Influenza Vaccination in Patients with Diabetes: Exploration of the Healthy User in Pharmacoepidemiology Studies

• Author / Creator

  Achtymichuk, Karly A

• Pharmacoepidemiologic studies of preventive medications or therapies are prone to the healthy user bias, as patients who are prescribed and adhere to preventive medications/therapies are likely different than patients not receiving these medications in multiple aspects of their lives. These differences can be a source of bias in estimating the isolated effect of the medication/therapy under study. The objectives of this research were to explore characteristics and behaviors of patients who receive influenza vaccination, which has previously been shown to be a strong marker of healthy users. Two studies were conducted; the first study was done in a prospective cohort of adults with type 2 diabetes, and involved statistical modeling to identify predictors of influenza vaccine receipt, which included: taking preventive medications (e.g., aspirin, blood pressure medications and cholesterol-lowering medications) and having foot checks done by a healthcare professional. These associated behaviors reinforce the need for observational studies of influenza vaccine effectiveness to control for healthy user attributes in order to reduce associated biases. The second study involved building a healthy user index to be used for adjustment of bias in large administrative databases. The score was developed based on characteristics believed to be associated with the healthy user (identified using influenza vaccination as a prototypical surrogate) from the literature. The index was internally validated and significantly predicted influenza vaccination. Future research should be aimed at evaluating the ability of the index to control for healthy user bias in real-world observational studies of preventive medications/ therapies.

• Subjects / Keywords

  • Influenza vaccinations
  • Epidemiology
  • Healthy User Bias

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R38S4K13Q

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.