A review on statistical and machine learning competing risks methods.

When modeling competing risks (CR) survival data, several techniques have been proposed in both the statistical and machine learning literature. State-of-the-art methods have extended classical approaches with more flexible assumptions that can improve predictive performance, allow high-dimensional data and missing values, among others. Despite this, modern approaches have not been widely employed in applied settings. This article aims to aid the uptake of such methods by providing a condensed compendium of CR survival methods with a unified notation and interpretation across approaches. We highlight available software and, when possible, demonstrate their usage via reproducible R vignettes. Moreover, we discuss two major concerns that can affect benchmark studies in this context: the choice of performance metrics and reproducibility.

Longitudinal Fecal Calprotectin Profiles Characterize Disease Course Heterogeneity in Crohn's Disease.

BACKGROUND AND AIMS: The progressive nature of Crohn's disease is highly variable and hard to predict. In addition, symptoms correlate poorly with mucosal inflammation. There is therefore an urgent need to better characterize the heterogeneity of disease trajectories in Crohn's disease by utilizing objective markers of inflammation. We aimed to better understand this heterogeneity by clustering Crohn's disease patients with similar longitudinal fecal calprotectin profiles. METHODS: We performed a retrospective cohort study at the Edinburgh IBD Unit, a tertiary referral center, and used latent class mixed models to cluster Crohn's disease subjects using fecal calprotectin observed within 5 years of diagnosis. Information criteria, alluvial plots, and cluster trajectories were used to decide the optimal number of clusters. Chi-square test, Fisher's exact test, and analysis of variance were used to test for associations with variables commonly assessed at diagnosis. RESULTS: Our study cohort comprised 356 patients with newly diagnosed Crohn's disease and 2856 fecal calprotectin measurements taken within 5 years of diagnosis (median 7 per subject). Four distinct clusters were identified by characteristic calprotectin profiles: a cluster with consistently high fecal calprotectin and 3 clusters characterized by different downward longitudinal trends. Cluster membership was significantly associated with smoking (P = .015), upper gastrointestinal involvement (P < .001), and early biologic therapy (P < .001). CONCLUSIONS: Our analysis demonstrates a novel approach to characterizing the heterogeneity of Crohn's disease by using fecal calprotectin. The group profiles do not simply reflect different treatment regimens and do not mirror classical disease progression endpoints.

Real-world effectiveness of upadacitinib in Crohn's disease: a UK multicentre retrospective cohort study.

Background: Upadacitinib is a Janus kinase inhibitor, which has recently been approved for treating Crohn's disease. There are limited real-world studies on the outcomes of upadacitinib in Crohn's disease. Objective: Our aim was to evaluate the outcomes of upadacitinib in a real-world Crohn's disease cohort. Methods: We conducted a retrospective, multicentre, cohort study over a 2-year period across National Health Service (NHS) Lothian and Royal Devon University Healthcare NHS Foundation Trust. The primary outcome was treatment persistence at week 24. Secondary endpoints were corticosteroid-free clinical remission (Harvey-Bradshaw Index (HBI)<5) and biomarker remission (C-reactive protein (CRP)≤5 mg/L and faecal calprotectin (FCAL)<250 µg/g) at 12, 24 and 52 weeks. We recorded adverse events. Results: 135 patients commenced upadacitinib as of the 1 January 2024, of which 93 patients with active Crohn's disease were included with a minimum of 12 weeks follow-up. The median follow-up time was 25 weeks (IQR 15-42 weeks). 82% of the cohort had exposure to at least two classes of advanced therapies, and 52% had exposure to at least three classes of advanced therapies. Treatment persistence was 87.1% at week 12, 81.7% at week 24 and 62.8% at week 52. Rates of clinical remission were 64% (42/66), 48% (22/46) and 38% (8/21) at weeks 12, 24 and 52, respectively. Significant reductions in HBI, CRP and FCAL were observed during follow-up. 14% (13/91) had a hospitalisation due to Crohn's disease. Adverse events occurred in 40% (37/93) of the cohort, of which 12% (11/93) were serious. Conclusion: Upadacitinib was effective in a real-world, highly refractory, Crohn's disease cohort with good persistence.

Long-term outcomes and predictors of vedolizumab persistence in ulcerative colitis.

Background: Long-term vedolizumab (VDZ) outcomes in real-world cohorts have been largely limited to 1-year follow-up, with few bio-naïve patients or objective markers of inflammation assessed. Objectives: We aimed to assess factors affecting VDZ persistence including clinical, biochemical and faecal biomarker remission at 1, 3 and 5 years. Design: We performed a retrospective, observational, cohort study. Methods: All adult inflammatory bowel disease (IBD) patients who had received VDZ induction for ulcerative colitis (UC)/IBD-unclassified (IBDU) were included. Baseline phenotype and follow-up data were collected via a review of electronic medical records. Results: We included 290 patients [UC n = 271 (93.4%), IBDU n = 19 (6.6%)] with a median time on VDZ of 27.6 months (interquartile range: 14.4-43.2). At the end of follow-up, a total of 157/290 (54.1%) patients remained on VDZ. The median time to discontinuation was 14.1 months (7.0-23.3). Previous exposure to ⩾1 advanced therapy, steroid use at baseline and disease extension (E3 and E2 versus E1) were independent predictors for worse VDZ persistence. Clinical remission (partial Mayo < 2) was 75.7% (171/226), 72.4% (157/217) and 70.2% (127/181) at years 1, 3 and 5, respectively. Steroid use during maintenance VDZ therapy occurred in 31.7% (92/290), hospitalization in 15.5% (45/290) and surgery in 3.4% (10/291). The rate of serious adverse events was 1.2 per 100 patient-years of follow-up. Conclusion: VDZ effectiveness appears enduring with favourable long-term safety profile. VDZ persistence was influenced by previous exposure to biologics/small molecules, disease distribution and steroid use at baseline in our study.

Vedolizumab long-term use in ulcerative colitis What was this study done? • Vedolizumab efficacy and safety in ulcerative colitis have been firmly established by existing evidence. • Long-term data from the GEMINI trial further corroborate the favourable safety profile over an extended duration but there is little data on long-term vedolizumab use over 1 year. What did the researches do? • We performed a retrospective, observational, cohort study. All adult IBD patients who ever received vedolizumab induction from November 2014 to December 2021 for ulcerative colitis/IBDU were included. What did the researchers find? • This real-world study demonstrates that vedolizumab persistence exceeds 80% at 1 year and remains nearly 50% at 5 years with no new safety signals. • Worse vedolizumab persistence is associated with prior exposure to biologics/small molecules, more extensive disease involvement and steroid use at vedolizumab initiation. What do the findings mean? • These findings have important implications for drug positioning and sequencing, as well as for optimizing outcomes when vedolizumab is utilized as first-line therapy. Furthermore, it also emphasizes the long-term safety profile.

Multiple infliximab biosimilar switches appear to be safe and effective in a real-world inflammatory bowel disease cohort.

BACKGROUND: Switching from originator infliximab (IFX) to biosimilar IFX is effective and safe. However, data on multiple switching are scarce. The Edinburgh inflammatory bowel disease (IBD) unit has undertaken three switch programmes: (1) Remicade to CT-P13 (2016), (2) CT-P13 to SB2 (2020), and (3) SB2 to CT-P13 (2021). OBJECTIVE: The primary endpoint of this study was to assess CT-P13 persistence following switch from SB2. Secondary endpoints included persistence stratified by the number of biosimilar switches (single, double and triple), effectiveness and safety. METHODS: We performed a prospective, observational, cohort study. All adult IBD patients on IFX biosimilar SB2 underwent an elective switch to CT-P13. Patients were reviewed in a virtual biologic clinic with protocol driven collection of clinical disease activity, C-reactive protein (CRP), faecal calprotectin (FC), IFX trough/antibody levels, and drug survival. RESULTS: 297 patients (CD n = 196 [66%], ulcerative colitis/inflammatory bowel disease unclassified n = 101, [34%]) were switched (followed-up: 7.5 months [6.8-8.1]). This was the third, second and first IFX switch for 67/297 (22.5%), 138/297 (46.5%) and 92/297 (31%) of the cohort respectively. 90.6% of patients remained on IFX during follow-up. The number of switches was not independently associated with IFX persistence after adjusting for confounders. Clinical (p = 0.77), biochemical (CRP ≤5 mg/ml; p = 0.75) and faecal biomarker (FC<250 µg/g; p = 0.63) remission were comparable at baseline, week 12 and week 24. CONCLUSION: Multiple successive switches from IFX originator to biosimilars are effective and safe in patients with IBD, irrespective of the number of IFX switches.

Rates, predictive factors and effectiveness of ustekinumab intensification to 4- or 6-weekly intervals in Crohn's disease.

BACKGROUND: The UNITI trial reports efficacy of ustekinumab (UST) dose intensification in Crohn's disease (CD) from 12- to 8-weekly, but not 4-weekly. We aimed 1) to assess the cumulative incidence of UST dose intensification to 4- or 6-weekly, 2) to identify factors associated with dose intensification, and 3) to assess the effectiveness of this strategy. METHODS: We performed a retrospective, observational cohort study in NHS Lothian including all UST treated CD patients (2015-2020). RESULTS: 163 CD patients were treated with UST (median follow-up: 20.3 months [13.4-38.4]), of whom 55 (33.7%) underwent dose intensification to 4-weekly (n = 50, 30.7%) or 6-weekly (n = 5, 3.1%). After 1 year 29.9% were dose intensified. Prior exposure to both anti-TNF and vedolizumab (HR 9.5; 1.3-70.9), and concomitant steroid use at UST start (HR 1.8; 1.0-3.1) were associated with dose intensification. Following dose intensification, 62.6% patients (29/55) remained on UST beyond 1 year. Corticosteroid-free clinical remission was achieved in 27% at week 16 and 29.6% at last follow-up. CONCLUSION: One third of CD patients treated with UST underwent dose intensification to a 4- or 6-weekly interval within the first year. Patients who failed both anti-TNF and vedolizumab, or required steroids at initiation were more likely to dose intensify.

Real-World Cohort Study on the Effectiveness and Safety of Filgotinib Use in Ulcerative Colitis.

BACKGROUND: Filgotinib is a small molecule with preferential inhibition of Janus kinase type 1, approved for the treatment of ulcerative colitis in Scotland in May 2022. We present the first real world experience on its use in clinical practice. METHODS: In this retrospective, observational, cohort study we assessed patients with active ulcerative colitis who received filgotinib in NHS Lothian, Scotland. Baseline demographic, phenotype and follow-up data were collected via review of electronic medical records. RESULTS: We included 91 patients with median treatment duration of 39 weeks (IQR 23-49). Among the cohort, 67% (61/91) were biologic and small molecule naïve, whilst 20.9% (19/91) had failed one and 12.1% (11/91) ≥2 classes of advanced therapy. Of the biologic and small molecule naïve patients, 18% (11/61) were also thiopurine naïve. Clinical remission (partial Mayo score <2) was achieved in 71.9% (41/57) and 76.4% (42/55) of patients at weeks 12 and 24 respectively. Biochemical remission (CRP≤5mg/L) was achieved in 87.3% (62/71) at week 12 and 88.9% (40/45) at week 24. Faecal biomarker (calprotectin <250µg/g) remission was achieved in 82.8% (48/58) at week 12 and 79.5% (35/44) at week 24.At the end of follow-up, median 42 weeks (IQR 27-50), 82.4% (75/91) of patients remained on filgotinib. Severe adverse events leading to drug discontinuation occurred in 2.2% (2/91) and there were 8.8% (8/91) moderate adverse events that required temporary discontinuation. CONCLUSION: These are the first reported data on the real-world efficacy and safety of filgotinib in ulcerative colitis. Our findings demonstrate that filgotinib is an effective and low risk treatment option for these patients.

Patterns of emergency admission for IBD patients over the last 10 years in Lothian, Scotland: a retrospective prevalent cohort analysis.

OBJECTIVE: It is unclear how the compounding prevalence of inflammatory bowel disease (IBD) has translated into the causes and rates of hospitalisation, particularly in an era of increased biologic prescribing. We aimed to analyse these trends in a population-based IBD cohort over the last 10 years. DESIGN: The Lothian IBD registry is a complete, validated, prevalent database of IBD patients in NHS Lothian, Scotland. ICD-10 coding of hospital discharge letters from all IBD patient admissions to secondary care between 1 January 2010 and 31 December 2019 was interrogated for admission cause, with linkage to local/national data sets on death and prescribed drugs. RESULTS: Fifty-seven per cent (4673/8211) of all IBD patients were admitted to secondary care for >24 h between 1 January 2010 and 31 December 2019. In patients <40 years, IBD was the commonest reason for admission (38% of admissions), whereas infection was the most common cause in those >60 years (19% of admissions). Three per cent (243/8211) of IBD patients accounted for 50% of the total IBD bed-days over the study period. Age-standardised IBD admission rates fell from 39.4 to 25.5 admissions per 100,000 population between 2010 and 2019, an average annual percentage reduction of 3% (95% CI -4.5% to -2.1%, p < 0.0001). Non-IBD admission rates were unchanged overall (145-137 per 100,000 population) and specifically for serious (hospitalisation) and severe (ITU admission or death) infection over the same period. CONCLUSION: Despite compounding prevalence and increased biologic use, IBD admission rates are falling. The cause of admission varies with age, with infection the predominant cause in older patients.

Real-world experience with tofacitinib in ulcerative colitis: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Tofacitinib is a Janus kinase inhibitor (JAKi) recently approved for the treatment of moderate to severe ulcerative colitis (UC) based on robust efficacy and safety data derived from OCTAVE clinical trials. Evidence on the outcomes of tofacitinib therapy in real-world UC patients is needed, as a number of these patients would be deemed ineligible for clinical trials. We have therefore summarised data derived from observational, real-world evidence (RWE) studies on the effectiveness and safety of tofacitinib in moderate to severe UC patients. METHODS: We searched the PubMed, EMBASE, Scopus, Web of Science and Cochrane databases for observational studies on the use of tofacitinib in UC patients, published between 30 May 2018 and 24 January 2021. Pooled induction (8-14 weeks) and maintenance (16-26 weeks) clinical response and remission rates were calculated, as well as the proportion of reported adverse events using random effects models. RESULTS: Nine studies were included, comprising 830 patients, of which 81% were previously treated with anti-tumour necrosis factor (TNF) and 57% with vedolizumab. Induction of clinical response and remission were achieved in 51% (95% confidence interval, 41-60%) and 37% (26-45%) of patients, after a median follow-up of 8 weeks. At the end of a median follow-up of 24 weeks, maintenance of clinical response and remission were met in 40% (31-50%) and 29% (23-36%) of patients, respectively. Thirty-two percent of the patients had at least one adverse event, the most commonly reported being mild infection (13%) and worsening of UC, requiring colectomy (13%). A third of the patients (35%) discontinued tofacitinib, most frequently due to primary non-response (51%). CONCLUSION: Tofacitinib is a safe and effective therapy in real-world UC patients, as previously reported by clinical trials.

Effectiveness and Safety of Adalimumab Biosimilar SB5 in Inflammatory Bowel Disease: Outcomes in Originator to SB5 Switch, Double Biosimilar Switch and Bio-Naïve SB5 Observational Cohorts.

BACKGROUND AND AIMS: Multiple adalimumab [ADA] biosimilars are now approved for use in inflammatory bowel disease [IBD]; however, effectiveness and safety data remain scarce. We aimed to investigate long-term outcomes of the ADA biosimilar SB5 in IBD patients following a switch from the ADA originator [SB5-switch cohort] or after start of SB5 [SB5-start cohort]. METHODS: We performed an observational cohort study in a tertiary IBD referral centre. All IBD patients treated with Humira underwent an elective switch to SB5. We identified all these patients in a biological prescription database that prospectively registered all ADA start and stop dates including brand names. Data on IBD phenotype, C-reactive protein [CRP], drug persistence, ADA drug and antibody levels, and faecal calprotectin were collected. RESULTS: In total, 481 patients were treated with SB5, 256 in the SB5-switch cohort (median follow-up: 13.7 months [IQR 8.6-15.2]) and 225 in the SB5-start cohort [median follow-up: 8.3 months [4.2-12.8]). Of the SB5-switch cohort, 70.8% remained on SB5 beyond 1 year; 90/256 discontinued SB5, mainly due to adverse events [46/90] or secondary loss of response [37/90]. In the SB5-start cohort, 81/225 discontinued SB5, resulting in SB5-drug persistence of 60.3% beyond 1 year. No differences in clinical remission [p = 0.53], CRP [p = 0.80], faecal calprotectin [p = 0.40] and ADA trough levels [p = 0.55] were found between baseline, week 26 and week 52 following switch. Injection site pain was the most frequently reported adverse event. CONCLUSION: Switching from ADA originator to SB5 appeared effective and safe in this study with over 12 months of follow-up.