Healthcare-seeking behavior preceding diagnosis of Lyme neuroborreliosis: population-based nationwide matched nested case-control study.

ABSTRACT

OBJECTIVES: To identify diagnostic opportunities, we investigated healthcare-seeking behavior among patients with Lyme neuroborreliosis (LNB) within 28 weeks before diagnosis. METHODS: We conducted a population-based, nationwide matched nested case-control study (Denmark, 2009-2021). As cases, we included all Danish residents with LNB (positive Borrelia burgdorferi intrathecal antibody index test and cerebrospinal fluid pleocytosis). We randomly selected controls from the general population, matched 101 on date of birth and sex. Exposures were assignment of diagnostic codes for symptoms, contact to medical specialties, medical wandering, and undergoing diagnostic procedures. We calculated the weekly and 3-months proportion of individuals with exposures and calculated absolute risk differences with corresponding 95% confidence intervals (95%CI). RESULTS: We included 1,056 cases with LNB and 10,560 controls. Within 3 months before diagnosis, the most frequent assigned symptoms were pain (difference 13.0%, 95%CI 10.9-15.1). Cases with LNB exhibited increased contact to most specialties, particularly general practitioners (difference 48.7%, 95%CI 46.0-51.4), neurology (difference 14.3%, 95%CI 11.7-16.8), and internal medicine (difference 11.1%, 95%CI 8.7-13.5), and medical wandering (difference 17.1%, 95%CI 14.3-20.0). Common diagnostic procedures included imaging of the brain (difference 10.2, 95%CI 8.3-12.1), the spine (difference 8.8%, 85%CI 7.0-10.6), and the abdomen (difference 7.2%, 95%CI 5.4-9.1). The increase in healthcare-seeking behavior was observed up to 12 weeks preceding diagnosis. CONCLUSIONS: Pain appears to be an ambiguous symptom of LNB, potentially contributing to delays in establishing the correct diagnosis. It would be difficult to identify patients with LNB more effectively as the increased healthcare-seeking behavior preceding diagnosis is distributed across many medical specialties.