Immunodeficiency is prevalent in congenital heart disease and associated with increased risk of emergency admissions and death.

Aims: To provide population-based data on the prevalence and clinical significance of immune deficiency syndromes (IDS) associated with congenital heart disease (CHD).

Methods And Results: Utilizing administrative German Health System data the prevalence of increased susceptibility to infection (ISI) or confirmed IDS was assessed in CHD patients and compared with an age-matched non-congenital control group. Furthermore, the prognostic significance of IDS was assessed using all-cause mortality and freedom from emergency hospital admission. A total of 54 449 CHD patients were included. Of these 14 998 (27.5%) had ISI and 3034 (5.6%) had a documented IDS (compared with 2.9% of the age-matched general population). During an observation period of 394 289 patient-years, 3824 CHD patients died, and 31 017 patients experienced a combined event of all-cause mortality or emergency admission. On multivariable Cox proportional-hazard analysis, the presence of ISI [hazard ratio (HR): 2.14, P < 0.001] or documented IDS (HR: 1.77, P = 0.035) emerged as independent predictors of all-cause mortality. In addition, ISI and confirmed IDS were associated with a significantly higher risk of emergency hospital admission (P = 0.01 for both on competing risk analysis) during follow-up.

Conclusion: Limited immune competence is common in CHD patients and associated with an increased risk of morbidity and mortality. This highlights the need for structured IDS screening and collaboration with immunology specialists as immunodeficiency may be amenable to specific therapy. Furthermore, studies are required to assess whether IDS patients might benefit from intensified antibiotic shielding or tailored prophylaxis.