Cost Effectiveness of Alternative Imaging Strategies for the Diagnosis of Small-Bowel Crohn's Disease

Abstract

The cost effectiveness of alternative approaches to the diagnosis of small-bowel Crohn's disease is unknown. This study evaluates whether computed tomographic enterography (CTE) is a cost-effective alternative to small-bowel follow-through (SBFT) and whether capsule endoscopy is a cost-effective third test in patients in whom a high suspicion of disease remains after 2 previous negative tests. A decision-analytic model was developed to compare the lifetime costs and benefits of each diagnostic strategy. Patients were considered with low (20%) and high (75%) pretest probability of small-bowel Crohn's disease. Effectiveness was measured in quality-adjusted life-years (QALYs) gained. Parameter assumptions were tested with sensitivity analyses. With a moderate to high pretest probability of small-bowel Crohn's disease, and a higher likelihood of isolated jejunal disease, follow-up evaluation with CTE has an incremental cost-effectiveness ratio of less than $54,000/QALY-gained compared with SBFT. The addition of capsule endoscopy after ileocolonoscopy and negative CTE or SBFT costs greater than $500,000 per QALY-gained in all scenarios. Results were not sensitive to costs of tests or complications but were sensitive to test accuracies. The cost effectiveness of strategies depends critically on the pretest probability of Crohn's disease and if the terminal ileum is examined at ileocolonoscopy. CTE is a cost-effective alternative to SBFT in patients with moderate to high suspicion of small-bowel Crohn's disease. The addition of capsule endoscopy as a third test is not a cost-effective third test, even in patients with high pretest probability of disease.