VACCINE UTILIZATION PATTERNS AND PREDICTORS AMONG OLDER ADULTS WITH A HISTORY OF GUILLAIN-BARRE SYNDROME

Some vaccines have a small risk of triggering Guillain-Barré Syndrome (GBS), an autoimmune disorder that causes paralysis. There is no guidance for patients with a history of GBS regarding subsequent vaccination beyond a CDC precaution for patients whose GBS was vaccine-associated (GBS occurring within 42 days of vaccination). Patients and providers may consider prior GBS when making decisions about vaccines. The objectives were to describe vaccine patterns before and after GBS diagnosis (Aim 1) and describe predictors of vaccination one year after diagnosis (Aim 2). The data source was a 20% random sample of fee-for-service Medicare beneficiaries with Parts A, B, and D coverage for years 2006-2019. We identified beneficiaries ≥ age 66 at their first observed GBS hospitalization discharge diagnosis code (index date) with one year of prior enrollment in Parts A and B. We identified claims for 10 CDC-recommended vaccines for ages ≥65, measles-mumps-rubella, live-attenuated influenza, and human papillomavirus vaccines. We matched each patient with GBS to 5 non-GBS comparators on sex, racial and ethnic category, exact age, state of residence, and month of preventive health visits. For Aim 1, we used SMR weights to balance GBS patients and comparators on measures of healthcare use and indicators of frailty and comorbidity. We estimated weighted mean cumulative counts (wMCC) of vaccinations during one year before and year after GBS diagnosis, accounting for competing events and differential follow-up. For Aim 2, we used logistic LASSO regression models to identify predictors of vaccination one year after the index date and constructed logistic regression models using LASSO-identified predictors. One year after the index date, GBS patients received 26 vaccines/100 people (95% CI 23, 28), 41 fewer than matched non-GBS comparators (95% CI -44, -38). GBS diagnosis was a strong negative predictor of vaccination. Comparators had a strong positive association between increasing outpatient visits and vaccination while GBS patients had no association. The proportion of vaccinated patients increased across calendar time for comparators and declined slightly for GBS patients. Opportunities may exist to increase GBS patient vaccination overall and during outpatient visits. Future work should assess provider recommendations and patient motivations for vaccination.