M1139 Nationwide Referral Patterns to Specialized Medical Centers for the Inpatient Management of Inflammatory Bowel Disease

Abstract

BACKGROUND: The complexity of the medical and surgical management of inflammatory bowel disease (IBD) has increased substantially over the last decade. We sought to determine whether these secular advances have prompted changes in specialization of inpatient IBD care among high-volume centers. METHODS: We queried the Nationwide Inpatient Sample, a 20% stratified sample of U.S. hospital discharges throughout the U.S., to identify admissions with a primary diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) between 1998 and 2004. We calculated the proportion of admissions to specialized high-volume IBD centers (SHICs) (>100 IBD admissions per year), determined predictors of admission to SHICs, and assessed their impact on hospital outcomes. RESULTS: Over 7 years, the proportion of patients admitted to SHICs increased from 6.7% to 24%. IBD patients were less likely to be admitted to a SHIC if they were older (OR 0.88 for every 10 increase), female (OR 0.91; 95%CI: 0.86 0.96), were insured by Medicare (OR 0.74; 95%CI: 0.65 0.83) or Medicaid (0.71; 95%CI: 0.60 0.84), were uninsured (OR 0.42; 95%: 0.30 0.58), or were from the South (OR 0.43; 95%CI: 0.19 0.99 or West (OR 0.13; 95%CI: 0.04 0.45) relative to the Northeast. Factors favoring admission to a SHIC were residing in a neighborhood with above national median income (OR 1.99; 95%CI: 1.46 2.71), UC vs. CD diagnosis (OR 1.15; 95%CI: 1.05 1.26), and Black race (OR 1.44; 95%CI: 1.10 1.88). Compared to those admitted to non-SHICs, IBD patients admitted to SHICs were more likely to undergo colectomy for UC (8.8% vs. 19.9%, P<0.0001) or bowel resection for CD (16.4% vs. 25.2%, P<0.0001). These findings were similar after excluding elective surgical admissions. Though crude in-hospital mortality was considerably lower among those admitted to SHICs (4.3/1000 vs. 7.2/1000, P=0.0002), death rates were similar after adjusting for age and comorbidity. Adjusted mortality rates were, however, persistently lower in the SHIC group among those who had undergone colectomy (7.9/1000 vs. 32.4/1000, P=0.0002; adjusted OR 0.38). This mortality difference was primarily attributable to higher volumes of colectomy performed at SHICs. Average length of stay and hospital charges were similar between SHICs and non-SHICs after adjustment for patient and hospital demographics. CONCLUSIONS: There is a rising trend in referrals to SHICs for the inpatient management of IBD with disparate utilization patterns among socioeconomically defined subgroups. Prospective studies are warranted to further explore the impact of these high-volume centers on IBD health outcomes.