The Epidemiology of Inflammatory Bowel Diseases During the COVID-19 Pandemic: Comparison of Two Nationwide Cohorts

Background We aimed to explore the epidemiology of inflammatory bowel diseases [IBD] in association with the COVID-19 pandemic in two countries with different lockdown policies.Methods We utilized nationwide IBD cohorts in Israel and Sweden to explore the incidence of IBD during the pandemic compared to 3 years prior [2017-2019]. We examined temporal trends through the presence of inflection points by Joinpoint regression analysis and reported average monthly percentage changes [AMPC].Results A total of 155 837 patients with IBD were included [Israel, 58 640; Sweden, 97 197]. The annual incidence of IBD was stable until 2019 in both countries but then decreased in Israel (AAPC -16.6% [95% confidence interval, CI, -19.9% to -10.0%]) and remained stable in Sweden (AAPC -3.5% [95% CI -11.6% to 3.7%]). When exploring the monthly incidence during the pandemic, in Israel the rate remained stable until November 2020 (AMPC 2.3% [95% CI -13.4% to 29.9%]) and then decreased sharply (AMPC -6.4% [95% CI -20.8% to 17.0%] until February 2021 and to -20.1% [95% CI -38.9% to -4.7%] from February 2021), while in Sweden, which had a less stringent lockdown policy, it decreased slightly until July 2020 (AMPC -3.3% [95% CI -21.6% to 20.3%]), but increased thereafter (AMPC 13.6% [95% CI -12.6% to 27.0%]). The change of incidence rate in Sweden occurred mainly in elderly-onset patients, the only population with significant restrictions during the pandemic.Conclusion The incidence of IBD decreased during the pandemic in association with lockdowns, more so in Israel, which had more stringent policies. Future studies are needed to determine the long-term effect of the pandemic on IBD.