Predicting outcome in Guillain-Barré syndrome: international validation of the modified Erasmus GBS Outcome Score

Background and objectives: The clinical course and outcome of the Guillain-Barré syndrome (GBS) are diverse and vary among regions. The modified Erasmus GBS Outcome Score (mEGOS) is a clinical model that predicts the risk of walking inability in GBS patients, and was developed with data from Dutch patients. The study objective was to validate the mEGOS in the International GBS Outcome Study (IGOS) cohort and to improve its performance and region-specificity. Methods: We used prospective data from the first 1500 patients included in IGOS, aged ≥ 6 years and unable to walk independently. We evaluated if the mEGOS at entry and week 1 could predict the inability to walk unaided at 4 and 26 weeks in the full cohort and in regional subgroups, using two measures for model performance: (1) discrimination: area under the receiver operating characteristic curve (AUC), and (2) calibration: observed versus predicted probability of being unable to walk independently. To improve the model predictions we recalibrated the model containing the overall mEGOS score, without changing the individual predictive factors. Finally, we assessed the predictive ability of the individual factors. Results: For validation of mEGOS at entry 809 patients were eligible (Europe/North America n=677, Asia n=76, other=56), and 671 for validation of mEGOS at week 1 (Europe/North America n=563, Asia n=65, other=43). AUC-values were >0.7 in all regional subgroups. In the Europe/North America subgroup observed outcomes were worse than predicted, while in Asia observed outcomes were better than predicted. Recalibration improved model accuracy and enabled the development of a region-specific version for Europe/North America (mEGOS-Eu/NA). Similar to the original mEGOS, severe limb weakness and higher age were the predominant predictors of poor outcome in the IGOS cohort. Discussion: The mEGOS is a validated tool to predict the inability to walk unaided at 4 and 26 weeks in GBS patients, also in countries outside The Netherlands. We developed a region-specific version of mEGOS for patients from Europe/North America. Classification of evidence: This study provides Class II evidence that the mEGOS accurately predicts the inability to walk unaided at 4 and 26 weeks in GBS patients. Clinicaltrialsgov identifier: NCT01582763

An international perspective on preceding infections in Guillain-Barré syndrome: The IGOS-1000 cohort

Background and Objectives: Infections play a key role in the development of Guillain-Barré syndrome (GBS) and have been associated with specific clinical features and disease severity. The clinical variation of GBS across geographical regions has been suggested to be related to differences in the distribution of preceding infections, but this has not been studied on a large scale. Methods: We analyzed the first 1,000 patients included in the International GBS Outcome Study with available biosamples (n = 768) for the presence of a recent infection with Campylobacter jejuni, hepatitis E virus, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus. Results: Serologic evidence of a recent infection with C. jejuni was found in 228 (30%), M. pneumoniae in 77 (10%), hepatitis E virus in 23 (3%), cytomegalovirus in 30 (4%), and Epstein-Barr virus in 7 (1%) patients. Evidence of more than 1 recent infection was found in 49 (6%) of these patients. Symptoms of antecedent infections were reported in 556 patients (72%), and this proportion did not significantly differ between those testing positive or negative for a recent infection. The proportions of infections were similar across continents. The sensorimotor variant and the demyelinating electrophysiologic subtype were most frequent across all infection groups, although proportions were significantly higher in patients with a cytomegalovirus and significantly lower in those with a C. jejuni infection. C. jejuni–positive patients were more severely affected, indicated by a lower Medical Research Council sum score at nadir (p = 0.004) and a longer time to regain the ability to walk independently (p = 0.005). The pure motor variant and axonal electrophysiologic subtype were more frequent in Asian compared with American or European C. jejuni–positive patients (p < 0.001, resp. p = 0.001). Time to nadir was longer in the cytomegalovirus-positive patients (p = 0.004). Discussion: Across geographical regions, the distribution of infections was similar, but the association between infection and clinical phenotype differed. A mismatch between symptom reporting and serologic results and the high frequency of coinfections demonstrate the importance of broad serologic testing in identifying the most likely infectious trigger. The association between infections and outcome indicates their value for future prognostic models