During the twentieth century, inflammatory bowel disease (IBD) was considered a disease of early industrialized regions in North America, Europe and Oceania¹. At the turn of the twenty-first century, IBD incidence increased in newly industrialized and emerging regions in Africa, Asia and Latin America, while the prevalence in early industrialized regions continued to grow steadily^2,3,4. Changes in the incidence and prevalence denote the evolution of IBD across four epidemiologic stages: stage 1 (emergence), characterized by low incidence and prevalence; stage 2 (acceleration in incidence), marked by rapidly rising incidence and low prevalence; and stage 3 (compounding prevalence), where the incidence decelerates, plateaus or declines while the prevalence steadily increases. A fourth stage (prevalence equilibrium) has been proposed in which the prevalence slope plateaus due to demographic shifts in an ageing IBD population, but it has not yet been evidenced. To date, these stages have remained theoretical, lacking specific numerical indicators to define transition points. Here, using real-world data from 522 population-based studies encompassing 82 global regions and spanning more than a century (1920–2024), we show spatiotemporal transitions across stages 1–3 and model stage 4 progression. Understanding the evolution of IBD across epidemiologic stages enables healthcare systems to better anticipate the future worldwide burden of IBD.

Introduction: Few recent data on the epidemiology of inflammatory bowel disease (IBD) are available, especially in Southern Europe. Aim: To evaluate the prevalence, incidence and mortality of IBD in Catalonia during the period 2011–2016. Material and methods: Data on the prevalence, incidence and mortality of IBD were obtained from the Catalan Health Surveillance System (CHSS). Crude incidence and prevalence rates were calculated for all the Catalan population. Trends in age-sex-adjusted rates were also estimated, and logistic regression was used to calculate the adjusted mortality odds ratio (OR). Data for Crohn’s disease (CD) and ulcerative colitis (UC) were analyzed separately. Results: The prevalence per 100,000 inhabitants in 2016 was 353.9 for UC and 191.4 for CD. The total number of IBD patients rose from 29543 in 2011 to 40614 in 2016. IBD was associated with significantly elevated adjusted mortality ratios: 1.28 (95% CI: 1.6–1.4) for UC and 1.85 (95% CI: 1.62–2.12) for CD. Conclusions: IBD prevalence is very high and is increasing rapidly in Catalonia. Both CD and UC are associated with significantly higher mortality rates.

Background and Aims: Switching from intravenous infliximab (IV-IFX) to subcutaneous biosimilar infliximab (SC-IFX) has been shown to safely maintain clinical remission and increase drug levels in patients with Crohn’s disease (CD) and ulcerative colitis (UC). The aim of this study was to evaluate long-term outcomes after switching from IV-IFX to SC-IFX, including the drug concentration thresholds for maintaining remission and other predictors for loss of response after the switch. Methods: This multicenter observational study involved CD and UC patients who were in clinical remission for at least 24 weeks and were scheduled to switch from IV-IFX to SC-IFX. Results: Two hundred and twenty patients were included (74 UC [34%] and 146 CD [66%]). IV-IFX was administered for 52.5 months (range 25-89). Before switch, 106 (49%) patients were receiving intensified IV-IFX. While SC-IFX levels significantly increased following the switch from IV-IFX to SC-IFX, clinical parameters, C-reactive protein, and fecal calprotectin remained unchanged during follow-up. SC-IFX levels were significantly higher in patients receiving the standard IV-IFX dose than in those receiving the intensified dose. Immunomodulatory therapy at baseline and perianal disease had no effect on IFX trough levels, whereas higher body mass index was associated with increased levels. The suggested optimal SC-IFX cutoff concentration for clinical and biochemical remissions based on receiver operating characteristic analysis was 12.2 μg/mL (area under the curve [AUC]: 0.62) at Week 12 and 13.2 μg/mL (AUC: 0.57) at Week 52. Drug persistence was 92% at Week 52, with a good safety profile. Conclusions: Switching from IV-IFX to SC-IFX safely maintains long-term remission in patients with CD and UC. In maintenance, the optimal cutoff point associated with remission was 12-13 μg/mL.

Current medical treatment for inflammatory bowel disease (IBD) does not achieve 100% response rates, and a subset of refractory and severely ill patients have persistent active disease after being treated with all possible drug alternatives. The combination of two biological therapies (CoT) seems a reasonable alternative, and has been increasingly tested in very difficult cases. The present review suggests that CoT seems to be safe and effective for refractory and severely ill IBD patients. Ustekinumab plus vedolizumab and vedolizumab plus anti-TNF were the most used CoTs for Crohn’s disease. For ulcerative colitis, the most used CoTs were vedolizumab plus anti-TNF and vedolizumab plus tofacitinib. The aforesaid CoTs have shown good efficacy and few adverse events have been reported.