Geographic variation in influenza vaccination among U.S. nursing home residents: A national study

Objectives: Estimates of influenza vaccine use are not available at the county level for U.S. nursing home (NH) residents but are critically necessary to guide the implementation of quality improvement programs aimed at increasing vaccination. Furthermore, estimates that account for differences in resident characteristics between counties are unavailable. We estimated risk-standardized vaccination rates (RSVRs) among short- and long-stay NH residents by U.S. county and identified drivers of geographic variation.

Methods: We conducted a retrospective cohort study utilizing 100% of 2013-2015 fee-for-service Medicare claims, Minimum Data Set assessments, Certification and Survey Provider Enhanced Reports, and Long-Term Care: Facts on Care in the U.S. We separately evaluated short-stay (<100 days) and long-stay (≥100 days) residents aged 65 and older across the 2013-2014 and 2014-2015 influenza seasons. We estimated RSVRs via hierarchical logistic regression adjusting for 32 resident-level covariates. We then used multivariable linear regression models to assess associations between county-level NHs predictors and RSVRs.

Results: The study cohort consisted of 2,817,217 residents in 14,658 NHs across 2798 counties. Short-stay residents had lower RSVRs than long-stay residents (2013-2014: median [interquartile range], 69.6% [62.8-74.5] vs 84.0% [80.8-86.4]), and there was wide variation within each population (range, 11.4-89.8 vs 49.1-92.6). Several modifiable facility-level characteristics were associated with increased RSVRs, including higher registered nurse to total nurse ratio and higher total staffing for licensed practical nurses, speech-language pathologists, and social workers. Characteristics associated with lower RSVRs included higher percentage of residents restrained, with a pressure ulcer, and NH-level hospitalizations per resident-year.

Conclusions: Substantial county-level variation in influenza vaccine use exists among short- and long-stay NH residents. Quality improvement interventions to improve vaccination rates can leverage these results to target NHs located in counties with lower risk-standardized vaccine use.