Anemia prior to or during COVID-19 is a risk factor for rehospitalization after SARS-CoV-2 clearance
Abstract: As the number of new and recovering cases continues to rise, it is increasingly important to understand the long-term impacts of COVID-19 beyond the time of active SARS-CoV-2 infection. However, the clinical and molecular biomarkers characterizing patients who are likely to experience longer lasting effects after clearing SARS-CoV-2 are not yet known. We have found that COVID-19 patients hospitalized after confirmed viral clearance tended to have lower hemoglobin and hematocrit measurements both during their SARS-CoV-2 positive intervals and during the one year prior to COVID-19 diagnosis compared to patients who have not been rehospitalized after viral clearance. Further, outright laboratory-based diagnosis of moderate or severe anemia was strongly enriched in the hospitalized cohort, suggesting that anemia pre-dating or concurrent with SARS-CoV-2 infection may predispose patients to long-term complications of COVID-19. Interventions which may mitigate anemia did not reduce the risk of post clearance hospitalization, although the efficacy of and patient compliance with these interventions could not be established. This study demonstrates the value of integrated large-scale EHR analyses and highlights the need for further research to determine whether the prevention or mitigation of anemia during SARS-CoV-2 infection may reduce the risk of suffering long-term complications of COVID-19.