P767 Prevalence and incidence rates of inflammatory bowel disease among First Nations: Population-based evidence from Saskatchewan, Canada

Abstract

Background Worldwide, the epidemiology of inflammatory bowel disease (IBD) has been widely studied in the general population; however, there is limited-to-no evidence about IBD among Indigenous peoples, specifically among First Nations (FNs). Saskatchewan (SK) is a province in western Canada with a population of 1.1 million, 11% of whom are FNs. We aimed to estimate the prevalence, incidence, and trends of IBD among FNs in SK since 1999. Methods As part of a patient-oriented research project, we conducted a retrospective population-based study between 1999 and 2016 fiscal years using administrative data for the province of SK. A previously validated algorithm that required multiple health care contacts was applied to identify IBD cases (Crohn’s disease [CD] and ulcerative colitis [UC]). The ‘self-declared FN status’ variable in the Person Health Registration System was used to determine FNs meeting the IBD case definition and the population at risk. Generalised linear models (GLMs) with generalised estimated equations and a negative binomial distribution were used to estimate the annual prevalence of IBD, CD, and UC. Incidence rates and their corresponding 95% confidence intervals (95%CI) were estimated using GLMs with a negative binomial distribution. The GLMs were used to test trends overtime. Results The annual prevalence of IBD among FNs in SK increased from 64 (95%CI 62–66) per 100,000 people in 1999 to 142 (95%CI 140–144) per 100,000 population in 2016. Also, the prevalence of CD and UC increased during the study period, with 53/100,000 (95%CI 52–55) for CD and 87/100,000 (95%CI 86–89) for UC in 2016. The average increase in the prevalence of IBD was 4.2% (95%CI 3.2–5.2) per year, with similar trends observed in CD (4.1% [95%CI 3.3–4.9]) and UC (3.4% [95%CI 2.3–4.6]). The incidence rates of IBD among FNs were 11 (95%CI 5–25) per 100,000 people in 1999 and 3 (95%CI 1–11) per 100,000 population in 2016. No statistically significant changes were observed in the incidence rates over time (p = 0.09). Conclusion This study is the first epidemiological work providing detailed evidence of IBD among FNs. We identified that FNs have increasing trends in the prevalence of IBD, which has also been described in the Canadian general population. In contrast to the general population of Canada and other developed countries that have shown decreasing trends, the incidence rates of IBD among FNs appear to be stable over time. Also, among FNs, UC appears to be more prevalent than CD; this pattern has been observed in the general populations of developing countries. These results illuminate the need to advocate for better health care and wellness for FNs living with IBD.