Sex- and age-specific background incidence rates for various medical events in the German population aged ≥ 50 years using a nationwide monitoring system of claims data

Background incidence rates (BI) of diseases are crucial for interpreting medical events that occur in a temporal association with an intervention, such as vaccination. In 2018, a new adjuvanted herpes zoster (HZ) vaccine was introduced in Germany for use in adults aged ≥ 50 years. In this context, we assessed granular BI for 16 immune-related and other medical conditions in this age-group. Here, we describe the methodology applied and present exemplary results for Guillain-Barré syndrome (GBS), psoriasis and type 1 diabetes mellitus (T1DM). We used a data platform that contains outpatient claims data from all statutory health insured persons in Germany. We calculated sex- and age-specific incidence rates (IRs) in people aged ≥ 50 years in 2014–2016. To account for possible misestimation due to the use of solely outpatient data an “inpatient factor” was assessed using in- and outpatient claims data from a large German statutory health insurance company. In all age-strata IRs of GBS, psoriasis and T1DM were higher in men than in women and varied between age-groups. IR per 100,000 men and women was 5–8 and 3–5 for GBS, 268–430 and 230–412 for psoriasis and 26–39 and 15–28 for T1DM, respectively. The magnitude of the inpatient factor differed between diseases, sexes and age groups. The extensive data platform allows to assess sex- and age-specific IRs even for very rare conditions. IRs varied between sexes and age groups, stressing the importance of granular BI to interpret potential post-marketing, vaccine-related medical events, thereby supporting vaccine safety communication. • Background incidence rates facilitate safety monitoring of vaccines. • We calculated incidence rates for 16 conditions prior herpes zoster vaccine introduction. • Outpatient claims data were analyzed and stratified by sex, age, region, and year. • The results may be used for post-marketing surveillance of other vaccines as well.