GBS cases were obtained from all seven tertiary
health care centers in three countries. After approval
of the ethical committees, data from patients above
age of 18 were collected by retrospective analysis of
computer and paper hospital records from the period
2009 to 2013.The level of certainty of the diagnosis was made
according to the Brighton criteria .
Precipitating factors were considered relevant if they
appeared 3–42 days before GBS onset . Degree of disability was assessed according to
the Guillain-Barré Syndrome Disability Scale