Treatment Patterns and Healthcare Resource Use Among Patients With Axial Spondyloarthritis and Comorbid Inflammatory Bowel Disease

OBJECTIVES: Biologics approved for both axial spondyloarthritis (axSpA) and inflammatory bowel disease (IBD) may optimize outcomes among axSpA/IBD patients.

This research describes real-world characteristics and treatment patterns of newly diagnosed axSpA patients (stratified by comorbid IBD).

METHODS: Retrospective cohort study using IBM^® MarketScan^® database (Commercial and Medicare Supplemental). Eligible adults had ≥1 axSpA diagnosis from 01/2015–03/2020. Index was first recorded axSpA diagnosis with 12-month baseline. Patients were followed to end of study/loss of eligibility. Descriptive analyses performed.

RESULTS: Study included 397,735 axSpA patients, 2% (n=6,628) had baseline IBD (axSpA/IBD). Among axSpA/IBD patients, 55% had ulcerative colitis and 54% had Crohn’s disease (9% had ulcerative colitis/Crohn’s disease); mean age was 51 years, 63% were female, and 86% were commercially insured (88% had non-capitated health plans).

Among axSpA/IBD patients, mean (standard deviation) Charlson comorbidity index was 0.88 (1.40) versus 0.62 (1.21) for patients without IBD. axSpA/IBD patients had higher proportion of anxiety (24% versus 18%), chronic pulmonary disease (18% versus 15%), and mild liver disease (10% versus 4%) than patients without IBD. Prior medication use was greater among axSpA/IBD patients (opioids [53% versus 44%], corticosteroids [52% versus 34%], mesalamine derivatives [41% versus 1%], and biologics [28% versus 1%]).

Of axSpA/IBD patients who received biologics during follow-up (n=2,117), 88% received axSpA/IBD‑indicated biologics, 16% IBD-indicated, and 3% axSpA-indicated. Most patients maintained biologics for the same indications through follow-up (maintenance rates: 82% axSpA/IBD; 83% IBD; 68% axSpA).

Less than 1% of patients switched to biologics with different indication; 81% switched from axSpA/IBD- to IBD-indicated biologics. Among axSpA/IBD patients, 8% initiated biologics after index, of which 87% received axSpA/IBD‑indicated biologics.

CONCLUSIONS: Understanding treatment journey for axSpA/IBD patients may inform treatment decisions. axSpA/IBD patients had greater baseline disease burden versus patients without IBD. Most axSpA/IBD patients used axSpA/IBD‑indicated biologics during baseline and maintained through follow-up.