Characterizing Guillain-Barré Risk Factors Among Traditional Medicare Beneficiaries

Guillain-Barré Syndrome (GBS) is a rare and potentially life-threatening autoimmune disorder affecting the peripheral nerves. We sought to identify demographic and clinical characteristics associated with GBS onset. In this retrospective case-control study, we used national 2005 to 2020 fee-for-service Medicare claims data to identify beneficiaries with incident GBS using a chart-validated algorithm (N = 16 280), matched 1:1 with non-GBS controls (N = 16 280) by age, sex, race/ethnicity, number of preventive care visits, and year of diagnosis. We then used 2 separate modified Poisson regressions to model GBS onset as a function of preceding (≤42 days) and preexisting (>42 days) clinical conditions, while further adjusting for age, sex, race/ethnicity, socioeconomic status, disability status, rurality of residence, and year of diagnosis. Preexisting conditions associated with GBS included disorders of lipid metabolism (aOR(approx.) = 1.04, P = .03) and intestinal infection (aOR(approx.) = 1.05, P = .03). Preceding conditions associated with GBS included disorders of lipid metabolism (aOR(approx.) = 1.05, P = .01), delirium, dementia, and amnestic and other cognitive disorders (aOR(approx.) = 1.14, P = .0004), and chronic ulcer of skin (aOR(approx.) = 1.07, P = .01). In both models, GBS is positively associated with Medicare-Medicaid dual eligibility and disability status. Our hypothesis-generating findings suggest areas for further study into the mechanisms underlying GBS, raise interesting questions around the role of socioeconomic and structural factors in GBS, and demonstrate the potential of using claims data to study rare conditions.