Epidemiology of Lyme Borreliosis in France in Primary Care and Hospital Settings, 2010-2019.

Lyme borreliosis (LB) is a growing public health concern requiring accurate and comprehensive epidemiological knowledge to inform health care interventions. This study compared the epidemiology of LB in primary care and hospital settings, using for the first time in France three sources of data, and highlighted specific populations at higher risk of developing LB. This study analyzed data from general practitioner networks (., Sentinel network, Electronic Medical Records [EMR]) and the national hospital discharge database to describe the LB epidemiology from 2010 to 2019. The average annual incidence rates of LB in primary care increased from 42.3 cases/100,000 population in 2010-2012 to 83.0/100,000 in 2017-2019 for the Sentinel Network and 42.7/100,000 to 74.6/100,000 for the EMR, following a marked rise in 2016. The annual hospitalization rate remained stable from 2012 to 2019 fluctuating between 1.6 and 1.8 hospitalizations/100,000. Women were more likely to present with LB in primary care setting compared with men (male-to-female incidence rate ratio [IRR] = 0.92), whereas men were predominant among hospitalizations (IRR = 1.4), with the largest discordance among adolescents aged 10-14 years (IRR = 1.8) and adults aged 80 years and older (IRR = 2.5). In 2017-2019, the average annual incidence rate peaked among persons aged 60-69 years in primary care (>125/100,000) and aged 70-79 years among hospitalized patients (3.4/100,000). A second peak occurred in children aged 0-4 or 5-9 years depending on sources. Incidence rates in Limousin and the north-eastern regions were the highest for both primary care and hospital settings. Analyses showed disparities in the evolution of incidence, sex-specific incidence rates, and predominant age groups between primary care and hospital settings that merit further exploration.