The epidemiology of inflammatory bowel diseases during the COVID-19 pandemic: comparison of two nationwide cohorts.

Abstract

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. We utilized nationwide IBD cohorts in Israel and Sweden to explore the incidence of IBD during the pandemic compared to three 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). 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 and since, it decreased in Israel (AAPC of -16.6% [95%CI -19.9% to -10.0%]) and remained stable in Sweden (AAPC of -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 -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. 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.