Epidemiology and Direct Health Care Cost of Inflammatory Bowel Disease in Saskatchewan: A Population-Based Study

Abstract

Worldwide studies have described an increasing prevalence of inflammatory bowel disease (IBD). Canada is a country with one of the highest IBD prevalence and incidence rates and with an estimated direct health care cost of $1.2 billion in 2018. Also, evidence shows variations in the incidence rate trends over time across Canadian provinces. This study aimed to estimate and test the trends of the incidence, prevalence, and direct health care cost of IBD in Saskatchewan from 1999 to 2016.

Administrative health data from Saskatchewan was used in a population-based cohort study from 1999 to 2016 fiscal years. A previously validated case definition was applied to identify individuals with a diagnosis of IBD. Generalized linear models with negative binomial and gamma distribution were used to model the prevalence/incidence and direct health care cost trends, respectively. Generalized estimating equations were used to account for correlation in the prevalence data. Sex, age group, and rural/urban residence were included as controlling variables. Annual prevalence and incidence rates, average annual changes, and direct health care cost (in 2013 Canadian dollars) were reported with their 95% confidence intervals (95%CI).

In 2016/17, 6,468 IBD cases were observed in our cohort; Crohn’s disease: 3,663 (56.6%), ulcerative colitis: 2,805 (43.4%). The prevalence of IBD increased from 341/100,000 (95%CI 340 to 341) in 1999/00 to 664/100,000 (95%CI 663 to 665) population in 2016/17, observing a 3.3% (95%CI 2.4 to 4.3) average annual increase. Also, the estimated health care cost of IBD increased from $1.8 (95%CI 1.6 to 2.0) thousand in 1999/00 to $7.0 (95%CI 6.5 to 7.5) thousand in 2016/17, 9.2% (95% CI 8.6 to 9.9) average annual increase. On the other hand, the incidence rate of IBD declined from 75/100,000 (95%CI 67 to 84) in 1999/00 to 15/100,000 (95%CI 12 to 18) population in 2016/17, corresponding to an average annual decrease of 6.9% (95%CI -7.6 to -6.2).

In conclusion, while a remarkable increase was found in the prevalence and direct health care cost of IBD in Saskatchewan, Canada, a significant decline in the IBD incidence rate of the disease was observed since 1999. Decision-makers and health care providers need to promote policies that face the rising burden of the disease in the province.