(C-256) Validation of Guillain-Barré Syndrome case identification in 4 heterogeneous real-world data sources in Spain and the United Kingdom using the Brighton Collaboration criteria.

Tuesday, August 26, 2025

12:00 PM - 1:30 PM ET

Location: Hall D

Co-Author(s)

MS

Mònica Sabaté

Clinical Pharmacology Service, Vall d’Hebron Hospital Universitari, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus., Spain
JR

Judit Riera-Arnau, MD

Clinical Pharmacology Service, Vall d’Hebron Hospital Universitari, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus., Catalonia, Spain
EB

Elena Ballarín

Clinical Pharmacology Service, Vall d’Hebron Hospital Universitari, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus., Spain
OP

Oleguer Parés-badell, MD

Preventive Medicine Service, Vall d’Hebron Hospital Universitari, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus., Spain
XM

Xavier Matínez, MD

Preventive Medicine Service, Vall d’Hebron Hospital Universitari, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus., Spain
JC

Juan José Carreras Martínez

Vaccine Research Department, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO-Public Health), Valencia, Spain, Spain

Presenting Author(s)

Felipe Villalobos

Primary care researcher
Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (IDIAPJGol), Barcelona, Spain, Spain

Co-Author(s)

AY

Alison Yeomans

Drug Safety Research Unit (DSRU), Southampton, UK
Southampton, UK, United Kingdom
KM

Kathryn Morton

Drug Safety Research Unit (DSRU), Southampton, UK, United Kingdom
AU

Arantxa Urchueguía

Vaccine Research Department, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO-Public Health), Valencia, Spain, Spain
MS

Martín Solórzano

Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (IDIAPJGol), Barcelona, Spain, Spain
DR

Debabrata Roy

Drug Safety Research Unit (DSRU), Southampton, UK, United Kingdom
EC

Elisa Correcher-Martínez, MSc

Vaccine Research Department, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO - Public Health), Valencia, Spain
Valencia, Spain
CB

Carlo Alberto Bissacco

Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (IDIAPJGol), Barcelona, Spain, Spain
TA

Taylor Aurelius

Drug Safety Research Unit (DSRU), Southampton, UK, United Kingdom

Presenting Author(s)

GD

Gianmarco Di Mauro

Teamit Institute, Partnerships, Barcelona Health Hub, Barcelona, Spain, Spain

Co-Author(s)

MS

Miriam C.J. Sturkenboom

Department of Data Science and Biostatistics, Julius Center for Health Science and Primary Care, University Medical Center of Utrecht, Utrecht University, Utrecht, The Netherlands, Netherlands

Background: Guillain-Barré Syndrome (GBS) is a rare autoimmune neurological disorder characterised by flaccid paralysis, weakness, and sensory disturbances in the extremities. The European Medicines Agency (EMA) issued a warning in July 2021 based on GBS cases following COVID-19 vaccine administration.

Objectives: As part of the Global COVID Vaccine Safety (GCoVS) study, we estimated the Positive Predictive Value (PPV) of the identification of GBS cases ascertained in multiple healthcare settings.

Methods: This study included two primary care (VID and SIDIAP) and one hospital database (VHUH) from Spain, and a United Kingdom primary care database (CPRD Aurum). GBS cases were identified via diagnostic codes recorded from December-2020 to November-2022 and classified using the Brighton Collaboration level of certainty (LOC) criteria. The validity of the GBS cases was assessed by calculating the PPV with Yates correction, for LOC1-2 cases, considered as true cases. Results were stratified by the risk window in which they occurred (within or outside 42 days post-vaccination) and the timing of the alert by regulatory agencies in July 2021 (before or after).

Results: 611 cases were identified in all databases. Validation was not conducted in CPRD due to lack of information required by the case criteria. Out from the 180 cases available, most were classified with LOC 4 (n=78) or 5 (n=55), except in VHUH. The PPVs varied among databases 4.8% in SIDIAP, 55.6% in VID and 90% in VHUH. VID showed an increase of the PPV when comparing the period before and after the regulatory alert (47.4% vs 61,5%, p< 0.001) while in SIDIAP and VHUH decreased (10.5% vs 3.8%, p=0.56; 100% vs 87.5%, p< 0.001). Risk-window analysis indicated a higher PPV within the risk window for VHUH (100% vs 87.5%, p=0.001) and lower for SIDIAP and VID (3.0 vs 5.4%, p=1.00; 36.4% vs 73.9%, p=0.99).

Conclusions: Most GBS cases were classified at level 4. Significant changes in PPV were observed in relation to the risk window in VID and VHUH, and in relation to the risk alert in VHUH only. No significant changes in PPV were noted in SIDIAP. The main differences in calculating the PPV stem from variation in the type of database and available information. Our findings underscore the need for access to source medical charts for retrospective validation of GBS using RWD.