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

https://doi.org/10.1016/j.jns.2017.04.006Get rights and content

Highlights

  • We estimated Puerto Rico's GBS incidence using ICD codes and medical records.

  • The adjusted GBS incidence was 1.7 per 100,000 population.

  • Most GBS cases (67%) occurred during July–September.

Abstract

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 7 days. 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.

Introduction

Guillain-Barré syndrome (GBS) is an autoimmune disease of the peripheral nervous system characterized by acute, symmetric limb weakness with decreased or absent deep-tendon reflexes [1]. Nearly 70% of patients with GBS report having had symptoms of an infectious illness in the days or weeks prior to onset of neurologic illness [2]. Infectious agents most frequently associated with the development of GBS include Campylobacter jejuni, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus [1], [2]. Infection with arthropod-borne viruses (arboviruses), such as dengue and chikungunya viruses, has also been associated with GBS [3], [4]. Globally, the annual incidence of GBS is estimated as 1.1–1.8 cases per 100,000 population [5], but estimates may vary depending on the regional prevalence of infectious triggers.

Increased incidence of GBS has been recently reported after the introduction of an emergent arbovirus, Zika virus, in French Polynesia [6] and the Americas [7], [8], [9]. However, many of the regions where Zika virus has recently emerged lack accurate estimates of GBS incidence. Such region-specific estimates are necessary to assess potential increases in GBS incidence due to Zika virus or other pathogens.

Zika virus transmission was first reported in Puerto Rico in December 2015, and the first GBS case with evidence of recent Zika virus infection had illness onset in January 2016 [10]. To assess the potential impact of Zika virus on GBS incidence in Puerto Rico, we sought to establish the GBS incidence prior to the widespread introduction of Zika virus using a combination of hospitalization administrative data and medical record reviews at a sample of nine reference hospitals. We also describe the clinical characteristics of patients with confirmed GBS managed at the same nine hospitals during 2012–2015.

Section snippets

Study population

We used 2013 data from the Puerto Rico Health Study, which includes island-wide medical insurance claims for medical encounters for approximately 90% of Puerto Rican residents [11]. Similar datasets were not available for other years. GBS cases were identified by using International Classification of Disease (ICD) discharge codes corresponding to GBS (i.e., ICD-9 code 357.0 or ICD-10 code G61.0).

Estimation of GBS incidence in 2013

To estimate the number of GBS cases in Puerto Rico in 2013, we identified all insurance claims for

Estimation of GBS incidence in 2013

Of 5643 insurance claims made in 2013 corresponding to GBS, 732 (13%) were for hospitalizations of 136 individual patients (Fig. 1). These 136 patients resulted in a crude GBS incidence of 3.8 per 100,000 population in 2013.

A total of 40 patients from the nine selected referral hospitals had inpatient codes for GBS in 2013. Of these, 18 (45%) met Brighton Collaboration criteria for confirmed GBS. After applying the proportion of confirmed cases from the nine hospitals (45%) to the previously

Discussion

Our investigation describes a method of estimating GBS incidence using a combination of hospitalization administrative data and medical record reviews. The adjusted GBS incidence in Puerto Rico in 2013 of 1.7 cases per 100,000 is consistent with estimates from other settings [5]. The number of GBS cases in these hospitals remained stable during 2012–2015 and most confirmed GBS cases in the nine referral hospitals had illness onset during July–September. IVIG was the most commonly used

Acknowledgments and funding

We thank Marrielle Mayshack from CDC for contributions to coordination and logistics. We also thank Jonathan Morales Gonzalez and Eddy Sanchez Hernandez from the Puerto Rico Department of Health for providing data from the Puerto Rico Health Study. We thank hospital leadership, medical records personnel, and infection control epidemiologists at the hospitals that assisted with this investigation (University District Hospital, Hospital Pediátrico Universitario, HIMA-San Pablo Caguas, HIMA-San

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