Data and Statistical Analysis
zoster
REGRESSION, ZOSTER, INFLUENZA
We used descriptive statistics to define the characteristics of the study cohort. Continuous variables are described as medians and IQRs. Categorical variables are defined as proportions. The 2 study arms were compared using 2-sided tests of statistical significance (Stratified analyses were used to assess for intervention-effect heterogeneity based on the following variables: prior immunization history and use of immunosuppressive therapy. Age, sex, smoking status, duration of CD or UC, and current use of immunosuppressive therapy were examined individually for potential confounding of the primary outcome (influenza vaccine uptake) using univariable logistic regression analysis. All variables that affected the crude estimate of the relative risk of effectiveness by 10% or greater were included in the final multivariable model. The study was not powered for subgroup analyses or to detect differences among the other preventive health recommendations (pneumococcal, zoster, bone health, and skin screening); these were considered hypothesis-generating analyses.