Inpatient Costs for Patients with Inflammatory Bowel Disease and Acute Pancreatitis

Abstract

Introduction: Inflammatory bowel disease (IBD) is associated with an increased risk of acute pancreatitis. Hospitalizations for acute pancreatitis in patients with IBD are anticipated to be more economically complex. Our group examined differences in length of stay (LOS) and costs for patients with IBD hospitalized for acute pancreatitis and the general population. Methods: A retrospective study of the 2005-2011 National Inpatient Sample (NIS) was conducted. The NIS is the largest publicly available inpatient healthcare database in the US. The primary diagnoses of acute pancreatitis and co-diagnoses of IBD, ulcerative colitis (UC) and Crohn's disease (CD) were identified by ICD-9 codes. Continuous variables were reported as mean ± standard deviations and compared between IBD and controls by two-sample T-tests or Wilcoxon rank-sum tests, with normality assumptions based on the Shapiro-Wilk test. Categorical variables were analyzed by Chi-square tests or Fisher's exact tests. Propensity score matching method is widely used in observational studies to reduce selection bias. To fairly compare the outcomes of interest, we conducted 1:3 propensity score matching using a matching algorithm based on following: Age, gender, race, numbers of co-morbidities, procedure number, insurance, income quartiles, hospital bed size, hospital location, region and teaching status. Statistical analyses were performed on SAS 9.3 (Cary, NC), Windows platform. Results: There were a total of 4,291 hospitalizations of IBD patients with acute pancreatitis over the 7 year period and 379,627 hospitalizations of non-IBD patients with acute pancreatitis. The mean LOS of patients with acute pancreatitis and a co-diagnosis of IBD was 5.7 days versus 4.9 days for controls (p < 0.0001). Hospital costs were higher in patients with IBD compared to controls ($29,724.89 vs. $27,916.76 respectively, p < 0.0001). Survival rates were high in both groups, but slightly lower in patients with IBD (99.4% vs. 99.3% respectively). Higher LOS and costs were seen in patients with acute pancreatitis and a co-diagnosis of CD or UC (table 1). Rate of alcohol abuse was lower and drug abuse was higher in patients with a co-diagnosis of IBD (table 2). Conclusion: Our study suggests that cost and length of stay in patients with acute pancreatitis is influenced by a co-diagnosis of IBD. A co-diagnosis of CD or UC incurs a greater economic burden in patients with acute pancreatitis.Figure 1Figure 2