia 180- and 365-days post-COVID-19 infection. We stratified fully adjusted model by hospitalization with COVID-19 to assess effect modification. Results We included 3,450 and 3,043 individuals who met the inclusion criteria and had Hgb results available 180- and 365- days post-COVID-19 diagnosis. One-third of our population had anemia 180-days (n=1,100, 32.17%) and 365-days (n=1,007, 33.09%) post-COVID-19, with approximately 11% of the cohort being newly diagnosed cases of anemia. In the fully adjusted models females (vs. males) (OR=1.71, 95% CI: 1.42, 2.06), Black or African American individuals (vs. non-Black individuals) (OR=2.34, 95% CI: 1.98, 2.76), adults diagnosed with kidney disease (OR=1.79, 95% CI: 1.42, 2.25) or diabetes (OR=1.26, 95% CI: 1.12, 1.64), and adults hospitalized with COVID-19 (OR=1.43, 95% CI: 1.15, 1.78) were more likely to be diagnosed with anemia 365-days after COVID-19 diagnosis. Analyses stratified by hospitalization status showed a possible effect modification between hospitalization status and post-COVID-19 anemia. Discussion Our study showed that one in three people in a community-based population have anemia 180-days and 365-days after their first COVID-19 diagnosis. Anemia can cause fatigue, a lingering symptom of COVID-19 infection. Though more research is needed, ongoing surveillance of COVID-19 patients for anemia may be an important component of management of long COVID-19.