Incidence and clinical characteristics of Guillain-Barré syndrome before the introduction of Zika virus in Puerto Rico

Background: Zika virus has been associated with increases in Guillain-Barré syndrome (GBS) incidence. A GBS incidence estimation and clinical description was performed to assess baseline GBS epidemiology before the introduction of Zika virus in Puerto Rico.

Methods: Hospitalization administrative data from an island-wide insurance claims database and U.S. Census Bureau population estimates provided a crude GBS incidence for 2013. This estimate was adjusted using the proportion of GBS cases meeting Brighton criteria for confirmed GBS from nine reference hospitals. Characteristics of confirmed GBS cases in the same nine hospitals during 2012-2015 are described.

Results: A total of 136 GBS hospitalization claims were filed in 2013 (crude GBS incidence was 3.8 per 100,000 population). The adjusted GBS incidence was 1.7 per 100,000 population. Of 67 confirmed GBS cases during 2012-2015, 66% had an antecedent illness. Median time from antecedent illness to GBS onset was 7days. Most cases (67%) occurred during July-September.

Conclusions: Puerto Rico's GBS incidence for 2013 was estimated using a combination of administrative data and medical records review; this method could be employed in other regions to monitor GBS incidence before and after the introduction of GBS infectious triggers.