Estimation of Background Incidence Rates of Guillain-Barré Syndrome in Germany - A Retrospective Cohort Study with Electronic Healthcare Data

Abstract

Background: The Guillain-Barré syndrome (GBS) occurs after infections and as an adverse reaction to vaccines. No detailed information on incidence rates (IRs) in Germany is available. Methods: This retrospective cohort study estimated age- and sex-specific IRs of GBS in Germany in the years 2007-2009 based on electronic healthcare data from the German Pharmacoepidemiological Research Database (GePaRD). Two case definitions were applied. GBS cases had a main discharge diagnosis of GBS. GBS_PROCEDURE cases in addition had codes for relevant diagnostic procedures. Crude and standardized IRs (SIRs) with 95% confidence intervals were stratified by year, age group, sex, region and season. IR ratios (IRRs) for each stratification factor were calculated by multivariable Poisson regression. Results: Among 13,297,678 persons, 889 (693) incident GBS (GBS_PROCEDURE) cases were identified. Overall SIRs per 100,000 person years were 2.4 (2.2-2.5) for GBS and 1.8 (1.7-2.0) for GBS_PROCEDURE. (S)IRs increased with age, peaking in the age group 70-79 years (IR GBS: 5.5 (4.7-6.5)) and were higher in males than in females (e.g., IR GBS: IRR = 1.5 (1.3-1.7)) and in February-April, as compared to the rest of the year. No regional pattern was observed. Conclusion: (S)IRs of GBS in Germany differed by age, sex and season and were comparable to those found in other studies. Results might be used as a comparator in vaccine safety monitoring.