Artificial intelligence fails to improve colonoscopy quality: A single centre retrospective cohort study

BACKGROUND

Limited data currently exists on the clinical utility of Artificial Intelligence Assisted Colonoscopy (AIAC) outside of clinical trials.

AIM

To evaluate the impact of AIAC on key markers of colonoscopy quality compared to conventional colonoscopy (CC).

METHODS

This single-centre retrospective observational cohort study included all patients undergoing colonoscopy at a secondary centre in Brisbane, Australia. CC outcomes between October 2021 and October 2022 were compared with AIAC outcomes after the introduction of the Olympus Endo-AID module from October 2022 to January 2023. Endoscopists who conducted over 50 procedures before and after AIAC introduction were included. Procedures for surveillance of inflammatory bowel disease were excluded. Patient demographics, proceduralist specialisation, indication for colonoscopy, and colonoscopy quality metrics were collected. Adenoma detection rate (ADR) and sessile serrated lesion detection rate (SSLDR) were calculated for both AIAC and CC.

RESULTS

The study included 746 AIAC procedures and 2162 CC procedures performed by seven endoscopists. Baseline patient demographics were similar, with median age of 60 years with a slight female predominance (52.1%). Procedure indications, bowel preparation quality, and caecal intubation rates were comparable between groups. AIAC had a slightly longer withdrawal time compared to CC, but the difference was not statistically significant. The introduction of AIAC did not significantly change ADR (52.1% for AIAC vs 52.6% for CC, P = 0.91) or SSLDR (17.4% for AIAC vs 18.1% for CC, P = 0.44).

CONCLUSION

The implementation of AIAC failed to improve key markers of colonoscopy quality, including ADR, SSLDR and withdrawal time. Further research is required to assess the utility and cost-efficiency of AIAC for high performing endoscopists.

An Extremes of Phenotype Approach Confirms Significant Genetic Heterogeneity in Patients with Ulcerative Colitis

BACKGROUND AND AIMS

Ulcerative colitis [UC] is a major form of inflammatory bowel disease globally. Phenotypic heterogeneity is defined by several variables including age of onset and disease extent. The genetics of disease severity remains poorly understood. To further investigate this, we performed a genome wide association [GWA] study using an extremes of phenotype strategy.

METHODS

We conducted GWA analyses in 311 patients with medically refractory UC [MRUC], 287 with non-medically refractory UC [non-MRUC] and 583 controls. Odds ratios [ORs] were calculated for known risk variants comparing MRUC and non-MRUC, and controls.

RESULTS

MRUC-control analysis had the greatest yield of genome-wide significant single nucleotide polymorphisms [SNPs] [2018], including lead SNP = rs111838972 [OR = 1.82, p = 6.28 × 10-9] near MMEL1 and a locus in the human leukocyte antigen [HLA] region [lead SNP = rs144717024, OR = 12.23, p = 1.7 × 10-19]. ORs for the lead SNPs were significantly higher in MRUC compared to non-MRUC [p < 9.0 × 10-6]. No SNPs reached significance in the non-MRUC-control analysis (top SNP, rs7680780 [OR 2.70, p = 5.56 × 10-8). We replicate findings for rs4151651 in the Complement Factor B [CFB] gene and demonstrate significant changes in CFB gene expression in active UC. Detailed HLA analyses support the strong associations with MHC II genes, particularly HLA-DQA1, HLA-DQB1 and HLA-DRB1 in MRUC.

CONCLUSIONS

Our MRUC subgroup replicates multiple known UC risk variants in contrast to non-MRUC and demonstrates significant differences in effect sizes compared to those published. Non-MRUC cases demonstrate lower ORs similar to those published. Additional risk and prognostic loci may be identified by targeted recruitment of individuals with severe disease.

A Method Using Longitudinal Laboratory Data to Predict Future Intestinal Complication in Patients with Crohn's Disease

BACKGROUND

Stenosis, fistulization, and perforation of the bowel are severe outcomes which can occur in patients with Crohn's disease. Accurate prediction of these events may enable clinicians to alter treatment strategies and avoid these outcomes.

AIMS

To study the correlation between longitudinal laboratory testing and subsequent intestinal complications in patients with Crohn's disease.

METHODS

An observational cohort of patients with Crohn's disease at a single center were analyzed between 01/01/1994 and 06/30/2016. A complication was defined as the development of an intestinal fistula, stenosis, or perforation. Exploratory analysis using Cox regression was performed to select the best statistical method to represent longitudinal laboratory data. Cox regression was used to identify laboratory variables independently associated with the development of a subsequent complication. A clinical scoring tool was designed.

RESULTS

In 246 patients observed over a median of 5.72 years, 134 complications occurred. Minimum or maximum value in a preceding window period of one year was most strongly associated with subsequent complication. A Longitudinal Laboratory score of ≥ 2 (maximum albumin level < 39 g/L = 1, maximum mean cell volume < 88 fL = 1, minimum platelet count > 355 × 10⁹/L = 1, minimum C reactive protein > 5 mg/L = 1) was 62% sensitive and 91% specific in identifying patients who develop a subsequent complication.

CONCLUSION

A consistent reduction in serum albumin and mean cell volume, and a consistent increase in platelet count and C reactive protein were associated with a subsequent complication in patients with Crohn's disease. Longitudinal laboratory tests may be used as described in this paper to provide a rational for earlier escalation of therapy.

Ileal Pouch-Anal Anastomosis for Ulcerative Colitis: An Australian Institution's Experience

PURPOSE

We report outcomes and evaluate patient factors and the impact of surgical evolution on outcomes in consecutive ulcerative colitis patients who had restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) at an Australian institution over 26 years.

METHODS

Data including clinical characteristics, preoperative medical therapy, and surgical outcomes were collected. We divided eligible patients into 3 period arms (period 1, 1990 to 1999; period 2, 2000 to 2009; period 3, 2010 to 2016). Outcomes of interest were IPAA leak and pouch failure.

RESULTS

A total of 212 patients were included. Median follow-up was 50 (interquartile range, 17 to 120) months. Rates of early and late complications were 34.9% and 52.0%, respectively. Early complications included wound infection (9.4%), pelvic sepsis (8.0%), and small bowel obstruction (6.6%) while late complications included small bowel obstruction (18.9%), anal stenosis (16.8%), and pouch fistula (13.3%). Overall, IPAA leak rate was 6.1% and pouch failure rate was 4.8%. Eighty-three patients (42.3%) experienced pouchitis. Over time, we observed an increase in patient exposure to thiopurine (P=0.0025), cyclosporin (P=0.0002), and anti-tumor necrosis factor (P<0.00001) coupled with a shift to laparoscopic technique (P<0.00001), stapled IPAA (P<0.00001), J pouch configuration (P<0.00001), a modified 2-stage procedure (P=0.00012), and a decline in defunctioning ileostomy rate at time of IPAA (P=0.00002). Apart from pouchitis, there was no significant difference in surgical and chronic inflammatory pouch outcomes with time.

CONCLUSION

Despite greater patient exposure to immunomodulatory and biologic therapy before surgery coupled with a significant change in surgical techniques, surgical and chronic inflammatory pouch outcome rates have remained stable.

Level of UV Exposure, Skin Type, and Age Are More Important than Thiopurine Use for Keratinocyte Carcinoma Development in IBD Patients

BACKGROUND

Retrospective studies observe an increased risk of keratinocyte carcinomas (KCs) in patients with inflammatory bowel disease (IBD) on thiopurine (TP) medication. The role of traditional risk factors such as skin type and sun protection behavior has not been studied in this population. This study aimed to examine traditional KC risk factors and thiopurine use on skin cancer development in an IBD cohort.

METHODS

Consecutive IBD patients were recruited from four specialist centers in Australia and New Zealand, each with varying UV exposure indices. Data pertaining to race, skin color, freckling and sun protection behavior, dose of TP therapy, and skin cancer development were elicited through a self-reported questionnaire.

RESULTS

A total of 691 IBD patients were included with 62 reporting KC development. Thiopurine usage was similar among patients who developed skin cancer compared with those who did not (92% vs. 89%, p = 0.3). There was no statistically significant association between KC development and TP dose or 6-thioguanine nucleotide levels. In multivariate modeling, four factors were independently and significantly associated with KC: age over 61 years old versus less than 30 years old (OR 6.76; 95% CI 2.38-19.18), residing in Brisbane versus Christchurch (OR 3.3; 95% CI 1.6-6.8), never staying in the shade versus staying in the shade ≥ 50% of the time (OR 3.8; 95% CI 1.4-10.5), and having a skin type that never tanned versus other skin types (OR 6.9; 95% CI 2.9-16.0).

CONCLUSION

Skin type, age, and sun protection behavior are more important risk factors for KC development than thiopurine medication use in this IBD population.

A validated risk stratification tool for detecting high-risk small bowel Crohn's disease

BACKGROUND

Delays in Crohn's disease (CD) diagnosis are positively associated with ileal location and an increased risk of complications.

AIM

To develop a simple risk assessment tool to enable primary care physicians to recognise potential ileal CD earlier, shortening the delay to specialist investigation METHODS: Three cohorts were acquired for this study. Cohort 1 included 61 patients retrospectively identified with ileal CD between 2000 and 2010 and 78 matched controls drawn from a cohort referred for investigation of abdominal symptoms. Cohort 2 included 42 individuals diagnosed with ileal CD and 57 controls identified prospectively. Cohort 3 included an additional 84 individuals with ileal CD and 495 without CD referred for colonoscopy. Clinical symptoms and serological biomarkers were acquired and used to develop a risk prediction algorithm. The algorithm was trained independently on each of the three cohorts and tested on the latter two cohorts.

RESULTS

Altered bowel habit with abdominal pain combined with derangements in white cell count (WCC), albumin and platelet counts were important features in predicting ileal CD (AUC = 0.92, 95% CI = 0.89-0.92). This was validated in cohorts 2 (AUC = 0.96, 95% CI = 0.95-0.98) and 3 (AUC = 0.94, 95% CI = 0.92-0.96). C-reactive protein was independently associated with ileal CD but non-signficant in a multivariate model.

CONCLUSION

A web-based risk stratification tool for ileal CD has been developed from objective and symptom-based criteria. This tool enables primary care physicians to more confidently request urgent specialist assessment for patients identified as at high risk for ileal CD.

Short-term colectomy is avoided in over half of regional patients failing medical therapy for acute severe ulcerative colitis with co-ordinated transfer and tertiary care

BACKGROUND AND AIMS

Many patients presenting with an acute severe ulcerative colitis to a regional hospital are transferred to a metropolitan hospital for specialised care. This study aimed to evaluate the outcomes and characteristics of these patients.

METHOD

A retrospective observational cohort study was conducted to examine the 30-day colectomy rate using prospectively collected data on 69 consecutive index cases of acute severe ulcerative colitis transferred from regional hospitals to our metropolitan hospital meeting Truelove and Witts criteria. Those that avoided colectomy were followed out to 1 year to examine outcomes.

RESULTS

The 30-day colectomy rate was 46.4% (32/69) in regional transfer patients. Rescue therapy was administered to 65% (45/69) of patients after transfer to our metropolitan hospital. Colectomy was avoided in 55% of these patients at 30 days. Colectomy free status was maintained in 78% (29/39) of these patients. Mortality was 0% at 30 days and 1 year.

CONCLUSION

Over 50% of the patients failing therapy in a regional centre and requiring transfer avoided short term colectomy with co-ordinated referral for rescue therapy in a tertiary metropolitan inflammatory bowel disease unit. These patients would have ultimately required colectomy in their regional hospital without intervention.

The effect of pre-admission immunosuppression on colectomy rates in acute severe ulcerative colitis

BACKGROUND

Patients on immunosuppression at the time of acute severe ulcerative colitis have been suggested to be at a higher risk of colectomy than those who are treatment-naïve. The aim of this study was to examine the effect of immunosuppressive therapy on the risk of colectomy.

METHOD

We conducted a retrospective observational cohort study using prospective data examining the 30 day and 1 year colectomy rates of 200 consecutive patients with an index episode of acute severe ulcerative colitis as defined by the Truelove and Witts criteria.

RESULTS

Immunosuppression on admission was shown not to increase colectomy rate at 30 days post-admission (immunomodulator: p = 0.422, oral steroids: p = 0.555). A total of 24 patients underwent colectomy between 30 days and 1 year. A three-fold higher risk of colectomy at 1 year was seen in those requiring an immunomodulator prior to the index admission compared with those started de novo during the index admission [41% versus 14% odds ratio (OR): 2.93 (1.19-7.24 p = 0.016)]. Factors most predictive of colectomy at 30 days were abdominal radiographic colonic dilation ⩾5.5 cm, first presentation of ulcerative colitis, C-reactive protein ⩾ 45 mg/l on day 3 of therapy and bowel frequency ⩾8 on day 3.

CONCLUSION

The need for an immunomodulator prior to admission with acute severe ulcerative colitis increases the medium-term colectomy rate by three-fold at 1 year. Prospective studies are needed to confirm these findings and develop strategies to reduce the high risk in this subgroup of patients.

Development and evaluation of a risk assessment tool to improve clinical triage accuracy for colonoscopic investigations

Background

Gastroenterology Departments at hospitals within Australia receive thousands of General Practitioner (GP)-referral letters for gastrointestinal investigations every month. Many of these requests are for colonoscopy. This study aims to evaluate the performance of the current symptoms-based triage system compared to a novel risk score using objective markers.

Methods

Patients with lower abdominal symptoms referred by their GPs and triaged by a Gastroenterology consultant to a colonoscopy consent clinic were recruited into the study. A risk assessment tool (RAT) was developed using objective data (clinical, demographic, pathology (stool test, FIT), standard blood tests and colonoscopy outcome). Colonoscopy and histology results were scored and then stratified as either significant bowel disease (SBD) or non-significant bowel disease (non-SBD).

Results

Of the 467 patients in our study, 45.1% were male, the mean age was 54.3 ± 13.8 years and mean BMI was 27.8 ± 6.2. Overall, 26% had SBD compared to 74% with non-SBD (42% of the cohort had a normal colonoscopy). Increasing severity of referral symptoms was related to a higher triage category, (rectal bleeding, P = 2.86*10^-9; diarrhoea, P = 0.026; abdominal pain, P = 5.67*10^-4). However, there was no significant difference in the prevalence of rectal bleeding (P = 0.991) or diarrhoea (P = 0.843) for SBD. Abdominal pain significantly reduced the risk of SBD (P = 0.0344, OR = 0.52, CI = 0.27-0.95). Conversely, the RAT had a very high specificity of 98% with PPV and NPV of SBD prediction, 74% and 77%, respectively. The RAT provided an odds ratio (OR) of 9.0, 95%CI 4.29-18.75, p = 2.32*10^-11), higher than the FIT test (OR = 5.3, 95%CI 2.44-11.69, p = 4.88*10^-6), blood score (OR = 2.8, 95%CI 1.72- 4.38, p = 1.47*10^-5) or age (OR = 2.5, 95%CI 1.61-4.00, 5.12*10^-5) independently. Notably, the ORs of these individual objective measures were higher than the current practice of symptoms-based triaging (OR = 1.4, 95%CI 0.88-2.11, p = 0.153).

Conclusions

It is critical that individuals with high risk of having SBD are triaged to the appropriate category with the shortest wait time. Here we provide evidence that a combination of blood markers, demographic markers and the FIT test have a higher diagnostic accuracy for SBD than FIT alone.

A Method to Exploit the Structure of Genetic Ancestry Space to Enhance Case-Control Studies

One goal of human genetics is to understand the genetic basis of disease, a challenge for diseases of complex inheritance because risk alleles are few relative to the vast set of benign variants. Risk variants are often sought by association studies in which allele frequencies in case subjects are contrasted with those from population-based samples used as control subjects. In an ideal world we would know population-level allele frequencies, releasing researchers to focus on case subjects. We argue this ideal is possible, at least theoretically, and we outline a path to achieving it in reality. If such a resource were to exist, it would yield ample savings and would facilitate the effective use of data repositories by removing administrative and technical barriers. We call this concept the Universal Control Repository Network (UNICORN), a means to perform association analyses without necessitating direct access to individual-level control data. Our approach to UNICORN uses existing genetic resources and various statistical tools to analyze these data, including hierarchical clustering with spectral analysis of ancestry; and empirical Bayesian analysis along with Gaussian spatial processes to estimate ancestry-specific allele frequencies. We demonstrate our approach using tens of thousands of control subjects from studies of Crohn disease, showing how it controls false positives, provides power similar to that achieved when all control data are directly accessible, and enhances power when control data are limiting or even imperfectly matched ancestrally. These results highlight how UNICORN can enable reliable, powerful, and convenient genetic association analyses without access to the individual-level data.

Crohn's disease and smoking: is it ever too late to quit?

BACKGROUND

Smoking increases CD risk. The aim was to determine if smoking cessation at, prior to, or following, CD diagnosis affects medication use, disease phenotypic progression and/or surgery.

METHODS

Data on CD patients with disease for ≥5 yrs were collected retrospectively including the Montreal classification, smoking history, CD-related abdominal surgeries, family history, medication use and disease behaviour at diagnosis and the time when the disease behaviour changed.

RESULTS

1115 patients were included across six sites (mean follow-up-16.6 yrs). More non-smokers were male (p=0.047) with A1 (p<0.0001), L4 (p=0.028) and perianal (p=0.03) disease. Non-smokers more frequently received anti-TNF agents (p=0.049). (p=0.017: OR 2.5 95%CI 1.18-5.16) and those who ceased smoking prior to diagnosis (p=0.045: OR 2.3 95%CI 1.02-5.21) progressed to complicated (B2/B3) disease as compared to those quitting at diagnosis. Patients with uncomplicated terminal ileal disease at diagnosis more frequently developed B2/B3 disease than isolated colonic CD (p<0.0001). B2/B3 disease was more frequent with perianal disease (p<0.0001) and if i.v. steroids (p=0.004) or immunosuppressants (p<0.0001) were used. 49.3% (558/1115) of patients required at least one intestinal surgery. More smokers had a 2nd surgical resection than patients who quit at, or before, the 1st resection and non-smokers (p=0.044: HR=1.39 95%CI 1.01-1.91). Patients smoking >3 cigarettes/day had an increased risk of developing B2/B3 disease (p=0.012: OR 3.8 95%CI 1.27-11.17).

CONCLUSION

Progression to B2/B3 disease and surgery is reduced by smoking cessation. All CD patients regardless of when they were diagnosed, or how many surgeries, should be strongly encouraged to cease smoking.