OBJECTIVES: To estimate the association between county-level social vulnerability and rates of pneumococcal disease incidence among Medicare adult beneficiaries in the United States between 2016 and 2019.

METHODS: We calculated the county-level pneumococcal disease incidence among Medicare beneficiaries using 100% Medicare data available through the Chronic Conditions Data Warehouse Virtual Research Data Center. Pneumococcal disease incidence was measured for invasive pneumococcal disease (IPD), all-cause pneumonia (ACP), and pneumococcal pneumonia (PP) based on ICD-10 diagnoses from the inpatient and outpatient claims. Counties were categorized into quintiles of area-level social disadvantage by the Minority Health Social Vulnerability Index (MHSVI) and its six subthemes (socioeconomic status, household characteristics, racial and ethnic minority status, housing type and transportation, health care infrastructure and access, and medical vulnerability). Estimated differences in disease incidence across levels of social disadvantage were reported.

RESULTS:

Our study included 56,909,953 Medicare beneficiaries representing 194,850,826 Medicare member-years (2016-2019). For ACP, PP, and IPD, a statistically significant positive association between area-level vulnerability and disease incidence was detected when vulnerability was defined by the overall MHSVI, Socioeconomic Status, Household Characteristics, Housing Type and Transportation, Healthcare Infrastructure, or Medical Vulnerability, meaning more-vulnerable areas had higher disease incidence. Among these indices, the magnitude of disparities between the most- and least-vulnerable areas depends on the definition of vulnerability used. When area-level vulnerability was defined by the Racial and Ethnic Minority Status, we detected a statistically significant negative relationship between vulnerability and disease incidence, meaning more-vulnerable areas had lower disease incidence.

CONCLUSIONS:

This study adds to the growing body of work describing health inequities. The findings suggest that the specific definition of area-level measure of vulnerability is critical in accurately estimating geographic disparities in pneumococcal disease incidence. Capturing nuances in the definition of social vulnerability is important when considering how to improve access to health care and bolster prevention efforts.