Abstract: TH-PO1084
Flu Vaccination Rates in Adults with Kidney Diseases Across Flu Seasons: Effect of Mailed Fliers
Session Information
- CKD: Epidemiology, Risk Factors, and Other Conditions
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2301 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention
Authors
- Toth-Manikowski, Stephanie M., Healthmap Solutions, Tampa, Florida, United States
- Shaps, Howard, Healthmap Solutions, Tampa, Florida, United States
- Forte, Abigail, Healthmap Solutions, Tampa, Florida, United States
Background
Influenza (flu) vaccination lowers infection and flu-related complications in chronic kidney disease (CKD) and end-stage kidney disease (ESKD). In general populations, mailed flu fliers increase vaccine uptake. Healthmap Solutions, a kidney population health management company, mailed fliers to adults with CKD/ESKD to see how this impacted vaccination rates compared to controls.
Methods
Using payor claims, we identified adults with Stage 3-5 CKD/ESKD who weren't vaccinated against flu in the 2023-24 flu season and mailed them an educational flier prior to the 2024-25 flu season. We matched controls based on variables identified via LASSO selection: insurance type, age group, race/ethnicity, and rurality. The matching process used the nearest neighbor method (match ratio=1; caliper=0.2). A difference-in-differences (DID) analysis compared vaccine rates between the 2022-23 and 2024-25 flu seasons; the 2023-24 flu season was not used as a pre-treatment outcome for the DID analysis as it was used as part of the inclusion criteria.
Results
We matched 6,626 individuals. Covariate balance was strong; mean absolute standardized difference was 0.03 with no significant imbalances across variables (Table). Both groups had increased vaccination rates between flu seasons (intervention: 11.4% to 16.6%; controls: 17.0% to 21.7%), representing a relative increase of 9.0% over the control group's improvement. However, the effect of the flier campaign was minimal and not significant (absolute difference 0.4%, 95% CI: -1.4% to 2.2%, p=0.6).
Conclusion
Mailing fliers to CKD/ESKD adults previously been unvaccinated against flu was associated with a directionally positive impact which may have ultimately been attributed to chance rather than a true impact of the flier campaign. More studies are needed to identify strategies to boost vaccine uptake in this high-risk group.