To compare the direct and indirect medical costs for patients with suspected Lyme borreliosis according to whether or not they had used an informal care pathway.

We retraced the care pathways of participating patients by a prospective questionnaire survey and a retrospective analysis of care records. Direct and indirect costs were estimated using a micro-costing method from different perspectives. We compared the costs of patients who had consulted a “Lyme Doctor” (informal care pathway) with those who had only used the formal care pathway. Non-parametric tests were appraised the significance of the differences between the two groups of patients.

Out of 103 eligible patients, 49 (including 12 having used an informal health care pathway) agreed to be investigated. Five expenditure items entirely borne by patients were significantly higher for patients following an informal care pathway: productivity loss (3041 ± 6580 vs 194 ± 1177 euros, p = 0.01), alternative therapies (3484 ± 7308 vs 369 ± 956 euros), biological tests sent abroad (571 ± 1415 vs 17 ± 92 euros, p < 0.01), self-medication (918 ± 1998 vs 133 ± 689, p = 0.02) and transport (3 094 ± 3456 vs 1 123 ± 1903p = 0.01).

From the patient’s standpoint, the informal care pathway involving consultation with a Lyme Doctor is far more expensive than the formal care pathway. More specifically, the patient has to bear the costs of alternative treatments and repeated, non-recommended examinations.