Aims of the study: To assess characteristics and the clinical course of nodular regenerative hyperplasia (NRH) in patients with inflammatory bowel disease (IBD) treated with azathioprine (AZA), so as to estimate the frequency of this complication and to search for risk factors.
Methods: Cases were identified through systematic survey of patients followed at 11 centers. At one center, cumulative risk of NRH was estimated and a case-control study was performed to identify risk factors.
Results: Thirty-seven cases of NRH (30 males, 7 females) were identified between 1994 and 2005. The median dose of AZA was 2 mg/kg/d (range, 1.5-3). The median time between start of AZA and diagnosis of NRH was 48 months (range, 6-187). After a median follow-up of 16 months (range, 1-138), 14 patients developed complications of portal hypertension. Using multivariate analysis, male gender and stricturing disease behavior were the two risk factors associated with NRH in patients treated with AZA. Cumulative risk calculated from the database at one center was 0.5 % at 5 years (95% CI: 0.11-0.89) and 1.25 % at 10 years (95% CI: 0.29-2.21).
Conclusion: NRH is a rare but potentially severe complication of AZA in patients with IBD. Clinicians should be aware of this complication, and should closely monitor liver function tests and platelet counts in their patients.
- inflammatory bowel disease
- nodular regenerative hyperplasia
- portal hypertension