Characteristics and health behaviors of diabetic patients receiving influenza vaccination

Objective: Epidemiological research has posited a 'healthy user' bias in patients receiving influenza vaccination; thus we sought to evaluate potential healthy-user attributes and their associations with influenza vaccination. Research design & methods: Between 2011 and 2013, adults with type 2 diabetes were enrolled in a prospective cohort in Alberta, Canada. Information collected included sociodemographics, diabetes-related data (e.g., duration, complications), health behaviors (e.g., smoking status), functional health status, and satisfaction with healthcare. Data were collected by a mailed, self-administered survey. Multivariable logistic regression analyses were used to identify potential healthy-user attributes independently associated with influenza vaccination. Results: From a cohort of 2040 patients, 1287 (63%) reported receiving the influenza vaccine in the previous year. Average age of the cohort was 64 years (standard deviation 11) and 55% were male. In multivariable analysis, attributes independently associated with influenza vaccination included receiving preventive medications: aspirin (64% vs 44%; adjusted odds ratio, aOR 1.65,95% CI 1.34-2.04); blood pressure medications (76% vs 56%; aOR 1.36,95% CI 1.07-1.71); and cholesterol-lowering medications (74% vs 53%; aOR 1.50,95% CI 1.19-1.89), as well as having a healthcare professional check feet for lesions (47% vs 31%; aOR 1.39,95% CI 1.12-1.74). Additional covariates independently associated with influenza vaccination included: age over 65 years, respiratory disease, the number of additional comorbidities, and higher ratings of healthcare experience. Conclusion: Vaccinated diabetic patients exhibit many postulated attributes of 'healthy users', which has implications for the interpretation of epidemiological studies of influenza vaccine effectiveness, as well as targeting future vaccination campaigns. (C) 2015 Elsevier Ltd. All rights reserved.