Inpatient hospitalizations in adults with congenital heart disease and down syndrome: A national perspective.

Background: Adults with Down syndrome (DS) have a greater likelihood of being diagnosed with congenital heart disease (CHD) and may face unique cardiovascular, respiratory, and immunologic health burdens during hospitalization. While CHD survival has improved in recent decades, national data on hospitalization outcomes of patients diagnosed with DS remain limited. Objectives: The present study aimed to evaluate trends in hospital admissions, inpatient management, and perioperative outcomes stratified by the presence of DS among CHD patients. Methods: This was a retrospective cohort of the 2016-2022 National Inpatient Sample. All adult (18-64 years) hospitalizations with a diagnosis of congenital heart disease, were tabulated using previously validated International Classification of Diseases diagnosis codes. Our Primary outcome of interest was in-hospital mortality. Secondary endpoints included temporal trends in admissions, utilization of various cardiac procedures, and length of stay. Results: Of an estimated 54,410 CHD patients hospitalized, 3745 (6.9%) had diagnosis of DS. During the study period, annual CHD admissions increased (nptrend<0.05), while the proportion of those with DS remained stable (6.6% to 6.2%, 2016-2022; nptrend = 0.23). Patients with DS more commonly presented as having hypothyroidism, dementia, chronic obstructive pulmonary disease (all P < 0.05) and less frequently underwent cardiac procedures (7.6 vs 23.2%, P < 0.001). Following risk-adjustment, the presence of DS remained independently associated with greater odds of mortality among all hospitalizations (AOR 2.00, 95%CI 1.40-2.88, P < 0.001). Conclusions: Adults with DS and CHD represent a clinically vulnerable population with higher in-hospital mortality and lower procedural utilization. These findings underscore the need for dedicated care pathways to improve outcomes during medical admissions.