Nonresponse or loss of response to anti-TNF occurs commonly in Crohn's disease. Clinical algorithms utilising therapeutic drug monitoring may establish the mechanisms for treatment failure and help guide the subsequent therapeutic approach.

ObjectiveUlcerative colitis (UC) is a dynamic disease with its severity continuously changing over time. We hypothesised that the risk of colorectal neoplasia (CRN) in UC closely follows an actuarial accumulative inflammatory burden, which is inadequately represented by current risk stratification strategies.DesignThis was a retrospective single-centre study. Patients with extensive UC who were under colonoscopic surveillance between 2003 and 2012 were studied. Each surveillance episode was scored for a severity of microscopic inflammation (0=no activity; 1=mild; 2=moderate; 3=severe activity). The cumulative inflammatory burden (CIB) was defined as sum of: average score between each pair of surveillance episodes multiplied by the surveillance interval in years. Potential predictors were correlated with CRN outcome using time-dependent Cox regression.ResultsA total of 987 patients were followed for a median of 13 years (IQR, 9-18), 97 (9.8%) of whom developed CRN. Multivariate analysis showed that the CIB was significantly associated with CRN development (HR, 2.1 per 10-unit increase in CIB (equivalent of 10, 5 or 3.3 years of continuous mild, moderate or severe active microscopic inflammation); 95% CI 1.4 to 3.0; P<0.001). Reflecting this, while inflammation severity based on the most recent colonoscopy alone was not significant (HR, 0.9 per-1-unit increase in severity; 95% CI 0.7 to 1.2; P=0.5), a mean severity score calculated from all colonoscopies performed in preceding 5 years was significantly associated with CRN risk (HR, 2.2 per-1-unit increase; 95% CI 1.6 to 3.1; P<0.001).ConclusionThe risk of CRN in UC is significantly associated with accumulative inflammatory burden. An accurate CRN risk stratification should involve assessment of multiple surveillance episodes to take this into account.

Summary Background Temporary faecal diversion is sometimes used for management of refractory perianal Crohn's disease (CD) with variable success. Aims To perform a systematic review with meta‐analysis to evaluate the effectiveness, long‐term outcomes and factors associated with success of temporary faecal diversion for perianal CD. Methods Through a systematic literature review through 15 July 2015, we identified 16 cohort studies (556 patients) reporting outcomes after temporary faecal diversion. We estimated pooled rates [with 95% confidence interval (CI)] of early clinical response, attempted and successful restoration of bowel continuity after temporary faecal diversion (without symptomatic relapse), and rates of re‐diversion (in patients with attempted restoration) and proctectomy (with or without colectomy and end‐ileostomy). We identified factors associated with successful restoration of bowel continuity. Results On meta‐analysis, 63.8% (95% CI: 54.1–72.5) of patients had early clinical response after faecal diversion for refractory perianal CD. Restoration of bowel continuity was attempted in 34.5% (95% CI: 27.0–42.8) of patients, and was successful in only 16.6% (95% CI: 11.8–22.9). Of those in whom restoration was attempted, 26.5% (95% CI: 14.1–44.2) required re‐diversion because of severe relapse. Overall, 41.6% (95% CI: 32.6–51.2) of patients required proctectomy after failure of temporary faecal diversion. There was no difference in the successful restoration of bowel continuity after temporary faecal diversion in the pre‐biological or biological era (13.7% vs. 17.6%, P = 0.60), in part due to selection bias. Absence of rectal involvement was the most consistent factor associated with restoration of bowel continuity. Conclusions Temporary faecal diversion may improve symptoms in approximately two‐thirds of patients with refractory perianal Crohn's disease, but bowel restoration is successful in only 17% of patients.

Treatment of chronic refractory pouchitis remains difficult and is largely empirical. Larger randomised controlled trials will help aid the management of chronic pouchitis.