1417: Common Causes of Hospitalization in Spondyloarthritis Patients: A Nationwide Analysis

Background/Purpose: Axial spondylarthritis (AxSpA), psoriatic arthritis (PsA), and inflammatory bowel disease-associated arthritis (IBD-A) are chronic inflammatory conditions with systemic involvement, leading to substantial morbidity and healthcare utilization. There is a paucity of national-level data on reasons for hospitalizations in patients with these conditions. We aimed to identify major diagnostic categories for hospitalizations and top reasons for hospitalization among patients with AxSpA, PsA, and IBD-A, using a large United States population-based database.

Methods: We conducted a retrospective cohort study using the National Inpatient Sample (NIS) from 2016 to 2020. The NIS is the largest inpatient hospitalization database in the U.S., representing 20% of hospitalizations from all non-federal acute care hospitals. We identified patients with a primary or secondary diagnosis of AxSpA, PsA, or IBD-A using ICD-10 codes. Principal diagnoses for hospitalization were analyzed and categorized into major diagnostic categories. Weighted analyses were performed to calculate national estimates of hospitalization reasons and determine the top principal diagnoses for each disease group.

Results: A total of 139,130 AxSpA, 223,745 PsA, and 1,880 IBD-A hospitalizations were analyzed. Demographics for the study cohort appear in Table 1. The top five most frequent major diagnostic categories for each group are summarized below [Table 2]:

• AxSpA: 1) Rheumatological disorder, 2) Injury/Poisoning, 3) Gastrointestinal disorders, 4) Cardiovascular disease, 5) Infections.


• PsA: 1) Cardiovascular disease, 2) Rheumatological, 3) Gastrointestinal disorders, 4) Infections, 5) Injury/Poisoning.


• IBD-A: 1) Gastrointestinal disorders, 2) Rheumatological disorder, 3) Infection, 4) Respiratory conditions, 5) Injury/Poisoning.

The leading principal diagnoses [Table 3] for AxSpA included sacroiliitis (7.6%), sepsis (5.3%), and acute renal injury (1.3%). For PsA, the top principal diagnoses included sepsis (6.5 %), primary osteoarthritis of the knee (3.5%), and non-ST-elevated myocardial injury (1.7 %). IBD-A population was most frequently admitted for ulcerative colitis (12.2%), followed by sepsis (10.6%), and then Crohn’s disease with and without complications (6.0%)

Conclusion: Hospitalization patterns in AxSpA, PsA, and IBD-A differ by disease type but share common themes of rheumatological, cardiovascular disease, infectious, injury/poisoning, and gastrointestinal involvement. These findings may highlight key areas for targeted management and preventive efforts to optimize healthcare resource utilization and improve quality care for patients