Healthcare resource utilization and costs associated with inflammatory bowel disease among patients with chronic inflammatory diseases: a retrospective cohort study

Abstract

Background: Chronic inflammatory diseases (CIDs; ankylosing spondylitis [AS], psoriatic arthritis [PsA], psoriasis [PsO], or rheumatoid arthritis [RA]) and inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) are associated with substantial economic burden. The relative increased costs among patients with CIDs and concomitant IBD compared to those without IBD is an important consideration when deciding on the clinical management of patient symptoms. Given the increasing use of novel agents for the treatment of CIDs, including those that may increase the risk of IBD in patients with CIDs, the objective of the study was to describe the incidence of IBD and to quantify healthcare resource utilization (HRU) and costs associated with IBD among patients with CIDs.

Methods: The IBM MarketScan® Research Databases (1/2010-7/2017) were used to identify adult patients with ≥2 claims with a diagnosis of either AS/PsA/PsO/RA (index date was a random claim for AS/PsA/PsO/RA). The one-year incidence rate of IBD was calculated following the index date. HRU and healthcare costs were compared between patients developing and not developing IBD in the year following the index date, adjusting for baseline characteristics.

Results: A total of 537,450 patients with CIDs (mean age = 54.0 years; 63.1% female) were included in the study. The 1-year incidence rate of IBD was 0.52% (range = 0.39% in patients with PsO but without PsA to 1.73% in patients with AS). Patients who developed IBD (N = 2778) had significantly higher rates of inpatient, outpatient, and emergency room visits (incidence rate ratios [IRR] = 2.91, 1.35, 1.81; all P < 0.0001), compared to patients without IBD (N = 534,672). Patients who developed IBD had $18,500 (P < 0.0001) higher total costs per year, including $15,121 (P < 0.0001) higher medical costs and $3380 higher pharmacy costs (P < 0.0001).

Conclusion: Higher HRU and costs were observed in patients with concomitant CID and IBD compared to patients with CID alone. Consideration should be given to treatment decisions that adequately manage CID and IBD to ensure optimal clinical and economic outcomes.

Keywords: Ankylosing spondylitis; Crohn’s disease; Healthcare costs; Healthcare resource utilization; Inflammatory bowel disease; Psoriasis; Psoriatic arthritis; Rheumatoid arthritis; Ulcerative colitis.

Fig. 1

Study design scheme. RA, rheumatoid arthritis; PsA, psoriatic arthritis; PsO, psoriasis; AS, ankylosing spondylitis

Fig. 2

Identification of the study population. RA, rheumatoid arthritis; PsA, psoriatic arthritis; PsO, psoriasis; AS, ankylosing spondylitis; IBD, inflammatory bowel disease. Notes: 1. Identified using the following ICD-9-CM and ICD-10-CM codes: RA (ICD-9-CM code 714.0; ICD-10-CM code: M05.1-M05.9, M06), PsA (ICD-9-CM code 696.0; ICD-10-CM code: L40.5x), PsO (ICD-9-CM code 696.1; ICD-10-CM code: L40.0-L40.4, L40.8, L40.9), or AS (ICD-9-CM code 720.0; ICD-10-CM code: M45.x)

Fig. 3

One-year incidence rate (a) and prevalence (b) of IBD by type of CID. CID, chronic inflammatory disease; RA, rheumatoid arthritis; PsA, psoriatic arthritis; PsO, psoriasis; AS, ankylosing spondylitis; IBD, inflammatory bowel disease

Fig. 4

Comparison of HRU during the 12-month observation period between patients developing versus not developing IBD. RA, rheumatoid arthritis; PsA, psoriatic arthritis; PsO, psoriasis; AS, ankylosing spondylitis; IBD, inflammatory bowel disease; HRU, healthcare resource utilization; IRR, incidence rate ratio; CI, confidence interval. * indicates that p-value < 0.05

Fig. 5

Comparison of costs during the 12-month observation period between patients developing versus not developing IBD. RA, rheumatoid arthritis; PsA, psoriatic arthritis; PsO, psoriasis; AS, ankylosing spondylitis; IBD, inflammatory bowel disease; MYCD, mean yearly cost difference; CI, confidence interval. * indicates that p-value < 0.05