The Prognostic Ability of On-Admission Hemoglobin Levels in Children with COVID-19: The PICU Experience at a Tertiary Hospital in Iran

Background: COVID-19 can lead to hematological abnormalities, including anemia. Pre-existing anemia can exacerbate the severity of the disease by increasing the peripheral tissue demand for oxygen. Both conditions can contribute to hypoxia. Objective: We aimed to investigate the relationship between COVID-19 infection and on-admission anemia in critically ill children and assess their effects on severe outcomes. Methods: This retrospective study was conducted at Children’s Medical Center during the COVID-19 pandemic. Patients were divided into two groups based on the first hemoglobin level: Anemic and non-anemic. For statistical analysis, we used univariate and multivariate logistic regression models in SPSS and Stata software. Results: A total of 133 patients were enrolled with a mean age of 63.2 months. Fifty-eight patients had anemia for age, and 75 were non-anemic. Among the patients, 53.5% of females and 35.6% of males were anemic (P = 0.04). Additionally, 50.5% of anemic patients had significant prehospital comorbidities compared with 20% of previously healthy patients (P = 0.03). Overall, 72.9% of patients survived, and 27.1% died. Using univariate analysis, death occurred significantly more in anemic patients compared to others (OR: 2.27, 95% CI: 1.042 - 4.948, P = 0.037). A logistic regression model was used to adjust the impact of potential confounders, showing that death occurred 1.82 times more often in anemic patients versus non-anemic patients (OR: 1.77, 95% CI: 0.79 - 3.98, P = 0.162). Furthermore, 54.9% of patients needed vasoactive agents, and 42.7% underwent mechanical ventilation (MV) (P = 0.413 and 0.155, respectively). Conclusions: The mortality rate in our study was 27.1%. In the logistic regression model adjusting for comorbidity and sex, we found a small effect relationship between anemia and mortality. However, wide confidence intervals and non-significant p-values indicate the low power of the study, mostly due to the small sample size. Further prospective studies with a larger sample size are recommended to determine the exact relationship between anemia and mortality.