Variation in influenza vaccine assessment, receipt, and refusal by the concentration of Medicare Advantage enrollees in U.S. nursing homes

Abstract

Background: More older adults enrolled in Medicare Advantage (MA) are entering nursing homes (NHs), and MA concentration could affect vaccination rates through shifts in resident characteristics and/or payer related influences on preventive services use. We investigated whether rates of influenza vaccination and refusal differ across NHs with varying concentrations of MA-enrolled residents. Methods: We analyzed 2014-2015 Medicare enrollment data and Minimum Data Set clinical assessments linked to NH-level characteristics, star ratings, and county-level MA penetration rates. The independent variable was the percentage of residents enrolled in MA at admission and categorized into three groups. We examined three NH-level outcomes: percentage of residents assessed and appropriately provided the influenza vaccine, receiving influenza vaccine, and refusing influenza vaccine. Results: There were 936,513 long-stay residents in 12,384 NHs. Categories for the prevalence of MA enrollment in NHs were low (0% to 3.3%; n=4131 NHs), moderate (3.4% to 18.6%; n=4127 NHs) and high (>18.6%; n=4126 NHs). Adjusting for covariates, influenza vaccination rates among long-stay residents were higher in NHs with moderate (1.7%, P<0.0001), or high (3.1%, P<0.0001) MA versus the lowest prevalence of MA. Influenza vaccine refusal was lower in NHs with moderate (-3.1%, P<0.0001), or high (-4.6% P<0.0001) MA compared with NHs with the lowest prevalence of MA. Among 753,616 short-stay residents in 12,205 NHs, there was no association between MA concentration and influenza vaccination receipt but vaccine refusal was greater in NHs with higher MA prevalence (high or moderate vs. low MA: 5.2%, P<0.0001). Conclusion: The relationship between MA concentration and influenza vaccination measures varied among post-acute and long-term NH residents. As MA takes a larger role in the Medicare program, and more MA beneficiaries enter NHs, there is need to consider how managed care can be leveraged to improve the delivery of preventive services such as influenza vaccinations in NH settings.