The glutathione transferase Mu null genotype leads to lower 6-MMPR levels in patients treated with azathioprine but not with mercaptopurine.

The conversion of azathioprine (AZA) to mercaptopurine (MP) is mediated by glutathione transferase Mu1 (GSTM1), alpha1 (GSTA1) and alpha2 (GSTA2). We designed a case-control study with data from the TOPIC trial to explore the effects of genetic variation on steady state 6-methylmercaptopurine ribonucleotide (6-MMPR) and 6-thioguanine nucleotide (6-TGN) metabolite levels. We included 199 patients with inflammatory bowel disease (126 on AZA and 73 on MP). GSTM1-null genotype carriers on AZA had two-fold lower 6-MMPR levels than AZA users carrying one or two copies of GSTM1 (2239 (1006-4587) versus 4371 (1897-7369) pmol/8 × 108 RBCs; P<0.01). In patients on MP (control group) 6-MMPR levels were comparable (6195 (1551-10712) versus 6544 (1717-11600) pmol/8 × 108 RBCs; P=0.84). The 6-TGN levels were not affected by the GSTM1 genotype. The presence of genetic variants in GSTA1 and GSTA2 was not related to the 6-MMPR and 6-TGN levels.

Evaluation of long-term function, complications, quality of life and health status after restorative proctocolectomy with ileo neo rectal and with ileal pouch anal anastomosis for ulcerative colitis.

AIM: Restorative surgery after (procto)colectomy with ileo-neorectal anastomosis (INRA) or restorative proctocolectomy with ileal pouch anal anastomosis (RPC) combines cure of ulcerative colitis (UC) with restoration of intestinal continuity. This study aimed to evaluate these two operations. METHOD: Patients having INRA and RPC were matched according to sex, age at onset of UC, age at restorative surgery and duration of follow-up. Patients were included if they were over 18 years of age, had UC confirmed histopathologically and had undergone either operation. Long-term function, anal and neorectal physiology, complications, quality of life (QoL) and health status (HS) were determined. RESULTS: Seventy-one consecutive patients underwent surgery with the intention of having an INRA procedure. This was successfully carried out in 50, and 21 underwent intra-operative conversion to RPC. Median defaecation frequency was 6/24 h. In 11/71 patients reservoir failure occurred and 13/71 developed pouchitis. QoL and HS were comparable to the healthy population. Median follow-up was 6.2 years. These patients were matched with 71 patients who underwent RPC. RPC was successful in all patients. Median defaecation frequency was 8/24 h. Failure occurred in 7/71 patients and 13/71 developed pouchitis. QoL and HS were comparable with the healthy population. Median follow-up was 6.9 years. CONCLUSION: Comparison of INRA and RPC on an intention to treat basis was not considered to be realistic due to the high intra-operative conversion rate and the failures in the INRA group. RPC remains the procedure of choice for restoring intestinal continuity after proctocolectomy for UC.

Microalbuminuria is not a valuable marker for relapse in Crohn's disease.

BACKGROUND: Previous reports correlated microalbuminuria with disease activity in patients with Crohn's disease (CD). The aim of the present study is to determine the value of microalbuminuria as a marker for relapses in quiescent CD. METHODS: In a 1-year prospective maintenance trial with oral budesonide in patients with CD in remission, microalbuminuria was measured at randomization, after 2, 6 and 12 months, plus at the time of a relapse. The association of microalbuminuria with the course of disease was analyzed with logistic regression analysis. Time-dependent Cox regression was undertaken to study the association between microalbuminuria and relapse. RESULTS: We included a total of 139 patients. At randomization, microalbuminuria was present in 8 patients. During a 1-year follow-up, 29 patients relapsed and in 11% (3/29), microalbuminuria was present during the relapse. We found no statistically significant association between microalbuminuria and relapse (odds ratio 0.92, 95% confidence interval (CI) 0.76-1.13). Time-dependent Cox regression analysis also revealed no statistical predictive value for microalbuminuria (hazard ratio 1.29, 95% CI 0.37-4.39, p = 0.68). CONCLUSION: Microalbuminuria was moderately prevalent in quiescent CD patients, but it could not be associated with disease characteristics or the type of medication before randomization, nor as a predictor for relapses.

Molecular prediction of disease risk and severity in a large Dutch Crohn's disease cohort.

BACKGROUND: Crohn's disease and ulcerative colitis have a complex genetic background. We assessed the risk for both the development and severity of the disease by combining information from genetic variants associated with inflammatory bowel disease (IBD). METHODS: We studied 2804 patients (1684 with Crohn's disease and 1120 with ulcerative colitis) and 1350 controls from seven university hospitals. Details of the phenotype were available for 1600 patients with Crohn's disease and for 800 with ulcerative colitis. Genetic association for disease susceptibility was tested for the nucleotide-binding and oligomerisation domain 2 gene (NOD2), the IBD5 locus, the Drosophila discs large homologue 5 and autophagy-related 16-like 1 genes (DLG5 and ATG16L1) and the interleukin 23 receptor gene (IL23R). Interaction analysis was performed for Crohn's disease using the most associated single nucleotide polymorphism (SNP) for each locus. Odds ratios were calculated in an ordinal regression analysis with the number of risk alleles as an independent variable to analyse disease development and severity. RESULTS: Association with Crohn's disease was confirmed for NOD2, IBD5, DLG5, ATG16L1 and IL23R. Patients with Crohn's disease carry more risk alleles than controls (p = 3.85 x 10(-22)). Individuals carrying an increasing number of risk alleles have an increasing risk for Crohn's disease, consistent with an independent effects multiplicative model (trend analysis p = 4.25 x 10(-23)). Patients with Crohn's disease with a more severe disease course, operations or an age of onset below 40 years have more risk alleles compared to non-stricturing, non-penetrating behaviour (p = 0.0008), no operations (p = 0.02) or age of onset above 40 years (p = 0.028). CONCLUSION: Crohn's disease is a multigenic disorder. An increase in the number of risk alleles is associated with an increased risk for the development of Crohn's disease and with a more severe disease course. Combining information from the known common risk polymorphisms may enable clinicians to predict the course of Crohn's disease.

Genetic variants in the region harbouring IL2/IL21 associated with ulcerative colitis.

OBJECTIVES: Genetic susceptibility is known to play a large part in the predisposition to the inflammatory bowel diseases (IBDs) known as Crohn's disease (CD) and ulcerative colitis (UC). The IL2/IL21 locus on 4q27 is known to be a common risk locus for inflammatory disease (shown in coeliac disease, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus and psoriasis), while the roles that interleukin 2 (IL2) and IL21 play in the immune response also make them attractive candidates for IBD. The objective of this study was to test for association between the IL2/IL21 locus and the IBDs. METHODS: The four single nucleotide polymorphisms (SNPs) in the IL2/IL21 locus most associated with coeliac disease were genotyped in 1590 subjects with IBD and 929 controls from The Netherlands, and then replicated in a North American cohort (2387 cases and 1266 controls) and an Italian cohort (805 cases and 421 controls), yielding a total of 4782 cases (3194 UC, 1588 CD) and 2616 controls. Allelic association testing and a pooled analysis using a Cochran-Mantel-Haenszel test were performed. RESULTS: All four SNPs were strongly associated with UC in all three cohorts and reached genome-wide significance in the pooled analysis (rs13151961 p = 1.35 x 10(-10), rs13119723 p = 8.60 x 10(-8), rs6840978 p = 3.0 7x 10(-8), rs6822844 p = 2.77 x 10(-9)). A moderate association with CD was also found in the pooled analysis (p value range 0.0016-9.86 x 10(-5)). CONCLUSIONS: A strong association for the IL2/IL21 locus with UC was found, which also confirms it as a general susceptibility locus for inflammatory disease.

Lengthening adalimumab dosing interval in quiescent Crohn's disease patients: protocol for the pragmatic randomised non-inferiority LADI study.

INTRODUCTION: Adalimumab is effective for maintenance of remission in patients with Crohn's disease (CD) at a dose of 40 mg subcutaneously every 2 weeks. However, adalimumab is associated with (long-term) adverse events and is costly. The aim of this study is to demonstrate non-inferiority and cost-effectiveness of disease activity guided adalimumab interval lengthening compared to standard dosing of every other week (EOW). METHODS AND ANALYSIS: The Lengthening Adalimumab Dosing Interval (LADI) study is a pragmatic, multicentre, open label, randomised controlled non-inferiority trial. Non-inferiority is reached if the difference in cumulative incidence of persistent (>8 weeks) flares does not exceed the non-inferiority margin of 15%. 174 CD patients on adalimumab maintenance therapy in long-term (>9 months) clinical and biochemical remission will be included (C-reactive protein (CRP) <10 mg/L, faecal calprotectin (FC) <150 µg/g, Harvey-Bradshaw Index (HBI) <5). Patients will be randomised 2:1 into the intervention (adalimumab interval lengthening) or control group (adalimumab EOW). The intervention group will lengthen the adalimumab administration interval to every 3 weeks, and after 24 weeks to every 4 weeks. Clinical and biochemical disease activity will be monitored every 12 weeks by physician global assessment, HBI, CRP and FC. In case of disease flare, dosing will be increased. A flare is defined as two of three of the following criteria; FC>250 µg/g, CRP≥10 mg/l, HBI≥5. Secondary outcomes include cumulative incidence of transient flares, adverse events, predictors for successful dose reduction and cost-effectiveness. ETHICS AND DISSEMINATION: The study is approved by the Medical Ethics Committee Arnhem-Nijmegen, the Netherlands (registration number NL58948.091.16). Results will be published in peer-reviewed journals and presented at international conferences. TRIAL REGISTRATION NUMBERS: EudraCT registry (2016-003321-42); Clinicaltrials.gov registry (NCT03172377); Dutch trial registry (NTRID6417).

Colonoscopic surveillance improves survival after colorectal cancer diagnosis in inflammatory bowel disease.

BACKGROUND: Colonoscopic surveillance provides the best practical means for preventing colorectal cancer (CRC) in inflammatory bowel disease (IBD) patients. Strong evidence for improved survival from surveillance programmes is sparse. METHOD: The aim of this study was to compare tumour stage and survival of IBD patients with CRC who were a part of a surveillance programme with those who were not. A nationwide pathology database (PALGA (pathologisch anatomisch landelijk geautomatiseerd archief)) was consulted to identify IBD patients with CRC treated in all eight university hospitals in The Netherlands over a period of 15 years. Patients were assigned to the surveillance group when they had undergone one or more surveillance colonoscopies before a diagnosis of CRC. Patients who had not undergone surveillance served as controls. Tumour stage and survival were compared between the two groups. RESULTS: A total of 149 patients with IBD-associated CRC were identified. Twenty-three had had colonoscopic surveillance before CRC was discovered. The 5-year CRC-related survival rate of patients in the surveillance group was 100% compared with 74% in the non-surveillance group (P=0.042). In the surveillance group, only one patient died as a consequence of CRC compared with 29 patients in the control group (P=0.047). In addition, more early tumour stages were found in the surveillance group (P=0.004). CONCLUSIONS: These results provide evidence for improved survival from colonoscopic surveillance in IBD patients by detecting CRC at a more favourable tumour stage.

Guidelines for seagrass restoration: importance of habitat selection and donor population, spreading of risks, and ecosystem engineering effects.

Large-scale losses of seagrass beds have been reported for decades and lead to numerous restoration programs. From worldwide scientific literature and 20 years of seagrass restoration research in the Wadden Sea, we review and evaluate the traditional guidelines and propose new guidelines for seagrass restoration. Habitat and donor selection are crucial: large differences in survival were found among habitats and among donor populations. The need to preferably transplant in historically confirmed seagrass habitats, and to collect donor material from comparable habitats, were underlined by our results. The importance of sufficient genetic variation of donor material and prevention of genetic isolation by distance was reviewed. The spreading of risks among transplantation sites, which differed in habitat characteristics (or among replicate sites), was positively evaluated. The importance of ecosystem engineering was shown in two ways: seagrass self-facilitation and facilitation by shellfish reefs. Seagrass self-facilitative properties may require a large transplantation scale or additional measures.

High frequency of early colorectal cancer in inflammatory bowel disease.

BACKGROUND AND AIMS: To detect precancerous dysplasia or asymptomatic cancer, patients suffering from inflammatory bowel disease often undergo colonoscopic surveillance based on American or British guidelines. It is recommended that surveillance is initiated after 8-10 years of extensive colitis, or after 15-20 years for left-sided disease. These starting points, however, are not based on solid scientific evidence. Our aim was to assess the time interval between onset of inflammatory bowel disease (IBD) and colorectal carcinoma (CRC), and subsequently evaluate how many patients developed cancer before their surveillance was recommended to commence. METHODS: A nationwide automated pathology database (PALGA) was consulted to identify patients with IBD-associated colorectal carcinoma in seven university medical centres in The Netherlands between January 1990 and June 2006. Data were collected retrospectively from patient charts. Time intervals between onset of disease and cancer diagnosis were calculated in months. RESULTS: 149 patients were identified with confirmed diagnoses of IBD and CRC (ulcerative colitis n = 89/Crohn's disease n = 59/indeterminate colitis n = 1). Taking date of diagnosis as the entry point, 22% of patients developed cancer before the 8 or 15 year starting points of surveillance, and 28% if surveillance was commenced 10 or 20 years after diagnosis for extensive or left-sided disease, respectively. Using onset of symptoms to calculate the time interval, 17-22% of patients would present with cancer prior to the surveillance starting points. CONCLUSIONS: These results show that the diagnosis of colorectal cancer is delayed or missed in a substantial number of patients (17-28%) when conducting surveillance strictly according to formal guidelines.

[Current options for percutaneous endoscopic access to the digestive tract]. / Huidige mogelijkheden voor percutane endoscopische toegang tot de tractus digestivus.

Four patients, aged 67, 52, 56 and 64 years, respectively, undergoing percutaneous colostomy or jejunostomy are presented to illustrate current options for percutaneous endoscopic access to the digestive tract. The first patient had Parkinson's disease and required percutaneous jejunostomy for continuous post-pyloric administration of medication. The second patient had impaired gastric emptying due to gastric graft-versus-host disease following bone marrow transplantation. He was successfully treated with percutaneous jejunostomy, which was removed 2 years later after full recovery. The third patient had severe constipation due to the use ofmorphinomimetic analgesics. She received percutaneous caecostomy for colonic lavage and desufflation. The fourth patient had combined constipation and sphincteric insufficiency. Although the percutaneous endoscopic colostomy was clinically successful, the catheter had to be removed due to local pain and abscess formation.

Addition of simethicone improves small bowel capsule endoscopy visualisation quality.

BACKGROUND: Small bowel capsule endoscopy (SBCE) is an important diagnostic tool for small-bowel diseases but its quality may be hampered by intraluminal gas. This study evaluated the added value of the anti-foaming agent, simethicone, to a bowel preparation with polyethylene glycol (PEG) on the quality of small bowel visualisation and its use in the Netherlands. METHODS: This was a retrospective, single-blind, cohort study. Patients in the PEG group only received PEG prior to SBCE. Patients in the PEG-S group ingested additional simethicone. Two investigators assessed the quality of small-bowel visualisation using a four-point scale for 'intraluminal gas' and 'faecal contamination'. By means of a survey, the use of anti-foaming agents was assessed in a random sample of 16 Dutch hospitals performing SBCE. RESULTS: The quality of small bowel visualisation in the PEG group (n = 33) was significantly more limited by intraluminal gas when compared with the PEG-S group (n = 31): proximal segment 83.3% in PEG group vs. 18.5% in PEG-S group (p < 0.01), distal segment 66.7% vs. 18.5% respectively (p < 0.01). No difference was observed in the amount of faecal contamination (proximal segment 80.0% PEG vs. 59.3% PEG-S, p = 0.2; distal segment 90.0% PEG vs. 85.2% PEG-S, p = 0.7), mean small bowel transit times (4.0 PEG vs. 3.9 hours PEG-S, p = 0.7) and diagnostic yield (43.3% PEG vs. 22.2% PEG-S, p = 0.16). Frequency of anti-foaming agent use in the Netherlands was low (3/16, 18.8%). CONCLUSION: Simethicone is of added value to a PEG bowel preparation in improving the quality of visualisation of the small bowel by reducing intraluminal gas. At present, the use of anti-foaming agents in SBCE preparation is not standard practice in the Netherlands.

Heterozygosity for IL23R p.Arg381Gln confers a protective effect not only against Crohn's disease but also ulcerative colitis.

BACKGROUND: A recent study reported that a non-synonymous single nucleotide polymorphism (rs11209026, p.Arg381Gln) located in the IL23R gene is a protective marker for inflammatory bowel disease. AIM: To analyse the frequency of p.Arg381Gln in three independent European inflammatory bowel disease cohorts and to evaluate how this variant influences disease behaviour. METHODS: We assessed a European cohort of 919 inflammatory bowel disease patients and compared the IL23R p.Arg381Gln genotype frequency with 845 healthy controls. Inflammatory bowel disease patients originated from Germany [Crohn's disease (CD): n = 318; ulcerative colitis (UC): n = 178], Hungary (CD: n = 148; UC: n = 118) and the Netherlands (CD: n = 157). Ethnically matched controls were included. We performed subtyping analysis in respect to CARD15 alterations and clinical characteristics. RESULTS: The frequency of the glutamine allele of p.Arg381Gln was significantly lower in inflammatory bowel disease patients compared with controls in a pooled analysis of all three cohorts (P < 0.000001) as well as in the individual cohorts (Germany: P = 0.001, Hungary: P = 0.02 and the Netherlands: P = 0.0002). The p.Arg381Gln genotype distribution was similar between CD and UC. We did not observe either statistical interactions between p.Arg381Gln and CARD15 variants or any significant associations between p.Arg381Gln genotype and subphenotypes. CONCLUSIONS: The p.Arg381Gln IL23R variant confers a protective effect against both CD and UC, but does not determine disease phenotype.

Extended thiopurine metabolite assessment during 6-thioguanine therapy for immunomodulation in Crohn's disease.

The proposed metabolic advantage of 6-thioguanine (6-TG) is the direct conversion into the pharmacologically active 6-thioguaninenucleotides (6-TGN). The authors assessed metabolic characteristics of 6-TG treatment in patients with Crohn's disease (N = 7) on therapy with 20 mg 6-TG. 6-thioguanine-monophosphate (6-TGMP), 6-thioguanine-diphosphate (6-TGDP), and 6-thioguanine-triphosphate (6-TGTP) were measured by high-performance liquid chromatography analysis in erythrocytes. Thiopurine S-methyltransferase activity and total 6-TGN levels were determined by standard methods. High interindividual variance in metabolite measurements was observed. Main metabolites were 6-TGTP (median = 531 pmol/8 x 10(8) red blood cells) and 6-TGDP (median = 199 pmol/8 x 10(8) red blood cells). Traces of 6-TGMP (median = 39 pmol/8 x 10(8) red blood cells) and 6-TG (2 patients) could be detected. 6-TGN levels correlated with 6-TGTP levels (r = 0.929, P = .003) and with the sum of separate nucleotides (r = 0.929, P = .003). No correlations were established between TPMT activity (median = 13 pmol/h/10(7)) and 6-TG metabolites. The 1-step metabolism of 6-TG still leads to high interindividual variance in metabolite concentrations. Total 6-TGN level monitoring may suffice for clinical practice.

Maintenance treatment with budesonide 6 mg versus 9 mg once daily in patients with Crohn's disease in remission.

BACKGROUND: In previous trials, budesonide 6 mg/day was able to prolong the time to relapse in patients with quiescent Crohn's disease and budesonide 9 mg/day was effective in active disease with limited side effects. The aim of this study was to compare the effectiveness of budesonide 9 mg vs 6 mg once daily on the maintenance of remission and occurrence of adverse events. METHODS: Double-blind, randomised trial in patients with Crohn's disease in remission. Patients were randomised to receive 6 mg/day or 9 mg/day of budesonide (Budenofalk) without concomitant treatment for Crohn's disease. Endpoints were the time to relapse and relapse rates after one year. RESULTS: Seventy-six patients were randomised to 6 mg/day and 81 patients to 9 mg/day. Survival analysis showed no differences in the time to relapse. One-year relapse rates were not significantly different (6 mg group 24%; 9 mg group 19%). Any adverse event was reported in 61 and 68% of patients in the 6 mg and 9 mg groups, respectively; none of the 12 serious adverse events were drug related. CONCLUSION: The one-year relapse rates were low and not significantly different between the group of patients treated with budesonide 6 mg vs 9 mg/day. Also, time to relapse and the number of adverse events were similar in both treatment groups.

[Tracing colorectal carcinoma in patients with inflammatory bowel disease]. / Opsporing van colorectaal carcinoom bij patiënten met inflammatoir darmlijden.

In patients with ulcerative colitis the risk of colorectal cancer is increased. Based on a number of studies, British and American guidelines support endoscopic surveillance in these patients. As the cancer risk in ulcerative colitis increases with disease duration, it is recommended that surveillance is started 8-20 years after diagnosis depending on the extent of disease. Although previous studies have shown that the observed cancer risk in colonic Crohn's disease is unrelated to duration of disease, similar surveillance of these patients is suggested. A substantial number of cases of carcinoma in patients with inflammatory bowel disease present before scheduled onset of surveillance. Therefore, the optimal time of onset of surveillance is disputable. However, taking into account the relatively low risk of colorectal cancer in the early stages of inflammatory bowel disease, it will be hard to achieve an acceptable risk-benefit ratio of extending surveillance by starting surveillance colonoscopies at a younger age.

Risk factors for thiopurine-induced myelosuppression and infections in inflammatory bowel disease patients with a normal TPMT genotype.

BACKGROUND: Leucopenia is a common side effect in patients treated with thiopurines. Variants in the thiopurine S-methyltransferase (TPMT) gene are the best-known risk factor, but only explain up to 25% of leucopenia cases. AIM: To identify the clinical risk factors for thiopurine-induced leucopenia in patients without a common TPMT variant, and explore if these patients are at increased risk for infections. METHODS: Post hoc analysis of the Thiopurine response Optimisation by Pharmacogenetic testing in Inflammatory bowel disease Clinics (TOPIC) trial. For this analysis, patients without a variant in TPMT (*2, *3A or*3C) were included. Uni- and multivariate Cox-proportional hazard models were used to identify risk factors for leucopenia and infections. Leucopenia was defined as a white blood cell (WBC) count <3.0 × 109 /L and infections were classified according to the Common Terminology Criteria for Adverse Events. RESULTS: Sixty hundred and ninety-five patients (90.6%) included in the TOPIC-trial had no variant in TPMT, of which 45 (6.5%) developed leucopenia. Median time to leucopenia was 56 (29-112) days. Multivariate analysis showed that use of mercaptopurine compared to azathioprine was associated with leucopenia (hazard ratio [HR] 2.61 [95% CIs, 1.39-4.88; P < .01]) and a higher baseline WBC count was protective (HR 0.80 [95% CIs, 0.71-0.89; P < .01]). Risk factors for infections were older age (per 10 year; HR 2.07 [95% CIs, 1.18-3.63; P = .01]) and concomitant use of biologic drugs (HR 2.15 [95% CIs, 1.14-4.07; P = .02]). CONCLUSIONS: Low baseline WBC count and mercaptopurine, due to a relatively higher dose, were risk factors for thiopurine-induced leucopenia in patients without a TPMT variant.

Early prediction of thiopurine-induced hepatotoxicity in inflammatory bowel disease.

BACKGROUND: Hepatotoxicity, gastrointestinal complaints and general malaise are common limiting adverse reactions of azathioprine and mercaptopurine in IBD patients, often related to high steady-state 6-methylmercaptopurine ribonucleotide (6-MMPR) metabolite concentrations. AIM: To determine the predictive value of 6-MMPR concentrations 1 week after treatment initiation (T1) for the development of these adverse reactions, especially hepatotoxicity, during the first 20 weeks of treatment. METHODS: The cohort study consisted of the first 270 IBD patients starting thiopurine treatment as part of the Dutch randomised-controlled trial evaluating pre-treatment thiopurine S-methyltransferase genotype testing (ClinicalTrials.gov NCT00521950). Blood samples for metabolite assessment were collected at T1. Hepatotoxicity was defined by alanine aminotransaminase elevations >2 times the upper normal limit or a ratio of alanine aminotransaminase/alkaline phosphatase ≥5. RESULTS: Forty-seven patients (17%) presented hepatotoxicity during the first 20 weeks of thiopurine treatment. A T1 6-MMPR threshold of 3615 pmol/8 × 108 erythrocytes was defined. Analysis of patients on stable thiopurine dose (n = 174) showed that those exceeding the 6-MMPR threshold were at increased risk of hepatotoxicity: OR = 3.8 (95% CI: 1.8-8.0). Age, male gender and BMI were significant determinants. A predictive algorithm was developed based on these determinants and the 6-MMPR threshold to assess hepatotoxicity risk [AUC = 0.83 (95% CI: 0.75-0.91)]. 6-MMPR concentrations above the threshold also correlated with gastrointestinal complaints: OR = 2.4 (95% CI: 1.4-4.3), and general malaise: OR = 2.0 (95% CI: 1.1-3.7). CONCLUSIONS: In more than 80% of patients, thiopurine-induced hepatotoxicity could be explained by elevated T1 6-MMPR concentrations and the independent risk factors age, gender and BMI, allowing personalised thiopurine treatment in IBD to prevent early failure.

The Impact of Ethnicity and Country of Birth on Inflammatory Bowel Disease Phenotype: a Prospective Cohort Study.

BACKGROUND AND AIMS: The number of patients with inflammatory bowel disease [IBD], of non-Caucasian descent in Western Europe, is increasing. We aimed to explore the impact of ethnicity and country of birth on IBD phenotype. METHODS: IBD patients treated in the eight University Medical Centers in The Netherlands [Dutch IBD Biobank] were divided into two groups according to their ethnicity: 1] Caucasian patients of Western and Central European descent [CEU]; and 2] patients of non-Caucasian descent [non-CEU]. The non-CEU group was subdivided according to country of birth, into: born in The Netherlands or Western Europe [non-CEU European born]; or born outside Western-Europe who migrated to The Netherlands [non-CEU non-European born]. Both comparisons were analysed for phenotype differences [by chi-square test]. RESULTS: The Dutch IBD Biobank included 2921 CEU patients and 233 non-CEU patients. Non-CEU Crohn's disease [CD] patients more often had upper gastro-intestinal disease [16% vs 8%, p = 0.001] and anal stenosis [10% vs 4%, p = 0.002] than CEU CD patients. The use of anti-tumour necrosis factor [TNF] agents and immunomodulators was higher in non-CEU IBD patients than in CEU IBD patients [45% vs 38%, p = 0.042] and [77% vs 66%, p = 0.001], respectively. Non-CEU IBD patients born in Europe [n = 116] were diagnosed at a lower age than non-CEU IBD patients born outside Europe [n = 115] [at 22.7 vs 28.9 years old, p < 0.001]. CONCLUSION: Non-Caucasians had more severe disease behaviour than Caucasians. Non-CEU patients born in Europe were diagnosed at a lower age with IBD than those born outside Europe who migrated to The Netherlands.

Smoking is Associated with Higher Disease-related Costs and Lower Health-related Quality of Life in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Smoking affects the course of inflammatory bowel disease [IBD]. We aimed to study the impact of smoking on IBD-specific costs and health-related quality-of-life [HrQoL] among adults with Crohn's disease [CD] and ulcerative colitis [UC]. METHODS: A large cohort of IBD patients was prospectively followed during 1 year using 3-monthly questionnaires on smoking status, health resources, disease activity and HrQoL. Costs were calculated by multiplying used resources with corresponding unit prices. Healthcare costs, patient costs, productivity losses, disease course items and HrQoL were compared between smokers, never-smokers and ex-smokers, adjusted for potential confounders. RESULTS: In total, 3030 patients [1558 CD, 1054 UC, 418 IBD-unknown] were enrolled; 16% smoked at baseline. In CD, disease course was more severe among smokers. Smoking was associated with > 30% higher annual societal costs in IBD (€7,905 [95% confidence interval €6,234 - €9,864] vs €6,017 [€5,186 - €6,946] in never-smokers and €5,710 [€4,687 - €6,878] in ex-smokers, p = 0.06 and p = 0.04, respectively). In CD, smoking patients generated the highest societal costs, primarily driven by the use of anti-tumour necrosis factor compounds. In UC, societal costs of smoking patients were comparable to those of non-smokers. Societal costs of IBD patients who quitted smoking > 5 years before inclusion were lower than in patients who quitted within the past 5 years (€ 5,135 [95% CI €4,122 - €6,303] vs €9,342 [€6,010 - €12,788], p = 0.01). In both CD and UC, smoking was associated with a lower HrQoL. CONCLUSIONS: Smoking is associated with higher societal costs and lower HrQoL in IBD patients. Smoking cessation may result in considerably lower societal costs.

CARD15 in inflammatory bowel disease and Crohn's disease phenotypes: an association study and pooled analysis.

BACKGROUND: Three major polymorphisms of the Caspase-Activation Recruitment Domain containing protein 15 gene have been described to be associated with Crohn's disease. Genotype-phenotype studies reported in literature provide conflicting data on disease localisation and behaviour. We investigated the relation of Caspase-Activation Recruitment Domain containing protein 15 with inflammatory bowel disease and Crohn's disease phenotypic characteristics in a large Dutch cohort and performed a pooled analysis on inflammatory bowel disease patients and Crohn's disease phenotypic characteristics reported in association studies. METHODS: We genotyped 781 cases and 315 controls for the R702W, G908R and 1007fsinsC variants and for six microsatellite markers in and close to Caspase-Activation Recruitment Domain containing protein 15. In the pooled analysis data of 7201 inflammatory bowel disease patients and 3720 controls from 20 studies were included. RESULTS: Association was found for Crohn's disease with R702W and 1007fsinsC, including several disease characteristics, and not for ulcerative colitis. In the pooled analysis all three common Caspase-Activation Recruitment Domain containing protein 15 variants showed strong association with Crohn's disease (p<0.00001; odds ratio varying from 3.0 for single heterozygotes to 14.7 for compound heterozygotes) and not with ulcerative colitis. Phenotype analysis showed association with small bowel involvement, stricturing and penetrating disease. CONCLUSION: Caspase-Activation Recruitment Domain containing protein 15 is associated with Crohn's disease and not with ulcerative colitis. All three common Crohn's disease-associated variants are associated with small bowel involvement, the G908R and 1007fsinsC alleles also being associated with a complicated disease course.