Differences in Prevalence of Haematological Abnormalities on Presentation to Hospital in COVID-19-Infected Adult and Paediatric Patients: A Retrospective Multicentre Descriptive Study

BACKGROUND: It is well known that COVID-19 infection affects multiple systems in the body. Reports have documented many changes in the hematopoietic system in the pathophysiology of the disease, and many haematological markers like lymphopenia and high d dimer have been linked to worse outcomes after COVID-19 infection in adult patients. AIM: The aim of the study was to find out the prevalence and any significant difference in routine haematological parameters on presentation in paediatric and adult patients with COVID-19 infection. METHODOLOGY: We conducted a multicentre retrospective descriptive observational study and investigated the prevalence of haematological abnormalities at the presentation of 1,000 PCR swab-confirmed COVID-19-infected randomly selected adult and paediatric patients admitted to 3 tertiary hospitals in Dubai from 15 March–30 May 2020. Data were gathered through their electronic medical records, and all analysis was done using the Statistical Package for the Social Sciences software (SPSS). RESULTS: The prevalence of at least one abnormal haematological parameter was 95.1% (794/835) on the first presentation to the hospital. After adjusting of age and gender, the prevalence of any white cell abnormality was 34.7% (290/835) (5.7% leukopenia, 9.6% leucocytosis, 25.4% lymphopenia, 5.5% neutropenia, 16.4% neutrophilia, 7.3% monocytosis, and 1.2% eosinopenia). A prevalence of 15.3% (128/835) anaemia, 9.5% (79/835) thrombocytopenia, and 4.3% (36/835) thrombocytosis was also observed. The prevalence of other abnormal blood parameters was C-reactive protein 69.5% (573/835), D dimer 57.5% (280/835), high lactate dehydrogenase 52% (383/835), high ferritin 72.1% (452/835), high international normalized ratio 5.1% (38/835), prolonged prothrombin time 32.2% (240/835), and prolonged activated partial thromboplastin time 35.6% (264/835). A significant difference in the prevalence of these abnormalities was evident between adult and paediatric populations, and these abnormalities were much more prevalent in adults but interestingly paediatric population tended to have a higher incidence of neutropenia, eosinophilia, and monocytosis (p < 0.001). CONCLUSION: COVID-19 infection tends to be milder and has better outcomes in the paediatric population. The immune system responds differently to the infection in these populations. The response is exaggerated in adults reflected by the increased prevalence of haematological abnormalities like raised inflammatory markers and other white cell abnormalities and has been linked with increased severity of infection and mortality.