Causes of Mortality in Patients with Inborn Errors of Immunity: An 18-year retrospective cohort study

Objectives: Inborn errors of immunity (IEI) are a diverse group of disorders arising from defects in the development and/or function of the immune system. However, data concerning the microbiological aspects of infections and direct causes of mortality in patients with IEI are limited and fragmented. This study aimed to elucidate the causes of disease and terminal events leading to death in a cohort of patients with IEI. Methods: This retrospective study included deceased patients who were diagnosed with primary immunodeficiency at Sultan Qaboos University Hospital in Muscat, Oman, over an 18-year period between 2005 and 2023. Data on clinical features, infections, isolated microorganisms and terminal events leading to death were collected and analyzed. Results: A total of 53 cases were included in this study. The mean age at death was 9.1 ± 10.4 years (median: 3.9 years, interquartile range: 15.2 years, range: 0.2–45.2 years). Prior to death, the most frequently isolated microorganisms included Pseudomonas spp. (41.5%), Pseudomonas aeruginosa (34%), Candida spp. (28.3%), cytomegalovirus (26.4%) and Hemophilus influenzae (20.8%), among others. The predominant terminal events leading to death were septicemia/septic shock (64.2%), pneumonia/adult respiratory distress syndrome/multiorgan dysfunction syndrome (49.1%), disseminated viral disease (22.6%) and bronchiectasis/pulmonary hypertension/haemorrhage (20.8%). Conclusion: Understanding factors contributing to terminal events in IEI patients can inform early intervention strategies and potentially reduce mortality rates.