Anemia is both common and independently associated with poor clinical outcomes in respiratory infections, including COVID-19.
Despite all the advances in COVID-19 vaccines and treatments, some patients still experience severe or fatal disease progression. Thus, there remains an impetus to identify any and all factors that may increase the risk of COVID-19 morbidity and mortality.
One study, presented this week at the 2023 European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), noted that evidence about the prevalence and prognosis of anemia in hospitalized COVID-19 patients is still ambiguous.
The investigators examined the association between COVID-19 patients’ anemia at hospital admission and incidence of severe disease and death.
The study authors referenced background information that anemia is known to be both a consequence of acute inflammation and a predictor of poor clinical outcomes in respiratory infections. In COVID-19 patients, the overexpression of overexpression of interleukin (IL)-1, IL-6, interferon-γ, and tumor necrosis factor (TNF)-α profoundly affect iron metabolism and erythropoiesis, which causes anemia.
This retrospective study was conducted in 2 teaching hospital in southern Italy. From September 1, 2020-August 31, 2022, the investigators collected data from all adult patients admitted for COVID-19. They determined the association between anemia, severe COVID-19, and in-hospital mortality using a Cox’s regression analysis.
“Anemia” was defined as a reduction in hemoglobin (Hb) <13 g/dl in men and <12 g/dl in women. “Severe COVID-19” was defined as admission to intensive or subintensive care unit, or a quick SOFA (qSOFA) score ≥2 or CURB-65 score ≥3. Using a propensity score, the association between anemia and mortality was adjusted in 2 models for the potential cofounders.
A total of 1562 patients were included in the analyses. Of the hospitalized COVID-19 patients, anemia prevalence was determined to be 45.1%. The patients were also significantly older, reported more comorbidities, and presented with higher levels of procalcitonin, CRP, ferritin, and IL-6.
The patients with anemia had a crude mortality incidence about 4 times higher than the hospitalized COVID-19 patients without anemia. After adjusting the results for 17 potential confounders, the investigators determined anemia significantly increased the risk of severe COVID-19 and death. These results were confirmed by the propensity score analysis.
The investigators concluded that anemia is associated with a more pronounced baseline proinflammatory profile in hospitalized COVID-19 patients, as well as a higher incidence of severe disease and in-hospital mortality.
This study, “Anemia as a predictor of poor clinical outcome in patients admitted for COVID-19: a large, multi-centre, retrospective cohort study,” was presented during a poster session at ECCMID 2023.