Design Nationwide population based cohort study using national registers.
Participants All Danish residents diagnosed during 1986-2016 as having Lyme neuroborreliosis (n=2067), defined as a positive Borrelia burgdorferi intrathecal antibody test and a clinical diagnosis of Lyme borreliosis, and a comparison cohort from the general population matched on sex and date of birth (n=20 670).
Main outcome measures Mortality rate ratios, incidence rate ratios of comorbidities, and differences in educational and social outcomes.
Results Mortality among patients with Lyme neuroborreliosis was not higher than in the general population (mortality rate ratio 0.90, 95% confidence interval 0.79 to 1.03). Lyme neuroborreliosis patients had increased risk of haematological (incidence rate ratio 3.07, 2.03 to 4.66) and non-melanoma skin cancers (1.49, 1.18 to 1.88). At diagnosis, Lyme neuroborreliosis patients had slightly higher employment and lower disability pension rates. After five years, patients and comparison cohort members had similar numbers of hospital contacts (difference −0.22, 95% confidence interval −0.45 to 0.02, in-hospital days/year; 0.37, −0.10 to 0.83, outpatient visits/year), employment rates (difference 1.5%, −2.1% to 5.1%), income (difference −1000, −20 000 to 18 000, Danish kroner), days of sick leave (difference −0.3, −3.5 to 3.0, per year), rates of receipt of a disability pension (difference −0.9%, −3.2% to 1.3%), and number of children (difference –0.10, −0.27 to 0.08). More patients were married (difference 4.8%, 2.2% to 7.4%) and had completed high school education (difference 7%, 1% to 12%).
Conclusion A verified diagnosis of Lyme neuroborreliosis had no substantial effect on long term survival, health, or educational/social functioning. Nevertheless, the diagnosis decreased labour market involvement marginally and was associated with increased risk of haematological and non-melanoma skin cancers.