Uptake of influenza vaccination among persons with inflammatory bowel disease, multiple sclerosis or rheumatoid arthritis: a population-based matched cohort study.

Background: Individuals with immune-mediated inflammatory diseases, such as inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, are at increased risk for influenza and related complications. We examined and compared the uptake of influenza vaccination among people with and without these diseases, as well as the influence of psychiatric comorbidity on vaccine uptake.

Methods: Using administrative data from Apr. 1, 1984, to Mar. 31, 2016, we conducted a retrospective matched cohort study in Manitoba, Canada. We matched persons 18 years of age or older who had a diagnosis of inflammatory bowel disease, multiple sclerosis or rheumatoid arthritis (the immune-mediated inflammatory disease cohorts) with persons who did not have these diagnoses (the control cohorts) on age, sex and region. We then identified cohort members with any mood or anxiety disorder (depression, anxiety disorders, bipolar disorder). We identified influenza vaccinations through billing codes. Using binomial regression, we modelled the difference in the proportion of the immune-mediated inflammatory disease and matched cohorts vaccinated annually, with adjustment for sociodemographic characteristics, comorbidity and immune therapy. We tested additive interaction effects between a person's cohort and presence of a mood or anxiety disorder.

Results: We identified 32 880 individuals with 1 or more immune-mediated inflammatory diseases (10 148 with inflammatory bowel disease, 6158 with multiple sclerosis and 16 975 with rheumatoid arthritis) and a total of 164 152 controls. In fiscal year 2015, 8668 (41.3%, 95% confidence interval [CI] 40.6% to 42.0%) of the 20 982 persons with an immune-mediated inflammatory disease received an influenza vaccination, a rate higher than among controls (35 238 of 104 634; 33.7%, 95% CI 33.4% to 34.0%). After adjustment, participants with an immune-mediated inflammatory disease but no mood or anxiety disorder had 6.44% (95% CI 5.79% to 7.10%) greater uptake of vaccination than participants without such a disease. Among participants without an immune-mediated inflammatory disease, having a mood or anxiety disorder was associated with 4.54% (95% CI 4.20% to 4.89%) greater uptake of vaccination. However, we observed a subadditive interaction between immune-mediated inflammatory disease and psychiatric status (-1.38%, 95% CI -2.26% to -0.50%).

Interpretation: Uptake of influenza vaccination was consistently low in populations with immune-mediated inflammatory disease, and although psychiatric morbidity is associated with greater vaccine uptake by Manitobans, it negatively interacts with these diseases to reduce uptake. Changes in care delivery are needed to mitigate this gap in care.