Estimation of the burden of Lyme borreliosis in Austria using hospital discharge data

Lyme borreliosis (LB) is the most common tick-borne disease in Europe and can manifest as localized erythema migrans (EM) or further disseminate into Lyme neuroborreliosis (LNB), Lyme arthritis (LA) or other rarer manifestations. Despite public health importance, LB is not a mandatorily notifiable disease in Austria, resulting in limited epidemiological data. To address this gap, this study aimed to estimate and characterize the incidence of hospitalized LB in Austria from 2015-2023 and to extrapolate medically-attended LB by manifestation using data from Germany. LB cases were identified from the Austrian National Public Health Institute’s hospital discharge database, based on ICD-10 codes. The data, which encompassed 225 hospitals, included patient demographics, reasons for hospitalization, length of stay, and unique patient identifiers. German hospital discharge data and published literature on medically-attended LB were utilized to extrapolate Austrian hospital discharge data to total medically-attended LB cases. The average incidence of hospitalized LB was 9.9/ 100,000 population per year (PPY) and accounted for a total of 100,006 days of hospitalization in 2015-2023. The incidence of hospitalized LB was highest in the summer months, among children and older adults, and in the states of Carinthia and Burgenland. The medically-attended incidence was estimated to be 232.9/ 100,000 PPY overall, with 214.6 and 18.3/ 100,000 PPY of EM and disseminated manifestations, respectively. These estimates of medically-attended LB offer valuable insights for public health decision-makers in Austria, emphasizing the burden of LB and the importance of interventions to mitigate the impact of LB.