Age at ulcerative colitis (UC) diagnosis and at pouch surgery, a family history of inflammatory bowel disease (IBD), and previous smoking are risk factors for Crohn disease of the pouch (CDP) after ileal pouch-anal anastomosis (IPAA), according to a study in the Journal of Crohn’s and Colitis.
Researchers conducted a systematic review and meta-analysis to assess potential clinical predictors and risk factors associated with CDP in patients undergoing IPAA for UC.
A literature search was performed in the MEDLINE, EMBASE, EMCare, and CINAHL databases. Eligible studies reported predictive characteristics and outcomes on the development of CDP in patients with UC who underwent IPAA.
A total of 7 studies with 1,274 patients (767 patients with a normal pouch and 507 patients with CDP) were included. All the studies were retrospective, and 6 were from the United States.
The mean or median time to a diagnosis of CDP after IPAA ranged from 10.5 months to 72 months. The CDP group had a mean or median age of UC diagnosis of 20.5 to 28.0 years compared with 26.0 to 30.0 years in the normal pouch group. The mean or median age at pouch surgery was 26.0 to 36.0 years in the CDP group vs 36.0 to 40.0 years in the normal pouch group. The CDP group had a mean or median UC duration before pouch surgery of 48 to 96 months vs 72 to 109 months in the normal pouch group.
The patients’ age at UC diagnosis (weighted mean difference [WMD], -2.85; 95% CI, -4.39 to -1.31; P =.0003; I2=54%) and at pouch surgery (WMD, -3.17; 95% CI, -5.27 to -1.07; P =.003; I2=20%) was statistically significantly reduced in those who developed CDP, as was UC duration (WMD, -50.32; 95% CI, -101.10 to 0.46; P <.05; I2=55%).
A family history of IBD and CD was evaluated in 3 and 2 studies, respectively. Patients with CDP had a statistically higher rate of having a family history of IBD (odds ratio [OR], 2.43; 95% CI, 1.41-4.19; P =.001; I2=31%). A family history of CD alone was not associated with a higher incidence of CDP (OR, 1.18; 95% CI, 0.10-13.62; P =.90; I2=84%).
A history of smoking and current smoking were reported in 3 and 5 studies, respectively. Previous smoking was statistically significant in patients who developed CDP (OR, 1.80; 95% CI, 1.35-2.39; P <.0001; I2=0%), although current smoking was not (OR, 1.68; 95% CI, 0.92-3.06; P =.09; I2=0%).
In 4 studies, the indication for pouch surgery was reported. Pancolitis and fulminant colitis as indications for pouch surgery did not have statistical differences between the 2 groups. Dysplasia or cancer of the colon as an indication was associated with an increased risk for CDP (OR, 1.11; 95% CI, 0.05-0.23; P <.00001; I2=12%).
Limitations include the small number of studies. A majority were single-center, and no randomized controlled trials were included. Also, not all the studies reported on each aspect that was assessed in the meta-analysis.
“Patients should be counseled that if they develop a stricture or stenosis then their pouches may fail as a result, which may be secondary to CDP,” the study authors noted. “Future prospective studies are required to identify potential further risk factors for CDP and also understand the mechanisms at which they increase the risk of CDP.”
Fadel MG, Geropoulos G, Warren OJ, et al. Risks factors associated with the development of Crohn’s disease after ileal pouch-anal anastomosis for ulcerative colitis: a systematic review and meta-analysis. J Crohns Colitis. Published March 24, 2023. doi:10.1093/ecco-jcc/jjad051