Clinical Predictors of Severe and Fatal COVID-19: Inflammatory and Haematological Biomarkers in Early Risk Stratification

Objectives Laboratory biomarkers have historically played a crucial role in clinical decision-making for infectious diseases. Therefore, investigating these biomarkers for COVID-19 risk classification is essential. This study aims to examine the influence of demographic factors, comorbidities, and laboratory biomarkers on the severity and mortality associated with COVID-19. Material and Methods A total of 2,184 patients from Makkah, Saudi Arabia (1,482 males and 702 females). This cohort study investigates the impact of demographic factors, comorbidities, and laboratory biomarkers, including coagulation and haematologic profiles, on COVID-19 severity and mortality. Results Key findings reveal that elevated inflammatory markers, including D-dimer (mean 4.3 ± 1.5 μg/mL in deceased), CRP (mean 189 ± 58 mg/dL in deceased), and ferritin, alongside coagulation profiles such as prothrombin time (PT), partial thromboplastin time (PTT), and international normalised ratio (INR), were strongly associated with severe outcomes or multiorgan failure. Older adults with comorbidities like hypertension, diabetes, and asthma showed higher mortality risks. Severe cases exhibited lower haemoglobin levels (mean 10.7 ± 1.3 g/dL) and red blood corpuscles (RBC) counts, indicating anaemia’s role in disease progression. Elevated white blood corpuscles (WBC) counts and neutrophilia were linked to critical cases, while lymphopenia, eosinopenia, and thrombocytopenia were common in severe and fatal cases. Conclusion The findings emphasise the utility of biomarkers for risk stratification and targeted treatments, underscoring the need for personalised care to improve patient outcomes.