The Effect of Renin-Angiotensin-Aldosterone System Blocking Agents on the Long-term Disease Course of Patients With Crohn's Disease

BACKGROUND

The renin-angiotensin-aldosterone system (RAAS) has been associated with gastrointestinal inflammation and fibrosis, suggesting that RAAS blockade may be beneficial in patients with inflammatory bowel disease. Using retrospective analysis, we aimed to compare the disease course of patients with Crohn's disease (CD) taking two commonly prescribed classes of RAAS-blocking agents.

STUDY

Patients with CD initiated on an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) between 2000 and 2016 were enrolled. Data on clinical, radiologic, and procedural surrogate markers of inflammatory bowel disease were collected in the subsequent 3, 5, and 10 years and compared with matched controls using univariate and multivariate analyses.

RESULTS

Compared with controls, patients taking ARBs had fewer instances of corticosteroid use (1.06 vs 2.88, P < 0.01) at 10 years. Patients taking ACEIs had an overall worse disease course, with more imaging studies (3.00 vs 1.75, P = 0.03) and endoscopic procedures (2.70 vs 1.78, P = 0.01) at 5 years, and more imaging studies (6.19 vs 3.50, P < 0.01), endoscopic procedures (5.91 vs 3.78, P < 0.01), and gastrointestinal operations (0.59 vs 0.18, P < 0.02) at 10 years. Results remained significant on multivariate analysis, adjusting for CD characteristics and the use of other antihypertensive medications.

CONCLUSIONS

Our study provides insight into the long-term use of RAAS-blocking agents in patients with CD, suggesting that differences exist among commonly prescribed medication classes. While ACEIs were associated with an overall worse disease course at 5 and 10 years, patients taking ARBs were noted to have fewer instances of corticosteroid use at 10 years. Future large-scale studies are needed to further explore this association.

Improved Outcomes Associated With Teduglutide Use in Patients With Both Short Bowel Syndrome and Crohn's Disease

Introduction

Crohn's disease (CD) with short bowel syndrome (SBS) can present as chronic intestinal failure (CIF) often requiring nutritional support. Teduglutide is a treatment option for these patients. We investigated clinical outcomes of CD-CIF patients with SBS treated with teduglutide.

Methods

Adults with CD-CIF and SBS who received teduglutide were identified at a tertiary care academic center between 2012 and 2023. Data was collected retrospectively. Primary outcome measured was reduction in parenteral support (PS) by ≥20% volume, with PS defined as utilization of parenteral nutrition (PN) or intravenous fluids (IVF). Several secondary outcomes included immunosuppressive medication changes, subjective symptom improvement, and stool output.

Results

We identified 32 patients with CD-CIF and SBS receiving teduglutide. Comparing clinical outcomes before and after teduglutide, 26 of 32 patients achieved the primary outcome of ≥20% PS reduction. A decrease was seen in patients requiring PN + IVF, with corresponding increases in patients requiring PN only and IVF only. Among all 3 groups, a total of 23 patients received PN prior to teduglutide, which decreased to 14 following teduglutide. Weekly PN volume reduced from 7.00 to 3.55 L and weekly frequency decreased from 7.00 to 3.00 instances (P < .01). Reductions in weekly volume and frequency were observed among all patients receiving IVF support (25 vs 15). Secondary outcomes showed improvement in patient reported subjective symptoms (84.4%), stool output (90.6%), patients meeting criteria for diarrhea/high ostomy output (27 vs 14), and use of unique antidiarrheal medications (3.0 vs 2.0).

Conclusions

This retrospective case series demonstrated improved clinical outcomes in patients with CD-CIF and SBS treated with teduglutide resulting in decreased PS requirements, antidiarrheal medications requirement, and stool output without significant effects on immunosuppressive therapy.

Polygenic risk score predicts risk of primary sclerosing cholangitis in inflammatory bowel disease

BACKGROUND

Forty distinct primary sclerosing cholangitis (PSC) genomic loci have been identified through multiancestry meta-analyses. The polygenic risk score (PRS) could serve as a promising tool to discover unique disease behaviour, like PSC, underlying inflammatory bowel disease (IBD).

AIM

To test whether PRS indicates PSC risk in patients with IBD.

MATERIALS AND METHODS

Mayo Clinic and Washington University at St Louis IBD cohorts were used to test our hypothesis. PRS was modelled through the published PSC loci and weighted with their corresponding effect size. Logistic regression was applied to predict the PSC risk.

RESULTS

In total, 63 (5.6%) among 1130 patients with IBD of European ancestry had PSC. Among 381 ulcerative colitis (UC), 12% had PSC; in contrast to 1.4% in 761 Crohn disease (CD). Compared with IBD alone, IBD-PSC had significantly higher PRS (PSC risk: 3.0% at the lowest PRS quartile vs 7.2% at the highest PRS quartile, Ptrend =.03). In IBD subphenotypes subgroup analysis, multivariate analysis shows that UC-PSC is associated with more extensive UC disease (OR, 5.60; p=0.002) and younger age at diagnosis (p=0.02). In CD, multivariate analysis suggests that CD-PSC is associated with colorectal cancer (OR, 50; p=0.005).

CONCLUSIONS

We found evidence that patients with IBD with PSC presented with a clinical course difference from that of patients with IBD alone. PRS can influence PSC risk in patients with IBD. Once validated in an independent cohort, this may help identify patients with the highest likelihood of developing PSC.

Novel Genetic Risk Variants and Clinical Predictors Associated With Primary Sclerosing Cholangitis in Patients With Ulcerative Colitis

INTRODUCTION

Patients with ulcerative colitis (UC) who are likely to have primary sclerosing cholangitis (PSC) should be identified because PSC can influence UC clinical behavior and outcomes.The aim of this study was to establish a model incorporating clinical and genetic risk predictors that identifies patients with UC at risk of developing PSC.

METHODS

We conducted a retrospective case-control study. Inflammatory bowel disease cohorts from multiple institutions were used as discovery and replicate datasets. Quality control criteria, including minor allele frequency, call rates, Hardy-Weinberg equilibrium, cryptic relatedness, and population stratification (through principal components), were used. Discriminative accuracy was evaluated with area under the receiver operating characteristic curve.

RESULTS

Fifty-seven of 581 patients (9.8%) with UC had PSC. Multivariate analysis showed that patients with UC-PSC had more extensive disease (odds ratio [OR], 5.42; P = 1.57E-04), younger diagnosis age (younger than 20 years; OR, 2.22; P = 0.02), and less smoking (OR, 0.42; P = 0.02) than those with UC. After linkage disequilibrium pruning and multivariate analyses, 3 SNPs (rs3131621 at 6p21.33; rs9275596 and rs11244 at 6p21.32) at the HLA region were found associated with a 2- to 3-fold increased risk of PSC. Our model demonstrated good discriminatory power (area under the receiver operating characteristic curve, 88%).

DISCUSSION

Three variants in HLA (6p21.3) region significantly distinguished patients with UC-PSC from patients with UC alone. Once further validated in an independent large cohort, our model could be used to identify patients with UC at risk of PSC, and it could also help guide disease management.

Electronic Health Record Burden Amongst Gastroenterology Providers Associated with Sub-specialty and Training

Introduction Use of the electronic health record (EHR) has become increasingly widespread. Higher EHR burden is associated with burnout, but this has not been specifically investigated among gastroenterology (GI) providers. Methods We retrospectively collected measures of EHR use for outpatient GI providers during a 6-month period. We compared metrics across provider sex, sub-specialty, and training (physicians vs non-physician providers [NPPs]). Results Data collected represented over 16,000 appointments from 41 providers across the Division of Gastroenterology and Hepatology. Inflammatory bowel disease (IBD) and hepatology specialists spent more time per appointment in the EHR, clinical review, and outside regular hours compared to other sub-specialists. NPPs spent more EHR time than physicians. Conclusion IBD and hepatology specialists and NPPs may have disproportionally high EHR burden. More work is needed to understand differences in provider workload to combat burnout.

Efficacy of Hepatitis B Vaccination with a Novel Immunostimulatory Sequence Adjuvant (Heplisav-B) in Patients With Inflammatory Bowel Disease

BACKGROUND

Owing to the use of immunosuppressive agents, patients with inflammatory bowel disease (IBD) have an increased risk of vaccine preventable diseases, including infection with hepatitis B virus (HBV). Heplisav-B, an FDA-approved vaccine, is more effective (90% to 100%) than Engerix-B (70.5% to 90.2%) at inducing immunity to HBV in clinical studies. Available data on efficacy of Heplisav-B vaccine in patients with IBD are limited.

METHODS

This retrospective observational study included patients age 18 years and older with ulcerative colitis (UC) or Crohn's disease (CD) who received 1 or 2 doses of Heplisav-B vaccine and had postvaccination serologic testing. Prior to immunization, all participants were seronegative for HBsAb antibodies (HBsAb) measured as <10 IU/mL. Postvaccination HBsAb of ≥10 IU/mL was considered successful vaccination. Patient demographics, disease characteristics, and medications were abstracted.

RESULTS

One hundred six patients were included in the analysis. Median age was 43 years, and 44 (42%) were female. Thirty-nine patients (37%) had UC, whereas 67 (63%) had CD. Eighty-three patients (78.3%) had active immunity after vaccination with Heplisav-B, with median postvaccination HBsAb levels of 114 IU/L. Patients with chronic obstructive pulmonary disease, chronic kidney disease, diabetes mellitus, immunomodulator use, or those on 2 or more of immunosuppressive medications were less likely to respond to Heplisav-B, though these findings were not statistically significant on a multivariate analysis aside from chronic kidney disease.

CONCLUSIONS

Heplisav-B, a 2-dose vaccine, is an effective vaccine for HBV in patients with IBD. In our study, its overall efficacy (78.3%) is greater than that reported for the presently available 3-dose vaccination (Engerix) in patients with IBD.

Faecal Calprotectin from Ileostomy Output Is Sensitive and Specific for the Prediction of Small Bowel Inflammation in Patients with Crohn's Disease

BACKGROUND

Severe Crohn's disease [CD] can result in extensive bowel resections and need for creation of an ileostomy. Faecal calprotectin [FC] is well studied in CD management, though its role in patients who have an ileostomy is unclear. Our aim is to understand if FC is a useful adjunct to radiographic or endoscopic studies in identifying recurrent CD after surgery in patients with an ileostomy.

METHODS

Between January 1, 2017, and September 30, 2020, we searched the Mayo Clinic electronic medical record retrospectively for adult patients with ICD-10 code for CD, and a surgical history of an ileostomy. Patients were included in the analysis if they had at least one FC measured and a concomitant radiographic imaging and/or endoscopic procedure. An abnormal FC was defined as greater than 60 µg/g.

RESULTS

Of 51 patients who met our inclusion criteria, 17 had an FC level >60 µg/g. Of these 17 patients, 14 had imaging and/or an ileoscopy confirming the presence of small bowel inflammation, with a sensitivity of 87.5%. Of the remaining 34 patients with an FC level ≤60 µg/g, 32 patients had imaging and/or ileoscopy demonstrating no small bowel inflammation, with a specificity of 91.4%. FC from an ileostomy effluent had a positive predictive value of 82.3%, a negative predictive value of 94.1% and test diagnostic accuracy of 90.1%.

CONCLUSION

FC from an ileostomy effluent is a highly sensitive and specific test for the assessment and monitoring of small bowel inflammation and disease recurrence in patients with CD.

The use of ileal pouch-anal anastomosis in patients with ulcerative colitis from 2009 to 2018

AIM

The existing literature was updated, assessing the use of surgery in patients with ulcerative colitis in more recent years.

METHODS

This was a retrospective observational study identifying all patients with ulcerative colitis within the National Inpatient Sample, years 2009-2018. All patients with International Classification of Diseases, Ninth and Tenth Revisions, Clinical Modification diagnostic codes for ulcerative colitis were included. The primary outcome was the trend in total number of total abdominal colectomy, proctocolectomy and simultaneous versus delayed pouch construction.

RESULTS

A total of 1 184 711 ulcerative-colitis-related admissions were identified. An increase of 18.6% in the number of patients was observed, while the number of surgeries decreased. A total of 40 499 patients underwent total colectomy, annually decreasing from 5241 to 3185. The number of proctocolectomies without pouch decreased from 1191 to 530, while the number of patients undergoing pouch construction decreased from 2225 to 1284. The proportion of patients undergoing initial pouch at time of proctocolectomy decreased from 995 (45%) to 265 (21%), while the proportion of patients undergoing delayed pouch construction in 2018 was 79% (n = 1120).

CONCLUSION

Surgery use in ulcerative colitis has decreased in the last decade despite increasing numbers of hospital admissions in patients with this condition. While the overall proportion of patients undergoing pouch construction remained stable, the majority of patients were initially treated with total colectomy and their ileal pouches werre constructed in a delayed fashion.

Time to Flexible Sigmoidoscopy or Colonoscopy in Patients Admitted With Ulcerative Colitis Has Decreased From 2012 to 2018

Background

Early endoscopic evaluation of patients with ulcerative colitis (UC) enables assessment of disease activity and accurate diagnosis based on exclusion of other similarly presenting conditions including infections. Early endoscopy is also associated with improved outcomes of patients with active UC. The aim of this study was determining temporal trends in endoscopy in patients with UC over a 7-year period from 2012 to 2018.

Methods

Retrospective cohort study using the National Inpatient Sample 2012-2018. Patients admitted with ICD-9-10 principal codes for UC were included. Early endoscopy using flexible sigmoidoscopy (FS) or colonoscopy was defined as performed within 48 hours of admission. The primary outcome was trends in endoscopy timing. Secondary outcomes were inpatient morbidity, mortality, length of stay (LOS), and hospitalization charges/costs comparing patients undergoing early vs nonearly endoscopy using multivariable regression.

Results

Of 222 460 patients hospitalized with UC, 5900 (2.7%) underwent FS and 43 345 (19.5%) underwent colonoscopy. The rate of endoscopy increased from 3.9% (2.3% early) to 39.3% (23.3% early) from 2012 to 2018 (P < .01). Early endoscopy was associated with statistically significant decreased mortality, shock, multiorgan failure, and intensive care unit odds, as well as decreased resource utilization and LOS.

Conclusions

In patients hospitalized with UC, early endoscopy rates were low but performed more frequently from 2012 to 2018. This may reflect increasing awareness of improved outcomes from earlier disease staging and/or diagnosis. Early endoscopy was associated with decreased resource utilization and hospitalization-related outcomes, highlighting the importance of early endoscopy in patients admitted with UC.

Novel Genetic Variant Predicts Surgical Recurrence Risk in Crohn's Disease Patients

BACKGROUND

We aimed to identify a model of clinical and genetic risk factors through hypothesis-free search across genome that can predict the surgical recurrence risk after the first abdominal surgery in CD patients.

MATERIALS AND METHODS

Two independent inflammatory bowel disease (IBD) cohort studies were used to derive and validate the genetic risk profile. The study subjects were genotyped using Illumina Immunochip custom genotyping array. Surgical recurrence was defined as having the second or more abdominal bowel resections after the first abdominal surgery at the time of study enrollment; nonsurgical recurrence was defined as having no further abdominal resection after the first abdominal surgery.

RESULTS

Among 372 CD patients who had at least 1 abdominal surgery at the study enrollment, 132 (35.5%) had subsequent surgical recurrence after their first abdominal surgery, and 240 (64.5%) required no subsequent abdominal surgery at the end of follow up. Among clinical factors, multivariable analysis showed that history of immunomodulatory use (odds ratio [OR], 3.96; P = 0.002) and early era of CD first surgery (OR, 1.12; P = 1.01E-04) remained significant. Genotypic association tests identified a genome-wide significant locus rs2060886 in TCF4 at chr18q21.2 associated with surgical recurrence risk (OR, dom, 4.10 [2.37-7.11]; P = 4.58E-08).

CONCLUSIONS

Novel genetic locus rs2060886 in TCF4 was associated with surgical recurrence risk at genome-wide significance level among CD patients after their first abdominal surgery. Early era of CD first intestinal surgery predicts higher surgical recurrence risk. These results suggest that genetic variants may help guide the CD management strategy in patients at the highest risk of repeated abdominal surgeries.

Oral Contraceptive Pills Are an Effective Method of Preventing Pregnancy in Women With Crohn's Disease

Background

Oral contraceptive pill (OCP) use in the general population is associated with a failure rate as low as 0.3% with perfect use but as high as 9% with typical use. Women with Crohn's disease (CD) may have malabsorption in the setting of small bowel disease or resection, which could affect absorption of OCPs. Our aim was to determine the incidence of pregnancy in women with CD on OCPs.

Methods

This is a retrospective study assessing the incidence rate of OCP failure in females between 18 and 45 years of age seen at the Mayo Clinic with a diagnosis of CD and provided a prescription for OCPs, between 2016 and 2020. Failure was defined as clear documentation of becoming pregnant while using OCPs or having an active prescription of OCP at the time of conception.

Results

A total of 818 female patients with CD between 18 and 45 years of age with a prescription for an OCP were included in our study. Sixty-six patients (8%) conceived in this cohort. Of the 66 patients who became pregnant, 57 stopped the OCP before conceiving, 5 were excluded due to lack of data, and 4 women had active oral contraceptive prescriptions when they became pregnant (pregnancy rate of 0.5%).

Conclusions

In female patients with CD who are using OCPs for contraception, we found a low rate of pregnancy (0.5%) similar to the rate of pregnancy with perfect use of OCPs in the general population. OCPs are an effective method of birth control in women with CD.

Health Maintenance for Adult Patients with Inflammatory Bowel Disease

PURPOSE OF REVIEW

This review serves as a summary of healthcare maintenance items that should be addressed when managing patients with inflammatory bowel disease (IBD). This manuscript discusses vaccine-preventable illnesses, cancer prevention recommendations, and other screenings that are important to gastroenterologists and primary care physicians caring for patients with IBD.

RECENT FINDINGS

Patients with IBD often require immunomodulator agents and/or biologics to induce and maintain disease remission which can increase the risk of developing several infections. Also, subsets of patients with IBD are at an increased risk for a number of malignancies including colon, cervical, and skin cancers.

SUMMARY

Staying up-to-date with health care maintenance of patients with IBD is critical, especially given their increased risk for vaccine-preventable infections as well as comorbidities such as cancers, bone health, and mood disorders. Gastroenterologists and primary care physicians should familiarize themselves with the required screenings and vaccines that are recommended for adult patients with IBD, particularly those who are immunosuppressed.

COVID-19 polymerase chain reaction testing before endoscopy: an economic analysis

BACKGROUND AND AIMS

The novel coronavirus disease 2019 (COVID-19) pandemic has limited endoscopy utilization, causing significant health and economic losses. We aim to model the impact of polymerase chain reaction (PCR) testing into resuming endoscopy practice.

METHODS

We performed a retrospective review of endoscopy utilization during the COVID-19 pandemic for a baseline reference. A computer model compared 3 approaches: strategy 1, endoscopy for urgent indications only; strategy 2, testing for semiurgent indications; and strategy 3, testing all patients. Analysis was made under current COVID-19 prevalence and projected prevalence of 5% and 10%. Primary outcomes were number of procedures performed and/or canceled. Secondary outcomes were direct costs, reimbursement, personal protective equipment used, and personnel infected. Disease prevalence, testing accuracy, and costs were obtained from the literature.

RESULTS

During the COVID-19 pandemic, endoscopy volume was 12.7% of expected. Strategies 2 and 3 were safe and effective interventions to resume endoscopy in semiurgent and elective cases. Investing 22 U.S. dollars (USD) and 105 USD in testing per patient allowed the completion of 19.4% and 95.3% of baseline endoscopies, respectively. False-negative results were seen after testing 4700 patients (or 3 months of applying strategy 2 in our practice). Implementing PCR testing over 1 week in the United States would require 13 and 64 million USD, with a return of 165 and 767 million USD to providers, leaving 65 and 325 healthcare workers infected.

CONCLUSIONS

PCR testing is an effective strategy to restart endoscopic practice in the United States. PCR screening should be implemented during the second phase of the pandemic, once the healthcare system is able to test and isolate all suspected COVID-19 cases.

Unique Phenotypic Characteristics and Clinical Course in Patients With Ulcerative Colitis and Primary Sclerosing Cholangitis: A Multicenter US Experience

INTRODUCTION

Ulcerative colitis (UC) associated with primary sclerosing cholangitis (PSC) is a rare phenotype. We aimed to assess patients with UC-PSC or UC alone and describe differences in clinical and phenotypic characteristics, antitumor necrosis factor (TNF) therapy, and long-term clinical outcomes.

METHODS

This retrospective multicenter cohort study included patients who received a diagnosis of UC from 1962 through 2015. We evaluated clinical factors associated with UC-PSC vs UC alone and assessed associations by using multivariable logistic regression models.

RESULTS

Among 522 patients with UC, 56 (10.7%) had PSC. Compared with UC alone, patients with UC-PSC were younger (younger than 20 years) at diagnosis (odds ratios [OR], 2.35; adjusted P = 0.02) and had milder UC severity (adjusted P = 0.05), despite having pancolonic involvement (OR, 7.01; adjusted P < 0.001). In the biologics era (calendar year 2005 to 2015), patients with UC-PSC less commonly received anti-TNF therapy compared with patients with UC (OR, 0.38; adjusted P = 0.009), but their response rates were similar. Fewer patients with UC-PSC received corticosteroids (OR, 0.24; adjusted P = 0.005) or rectal 5-aminosalicyte acid (OR, 0.26; adjusted P < 0.001). Other differences were identified that were not statistically significant in a multivariable model: patients with UC-PSC more commonly were male, had lower rates of smoking, and had higher rates of colorectal cancer and colectomy.

DISCUSSION

This study identified a unique phenotype of UC with concurrent PSC, which had different clinical behavior compared with UC only. These phenotypic characteristics can help identify high-risk patients with UC before PSC is diagnosed and guide different management and monitoring strategies.

Targeting Mucosal Healing in Crohn's Disease

The goals of medical treatment for Crohn's disease are to induce remission and prevent long-term complications. The assessment of disease activity and response to therapy has moved beyond symptom-based measures to more objective ones, including mucosal healing. Studies of medical therapies target mucosal healing, or more accurately endoscopic remission, as an important treatment outcome. Mucosal healing leads to higher rates of sustained clinical remission and lower rates of hospitalization and disease-related surgery. Although an important goal, treating to the endpoint of mucosal healing has significant limitations. Studies validating mucosal healing are largely based on ileocolonoscopy, which is invasive and limits visualization to the colon and terminal ileum. Other tests, such as capsule endoscopy, noninvasive radiographic imaging, and serum and stool biomarkers, hold promise as alternatives, but more studies are needed. Although patients may demonstrate endoscopic response with optimization of the current medical therapies and the novel therapies under study, many patients do not attain mucosal healing. If there is clinical remission but incomplete mucosal healing after optimization of a therapy, it is not clear whether that therapy should be abandoned. However, despite these limitations, mucosal healing is an important treatment goal for the evaluation of new and existing therapies for Crohn's disease both in clinical studies and in practice.

Novel Genetic Risk Variants Can Predict Anti-TNF Agent Response in Patients With Inflammatory Bowel Disease

BACKGROUND

It is important to identify patients with inflammatory bowel disease [IBD] refractory to anti-tumour necrosis factor [TNF] therapy, to avoid potential adverse effects and to adopt different treatment strategies. We aimed to identify and validate clinical and genetic factors to predict anti-TNF response in patients with IBD.

MATERIALS AND METHODS

Mayo Clinic and Washington University IBD genetic association study cohorts were used as discovery and replicate datasets, respectively. Clinical factors included sex, age at diagnosis, disease duration and phenotype, disease location, bowel resection, tobacco use, family history of IBD, extraintestinal manifestations, and response to anti-TNF therapy.

RESULTS

Of 474 patients with IBD treated with anti-TNF therapy, 41 [8.7%] were refractory to therapy and 433 [91.3%] had response. Multivariate analysis showed history of immunomodulator use (odds ratio 10.2, p = 8.73E-4) and bowel resection (odds ratio 3.24, p = 4.38E-4) were associated with refractory response to anti-TNF agents. Among genetic loci, two [rs116724455 in TNFSF4/18, rs2228416 in PLIN2] were successfully replicated and another four [rs762787, rs9572250, rs144256942, rs523781] with suggestive evidence were found. An exploratory risk model predictability [area under the curve] increased from 0.72 [clinical predictors] to 0.89 after adding genetic predictors. Through identified clinical and genetic predictors, we constructed a preliminary anti-TNF refractory score to differentiate anti-TNF non-responders (mean [standard deviation] score, 5.49 [0.99]) from responders (2.65 [0.39]; p = 4.33E-23).

CONCLUSIONS

Novel and validated genetic loci, including variants in TNFSF, were found associated with anti-TNF response in patients with IBD. Future validation of the exploratory risk model in a large prospective cohort is warranted.

Crohn's Disease: Genetics Update

Since the discovery of the first Crohn's disease (CD) gene NOD2 in 2001, 140 genetic loci have been found in whites using high-throughput genome-wide association studies. Several genes influence the CD subphenotypes and treatment response. With the observations of increasing prevalence in Asia and developing countries and the incomplete explanation of CD variance, other underexplored areas need to be integrated through novel methodologies. Algorithms that incorporate specific genetic risk alleles with other biomarkers will be developed and used to predict CD disease course, complications, and response to specific therapies, allowing precision medicine to become real in CD.

Decreased Risk of Colorectal Cancer after Colonoscopy in Patients 76-85 Years Old in the United States

BACKGROUND/AIMS

The benefits of colonoscopy in reducing colorectal cancer (CRC) risk for patients over 75 years are controversial. We aimed to determine whether colonoscopy use is associated with a decreased risk of CRC in patients 76-85 years old in the United States (US).

PATIENTS AND METHODS

All patients in the Medicare 5% random sample of the Surveillance, Epidemiology and End Results-Medicare linked database 76-85 years old at outpatient colonoscopy between January 1, 1998 and December 31, 2002 were identified. Using the Kaplan-Meier method, we estimated the cumulative incidence of CRC in the above-mentioned colonoscopy group and compared with the control group of patients without colonoscopy. All patients were followed until diagnosis of CRC or carcinoma in situ, death or December 31, 2005. The multivariate Cox proportional hazards model was used in statistical analysis. CRC was separated by location into distal vs. proximal CRC in subgroup analysis.

RESULTS

Of 5,701 patients in the colonoscopy group, 37 (0.65%) patients were diagnosed with CRC, compared to 379 (1.55%) out of 24,437 patients in the control group (p < 0.001). The cumulative incidences of distal and proximal CRC were lower in the colonoscopy group compared to those in the control group (5-year distal CRC: 0.26 vs. 0.77%; 5-year proximal CRC: 0.43 vs. 0.79%, both p < 0.05). In multivariate Cox regression, colonoscopy was associated with decreased risk of all CRC (hazard ratio ((HR) 0.42, 95% CI 0.28-0.65), distal CRC (HR 0.36, 95% CI 0.18-0.70), and proximal CRC (HR 0.53, 95% CI 0.30-0.92)).

CONCLUSION

Among patients 76-85 years old in the United States, colonoscopy use was associated with decreased risks of both distal and proximal CRC, with a smaller risk reduction in distal colon. Due to inherent limitations associated with our retrospective design, future prospective studies are needed to validate these findings.

Use of surveillance colonoscopy in medicare patients with inflammatory bowel disease prior to colorectal cancer diagnosis

BACKGROUND

Patients with longstanding inflammatory bowel disease (IBD) involving large intestine proximal to rectum are considered to be at increased risk for colorectal cancer (CRC). One prior study showed low utilization of surveillance colonoscopy in patients with ≥ 8 years of ulcerative colitis (UC) in the USA.

AIMS

To study use of surveillance colonoscopy among Medicare beneficiaries with IBD in the 2-year period prior to CRC diagnosis.

DATA AND METHODS

Our study sample included Medicare beneficiaries in the SEER-Medicare-linked database who were diagnosed with CRC during 2001-2005 and had ≥ 3 physician visits with ICD-9 diagnosis code for IBD prior to CRC diagnosis. Medicare beneficiaries aged >85 years without Part B coverage or enrolled in HMOs were excluded. Colonoscopy performed within 6-30 months prior to CRC diagnosis was defined as surveillance colonoscopy. The χ² test and multivariate logistic regression were used in statistical analysis.

RESULTS

Of 241 Medicare beneficiaries with IBD and diagnosed with CRC, 92 (38%) patients underwent ≥ 1 surveillance colonoscopy in the 2 years prior to cancer diagnosis. The use of surveillance colonoscopy was similar between Crohn's disease (28/86, 33%) and UC (64/155, 41%). In multivariate logistic regression, older age (odds ratio (OR) 0.97, 95% confidence interval (CI) 0.94-0.99) was negative associated with surveillance colonoscopy use and personal history of colon polyp (OR 2.73, 95% CI 1.09-6.87) was positively associated with surveillance colonoscopy use.

CONCLUSIONS

Use of surveillance colonoscopy was low among Medicare beneficiaries with IBD in the 2 years prior to CRC diagnosis.

Chromocolonoscopy

Chromoendoscopy techniques improve the visualization of mucosal structures. This article reviews and summarizes key studies addressing the impact of chromoendoscopy on colonic neoplasia detection and differentiation of neoplastic from non-neoplastic polyps in average and high-risk populations, including patients with colonic inflammatory bowel disease (IBD). In this context, there are convincing data that chromoendoscopy differentiates neoplastic from non-neoplastic polyps in average-risk populations with high accuracy. Moreover, dye-based chromoendoscopy improves neoplasia detection in colonic IBD surveillance.

Racial/Ethnic and regional differences in the prevalence of inflammatory bowel disease in the United States

BACKGROUND

The magnitude of racial/ethnic and regional differences in the prevalence of inflammatory bowel disease (IBD) in the United States remains largely unknown.

AIMS

To estimate differences in the prevalence of IBD by race/ethnicity and region.

METHODS

The Medical Expenditure Panel Survey, a nationally representative survey of US households and medical conditions, was used. A multivariate logistic model was used in statistical analysis.

RESULTS

Among 202,468 individuals surveyed during 1996-2007, 316 were diagnosed with IBD (26 Blacks, 21 Hispanics, and 5 Asians). The prevalence of IBD was higher in Whites [Crohn's disease: 154; ulcerative colitis (UC): 89] than Blacks (Crohn's disease: 68; UC: 25), Hispanics (Crohn's disease: 15; UC: 35), and Asians (Crohn's: 45; UC: 40) (all p < 0.05, except for UC in Asians). The differences in Crohn's disease between Whites and minorities and the difference in UC between Whites and Blacks remained significant in multivariate analysis. In multivariate analysis, there was no regional difference in the prevalence of Crohn's disease, but the prevalence of UC was higher in the Northeast than the South (p < 0.05).

CONCLUSIONS

There were significant racial/ethnic differences in the prevalence of IBD in the USA. The underlying etiology of these differences warrants additional research.

Risk of colorectal cancer after colonoscopy compared with flexible sigmoidoscopy or no lower endoscopy among older patients in the United States, 1998-2005

OBJECTIVE

To determine whether the risk of colorectal cancer (CRC) decreases after colonoscopy compared with sigmoidoscopy or no lower endoscopy.

PATIENTS AND METHODS

Patients 67 to 80 years old in the 5% random Medicare sample of the Surveillance, Epidemiology and End Results and Medicare-linked database were grouped into those who underwent colonoscopy or flexible sigmoidoscopy from January 1, 1998, through December 31, 2002, and those who did not undergo lower endoscopy. We excluded patients with inflammatory bowel disease, history of colon polyps, or family history of CRC. All patients were followed up until the diagnosis of CRC or carcinoma in situ, death, or December 31, 2005. The risk of CRC after colonoscopy was compared with the risk after sigmoidoscopy or no lower endoscopy. The multivariate Cox proportional hazards model was used in statistical analysis.

RESULTS

In the colonoscopy group (n=12,266), 58 CRCs (0.5%) were diagnosed during follow-up compared with 66 CRCs (1.0%) in the sigmoidoscopy group (n=6402) and 634 (1.5%) in the control group (n=41,410) (all P<.001). In the sigmoidoscopy group, 771 patients (12.0%) underwent colonoscopy within the next 12 months. In multivariate Cox regressions, colonoscopy was associated with a decreased risk of distal CRC (hazard ratio [HR], 0.266; 95% CI, 0.161-0.437) and proximal CRC (HR, 0.451; 95% CI, 0.305-0.666); sigmoidoscopy was associated with a decreased risk of distal CRC (HR, 0.409; 95% CI, 0.207-0.809) but not proximal CRC.

CONCLUSION

Among older patients, the risk of distal CRC decreased after both colonoscopy and sigmoidoscopy; the risk of proximal CRC decreased after colonoscopy but not sigmoidoscopy.

Increased odds of interval left-sided colorectal cancer after flexible sigmoidoscopy compared with colonoscopy in older patients in the United States: a population-based analysis of the SEER-Medicare linked database, 2001-2005

OBJECTIVES

To compare the proportion of interval left-sided colorectal cancers (CRCs) after flexible sigmoidoscopy vs colonoscopy in older patients and to identify factors associated with interval CRC.

PATIENTS AND METHODS

Using the Surveillance, Epidemiology, and End Results-Medicare-linked database, we studied patients 67 years or older with left-sided CRC who had at least one lower endoscopy performed within the previous 36 months between July 1, 2001, and December 31, 2005. The CRCs diagnosed within 6 months of lower endoscopy were defined as detected CRCs; CRCs diagnosed 6 to 36 months after lower endoscopy were defined as interval CRCs. The proportion of interval CRCs was calculated as number of interval CRCs divided by number of detected and interval CRCs. The χ(2) test and a multivariate logistic regression model were used in the statistical analysis.

RESULTS

Of 15,484 older patients with left-sided CRC, the proportion of interval CRCs after flexible sigmoidoscopy was 8.8% compared with 2.5% after colonoscopy (P<.001). This difference was similar across left colon locations and largest in the descending colon (17.1% vs 3.5%; P<.001). In multivariate logistic regression, the odds of interval CRC after flexible sigmoidoscopy was 3 times as high as that after colonoscopy (odds ratio, 3.52; 95% CI, 2.66-4.65).

CONCLUSION

In older patients with left-sided CRC, the odds of interval CRC after flexible sigmoidoscopy was 3 times as high as that after colonoscopy. Whether this finding reflects differences in bowel preparation quality, sedation use, or depth of insertion warrants future research.

A comparison of high definition-image enhanced colonoscopy and standard white-light colonoscopy for colorectal polyp detection

BACKGROUND AND STUDY AIMS

Colonoscopy is widely used to detect and remove precancerous polyps, but fails to detect some polyps. Recent studies evaluating different image-enhanced methods have revealed conflicting results. The efficacy of colonoscopy imaging with simultaneous use of commercially available improvements, including high definition narrow band imaging (HD-NBI), and monochromatic charge-coupled device (CCD) video, was compared with a widely used standard definition white light (SDWL) colonoscopy system for detecting colorectal polyps. The primary aim was to determine whether the combination of image-enhanced colonoscopy systems resulted in fewer missed polyps compared with conventional colonoscopy.

PATIENTS AND METHODS

In a randomized controlled trial (Clinicaltrials.gov. study number NCT00825292) patients having routine screening and surveillance underwent tandem colonoscopies with SDWL and image-enhanced (HD-NBI) colonoscopy. The main outcome measurement was the per-polyp false-negative ("miss") rate. Secondary outcomes were adenoma miss rate, and per-patient polyp and adenoma miss rates.

RESULTS

100 patients were randomized and 96 were included in the analysis. In total, 177 polyps were detected; of these, 72 (41 %) were adenomatous. Polyp and adenoma miss rates for SDWL colonoscopy were 57 % (60/105) and 49 % (19/39); those for image-enhanced colonoscopy were 31 % (22/72) and 27 % (9/33) (P = 0.005 and P = 0.036 for polyps and adenomas, respectively). Image-enhanced and SDWL approaches had similar per-patient miss rates for polyps (6/35 vs. 9/32, P = 0.27) and adenomas (4/22 vs. 8/20, P = 0.11).

CONCLUSIONS

Utilization of multiple recent improvements in image-enhanced colonoscopy was associated with a reduced miss rate for all polyps and for adenomatous polyps. It is not known which individual feature or combination of image-enhancement features led to the improvement.

Inflammatory bowel disease in the elderly

This article reviews the epidemiology, clinical manifestations, diagnosis, prognosis, and treatment of inflammatory bowel disease (IBD), which will grow in prevalence as the population ages. Prognosis of late-onset ulcerative colitis (UC) is generally similar to that of early-onset UC, whereas in Crohn disease it is probably better because of a tendency for colonic involvement. Disease complications are related more to the duration of the inflammatory bowel disease than the subject's current age. The diagnosis in elderly patients can be challenging due to the large number of conditions that mimic IBD on radiologic, endoscopic, and histologic testing. Distinguishing these conditions from IBD will significantly alter prognosis and treatment. Complications related to IBD and its treatment are common and must be recognized early to limit their impact in a vulnerable elderly population.

Intestinal ischemia in the elderly

Mesenteric ischemia in the elderly is an uncommon but often fatal disorder for which the prognosis depends entirely on the speed and accuracy of the diagnosis. A high index of suspicion is required as the early signs and symptoms, at a time when ischemic changes are reversible, are typically nonspecific or absent. This article reviews the clinical spectrum of mesenteric ischemia in the elderly with particular emphasis on the varied presentations, evaluation, and management of ischemic disorders of the intestines.

An evidence-based review of natalizumab therapy in the management of Crohn's disease

Treatment options for Crohn's disease have evolved beyond the early goals of induction and remission and are now more focused on preventing complications by altering the natural history of the disease. The advent of biologic therapies has revolutionized the management of Crohn's disease. Specifically, antibodies to tumor necrosis factor alpha induce rapid mucosal healing. This translates into improved patient outcomes. However, many patients will fail these and other therapies. Natalizumab is a new biologic agent that has been approved for the treatment of moderately to severely active Crohn's disease in patients who have failed or are intolerant to immunosuppressants and/or tumor necrosis factor inhibitors. It is a selective adhesion molecule inhibitor to alpha-4 integrin resulting in inhibition of the migration of inflammatory cells across the endothelium. This unique mechanism of action has been shown to be effective in the treatment of Crohn's disease, making it an important option for otherwise refractory patients. Its use has been limited to these refractory patients because of concerns about the development of complications, especially progressive multifocal leukoencephalopathy. In this review, evidence-based data on the indications, efficacy and safety of natalizumab will be presented and its role in the management of patients with Crohn's disease will be defined.

Everything old is new again? A fresh look at corticosteroids in ulcerative colitis

Corticosteroid therapy remains a mainstay in the treatment of active ulcerative colitis. While useful in the induction of remission, corticosteroids should be avoided for maintenance therapy because of lack of efficacy and serious short- and long-term side effects. Bone fracture risk is increased with as little as 3 months of therapy so that safer corticosteroid therapies would have a significant impact. In this issue of American Journal of Gastroenterology, the treatment of mild to moderate ulcerative colitis with dexamethasone 21-P encapsulated erthryocytes (DEE), a novel method of corticosteroid drug delivery, is described. The results suggest similar efficacy as conventional oral corticosteroids with significantly decreased short-term corticosteroid-related side effects. This study was small and follow-up was limited, but the findings are intriguing. These results should prompt further study of this method of drug delivery to confirm efficacy, assess short-term and possibly long-term side effect, and determine whether this translates into better overall safety.

Rifaximin for the treatment of active pouchitis: a randomized, double-blind, placebo-controlled pilot study

BACKGROUND

The efficacy of the nonabsorbable antibiotic rifaximin in patients with active acute or chronic pouchitis is unknown.

METHODS

We performed a placebo-controlled pilot trial to evaluate the efficacy and safety of rifaximin in patients with active pouchitis. Eighteen patients with active pouchitis were randomized to receive oral rifaximin 400 mg or placebo 3 times daily for 4 weeks. Active pouchitis was defined as a total Pouchitis Disease Activity Index (PDAI) score = 7 points. Clinical remission was defined as a PDAI score <7 points and a decrease in the baseline PDAI score = 3 points. The primary analysis was clinical remission at week 4.

RESULTS

Eight patients were randomized to rifaximin and 10 patients were randomized to placebo. One patient in the placebo group did not have a post-baseline efficacy evaluation and was excluded from the efficacy analysis. Two of 8 patients (25%) treated with rifaximin were in clinical remission at week 4 compared to 0 of 9 patients (0%) treated with placebo (P = 0.2059). None of 8 patients in the rifaximin group withdrew from the trial prior to week 4. Two of 9 patients in the placebo group withdrew prior to week 4 due to lack of efficacy and were categorized as treatment failures.

CONCLUSIONS

Clinical remission occurred more frequently in patients treated with rifaximin 400 mg 3 times daily but the difference was not significant in this pilot study. A larger trial would be required to determine if rifaximin is effective for the treatment of active pouchitis. Rifaximin was well tolerated.

New studies on the role of smoking in inflammatory bowel disease: are we not beating a dead horse?

The role of smoking in inflammatory bowel disease (IBD) has drawn more interest as our understanding of these diseases has moved beyond the simple designations of Crohn's disease (CD) and ulcerative colitis (UC). In this issue of the journal, Aldous et al. present two papers on the role of smoking in the heterogeneity of IBD. They confirm the findings of many, are at odds with the findings of some, and provide novel observations for us all as we try to understand this complex interaction. Do these studies provide more clarity or just add to the noise? As always, the devil is in the details.

Oral mesalamine and clinical remission are associated with a decrease in the extent of long-standing ulcerative colitis

OBJECTIVE

To compare colonoscopy alone with surveillance biopsy for the determination of anatomic extent in long-standing ulcerative colitis (UC). To assess the influences of mesalamine use and clinical disease activity on the change of histologic extent with time.

MATERIALS AND METHODS

Disease extent (proctosigmoiditis, left-sided colitis, or pancolitis) measured by colonoscopy and surveillance biopsy was compared among 212 consecutive patients with long-standing UC. Among the 102 patients who had 2 consecutive colonoscopies with surveillance biopsies, the following influences on change in histologic extent were determined: disease activity, mesalamine use, age at disease onset, folic acid, corticosteroid and azathioprine/6-mercaptopurine use, and time between colonoscopies.

RESULTS

Agreement between gross and microscopic findings was poor (kappa = 0.39). Colonoscopy underestimated and overestimated extent in 25.9% and 8.5%, respectively. Microscopic distribution between consecutive colonoscopies remained the same in 60.8%. Where distribution changed, an increase was twice as common as a decrease in extent. There was no difference in age at onset, time between colonoscopies, or disease duration among those with an increase, decrease, or no change in extent. Clinical remission and oral mesalamine were independently associated with 10.7 and 5.8 times the odds of a decrease in disease extent, respectively. Folic acid, topical mesalamine, corticosteroids, and immunomodulators did not influence change in extent.

CONCLUSIONS

UC extent is best determined by surveillance biopsy. Among patients with long-standing UC, histologic extent fluctuates with time. Disease remission and oral mesalamine were independently associated with decreases in disease extent.

Defining complex contributions of NOD2/CARD15 gene mutations, age at onset, and tobacco use on Crohn's disease phenotypes

BACKGROUND

Multiple factors, particularly IBD family history, tobacco use, age at diagnosis and recently, NOD2 mutant genotypes may influence Crohn's disease (CD) heterogeneity.

METHODS

We performed a multicenter retrospective record analysis of 275 unrelated patients with CD. Age at diagnosis, IBD family history, Jewish ethnicity, tobacco use at diagnosis, surgical history, disease site and clinical behavior were correlated with genotypes for NOD2 mutations, and all risk factors were assessed for independent influence on outcomes of disease site, behavior and surgery free survival.

RESULTS

Risk of ileal disease was increased for CD patients with two NOD2 mutations (Odds Ratio, O.R. 10.1), a smoking history (O.R. 2.25 per pack per day at diagnosis) or a younger age at diagnosis (O.R. 0.97 per each increased year). Presence of ileal disease (O.R. 4.8) and carrying one or two NOD2 mutations (O.R. 1.9 and 3.5, respectively) were independent risk factors for stricturing or non-perianal fistulizing behavior. Ileal disease, youthful onset and smoking at diagnosis (but not NOD2 mutations) were risk factors for early surgery.

CONCLUSIONS

Carrying two NOD2 mutations predicts youthful onset, ileal disease involvement, and development of stricturing or non-perianal fistulizing complications. Smoking and early onset independently influence ileal site and time to surgery.

Tobacco consumption and disease duration are associated with fistulizing and stricturing behaviors in the first 8 years of Crohn's disease

OBJECTIVES

Crohn's disease (CD) can be classified by site of involvement and by clinical behavior. Claims for stability of behavior are based on patients who have had surgery, usually within 8 yr of diagnosis. Disease during this period may begin as inflammatory and may evolve into stricturing or fistulizing behavior. Our aim was to determine the influence of genetic and environmental factors on the prevalence of inflammatory behavior among patients who have had CD for <8 yr.

METHODS

Disease type (inflammatory, stricturing, or fistulizing), site, and duration were determined in 311 consecutive patients with CD. The analysis was then restricted to those with a disease duration of <8 yr, and influences on the prevalence of inflammatory type disease were compared with those of the complicated type (fistulizing and stricturing), including disease site, family history, Jewish ethnicity, and pack-years of cigarette smoking after diagnosis were determined through univariate and multivariate analyses.

RESULTS

The prevalence of inflammatory type disease was 0.63 and 0.3 (p < 0.0001) in patients with a disease duration of <8 yr and > or =8 yr, respectively. Multivariate analysis revealed a 91% decrease in the odds of inflammatory disease among those with > or =1 pack-year of smoking after diagnosis among individuals with disease <8 yr. This was not influenced by disease location, family history of inflammatory bowel disease (IBD), or Jewish ethnicity.

CONCLUSIONS

The prevalence of inflammatory CD decreased with time. Tobacco consumption was associated with this decline during the early phase of disease, suggesting that tobacco may influence the progression of inflammatory to stricturing or fistulizing type disease.

Tobacco consumption and disease duration are associated with fistulizing and stricturing behaviors in the first 8 years of Crohn's disease

OBJECTIVES

Crohn's disease (CD) can be classified by site of involvement and by clinical behavior. Claims for stability of behavior are based on patients who have had surgery, usually within 8 yr of diagnosis. Disease during this period may begin as inflammatory and may evolve into stricturing or fistulizing behavior. Our aim was to determine the influence of genetic and environmental factors on the prevalence of inflammatory behavior among patients who have had CD for <8 yr.

METHODS

Disease type (inflammatory, stricturing, or fistulizing), site, and duration were determined in 311 consecutive patients with CD. The analysis was then restricted to those with a disease duration of <8 yr, and influences on the prevalence of inflammatory type disease were compared with those of the complicated type (fistulizing and stricturing), including disease site, family history, Jewish ethnicity, and pack-years of cigarette smoking after diagnosis were determined through univariate and multivariate analyses.

RESULTS

The prevalence of inflammatory type disease was 0.63 and 0.3 (p < 0.0001) in patients with a disease duration of <8 yr and > or =8 yr, respectively. Multivariate analysis revealed a 91% decrease in the odds of inflammatory disease among those with > or =1 pack-year of smoking after diagnosis among individuals with disease <8 yr. This was not influenced by disease location, family history of inflammatory bowel disease (IBD), or Jewish ethnicity.

CONCLUSIONS

The prevalence of inflammatory CD decreased with time. Tobacco consumption was associated with this decline during the early phase of disease, suggesting that tobacco may influence the progression of inflammatory to stricturing or fistulizing type disease.

Colonoscopy in octogenarians: a prospective outpatient study

OBJECTIVES

The number of octogenarians (age > or =80 yr) referred for colonoscopy is increasing. Reported success rates regarding colonoscopy completion and adequacy of colonic preparation are poor overall in this group. This may be the result of age-related differences or biases due to retrospective data. The aims of this study were to prospectively determine differences between octogenarians and nonoctogenarians in adequacy of colonic preparation, success in completing colonoscopy, and complications of conscious sedation.

METHODS

Prospective cohort study of 250 consecutive outpatients (150 nonoctogenarians and 100 octogenarians) referred for colonoscopy. Colonic preparation tolerance was assessed before colonoscopy, and the success rate and preparation were evaluated after the procedure. Conscious sedation complications were compared.

RESULTS

In octogenarians and nonoctogenarians preparation tolerance (86% and 90%, respectively) was similar. Endoscopic success rate was slightly lower in octogenarians (90% vs 99%, p = 0.002). Preparation was poor in 16% of octogenarians compared with 4% of nonoctogenarians (p = 0.001). This was independent of the type of preparation used. Oxygen desaturation was more common in octogenarians (27% vs 19%, p = 0.0007) and associated with a higher meperidine dose (1.05 vs 0.75 mg/kg). No adverse outcomes occurred in either study group.

CONCLUSIONS

Colonic preparations were well tolerated and colonoscopic success rates were high in octogenarians and nonoctogenarians. However, poor colonic preparation was four times as likely in octogenarians and was the most important impediment to adequate colonoscopy.

Enteral versus parenteral nutrition: the patient's preference

BACKGROUND

Given that, in most clinical circumstances, enteral nutrition (nasal gastric tube feeding) may not necessarily be superior to parenteral nutrition (IV feeding), consideration of patient preference should be included in decisions on the method of feeding.

OBJECTIVES

To evaluate patient preference for nasal gastric versus IV feeding.

METHODS

We administered a written questionnaire to 101 hospitalized oncology patients and 98 outpatients without gastrointestinal illness (controls). Statistical analyses included comparisons of group means with Student t tests, comparisons of proportions with chi2 tests, and logistic regression analysis.

RESULTS

Demographic variables of the 2 groups were comparable. In both groups, most individuals preferred IV to tube feeding. Preference for IV or tube feeding was related to patient perception of the comfort of these interventions. In logistic regression analyses, the strongest influences on preference were age and perceived comfort of IV feeding. Older individuals preferred IV to tube feeding. Gender, education level, physician's recommendation, and cost did not influence patient preference.

CONCLUSIONS

Most patients prefer IV to nasal gastric feeding. Awareness of this patient preference is helpful in making decisions regarding the method of nutrient delivery.

Methodologic pitfalls in the determination of genetic anticipation: the case of Crohn disease

BACKGROUND

The term genetic anticipation is used when genetically transmitted disease manifests at increasingly younger ages with each succeeding generation: that is, if the offspring of patients develop the disease, they will tend to do so at an earlier age than their parents. In some monogenetic disorders, genetic anticipation has a biological basis in expanded genetic triplet repeats; however, some have claimed that it occurs in polygenic disorders, such as Crohn disease, in which its mechanism cannot be explained.

OBJECTIVE

To show how apparent changes in age at diagnosis of Crohn disease between generations, which could suggest genetic anticipation, can be an artifact of inadequate analysis based on age at diagnosis in cohorts that have not been followed for a sufficiently long time.

DESIGN

Comparison of ages at diagnosis of Crohn disease among different birth cohorts, before and after adjustment for observation time.

SETTING

Meyerhoff Center for Inflammatory Bowel Disease, Johns Hopkins Hospital, Baltimore, Maryland.

PATIENTS

928 consecutive outpatients with Crohn disease.

MEASUREMENTS

Trends in age at diagnosis of Crohn disease among birth cohorts were determined by calculating Pearson correlation coefficients and performing Kaplan-Meyer analysis before and after adjustment for observation time. Adjustment for observation time was performed by ensuring that the time during which all included patients were at risk for Crohn disease was equal and that all patients had developed disease by the end of the risk period.

RESULTS

Mean age at diagnosis decreased by approximately 5 years with each subsequent 10-year birth cohort on the basis of crude cross-sectional data that could suggest genetic anticipation between generations. However, after adjustment for observation time, the age at diagnosis decreased minimally, if at all, with each successive generation.

CONCLUSIONS

Apparent genetic anticipation can be explained by observational biases without invoking any additional genetic influences. Claims for genetic anticipation must be based on methods that properly account for the duration of observation in all persons being studied.