Health Care Professionals’ Evidence-Based Medicine Internet Searches Closely Mimic the Known Seasonal Variation of Lyme Borreliosis: A Register-Based Study

BACKGROUND Both health care professionals and nonprofessionals seek medical information on the Internet. Using Web-based search engine searches to detect epidemic diseases has, however, been problematic. Physician's databases (PD) is a chargeable evidence-based medicine (EBM) portal on the Internet for health care professionals and is available throughout the entire health care system in Finland. Lyme borreliosis (LB), a well-defined disease model, shows temporal and regional variation in Finland. Little data exist on health care professionals' searches from Internet-based EBM databases in public health surveillance. OBJECTIVE The aim of this study was to assess whether health care professionals' use of Internet EBM databases could describe seasonal increases of the disease and supplement routine public health surveillance. METHODS Two registers, PD and the register of primary health care diagnoses (Avohilmo), were used to compare health care professionals' Internet searches on LB from EBM databases and national register-based LB diagnoses in order to evaluate annual and regional variations of LB in the whole country and in three selected high-incidence LB regions in Finland during 2011-2015. RESULTS Both registers, PD and Avohilmo, show visually similar patterns in annual and regional variation of LB in Finland and in the three high-incidence LB regions during 2011-2015. CONCLUSIONS Health care professionals' Internet searches from EBM databases coincide with national register diagnoses of LB. PD searches showed a clear seasonal variation. In addition, notable regional differences were present in both registers. However, physicians' Internet medical searches should be considered as a supplementary source of information for disease surveillance.