Variations in Influenza and Pneumonia Immunizations for Medicare Beneficiaries Served by Rural Health Clinics.

The availability of a rural health clinic (RHC) database over the period of 6 years (2008-2013) offers a unique opportunity to examine the trends and patterns of disparities in immunization for influenza and pneumonia among Medicare beneficiaries in the southeastern states. The purpose of this exploratory study was twofold. First, it examined the rural trends and patterns of immunization rates before (2008-2009) and after (2010-2013) the Affordable Care Act (ACA) enactment by state and year. Second, it investigated how contextual, organizational, and aggregate patient characteristics may influence the variations in immunization for influenza and pneumonia of Medicare beneficiaries served by RHCs. Four data sources from federal agencies were merged to perform a longitudinal analysis of the influences of contextual, organizational, and aggregate patient characteristics on the disparities in immunization rates of rural Medicare beneficiaries for influenza and pneumonia. We included both time-varying and time-constant predictors in a multivariate analysis using Generalized Estimating Equation. This study revealed the increased immunization rates for both influenza and pneumonia over a period of 6 years. The ACA had a positive effect on increased immunization rates for pneumonia, but not for influenza, in rural Medicare beneficiaries in the eight states. The RHCs that served more dually-eligible patients had higher immunization rates. For influenza immunization, provider-based RHCs had a higher rate than the independent RHCs. For pneumonia immunization, no organizational variables were relevant in the explanation of the variability. The results also showed that no single dominant factor influenced health care disparities. This investigation suggested further improvements in preventive care are needed to target poor and isolated rural beneficiaries. Furthermore, the integration of immunization data from multiple sources is critically needed for understanding health disparities.