Prior studies have demonstrated that Lyme disease is frequently over-diagnosed. However, few studies describe which conditions are misdiagnosed as Lyme disease.
This retrospective observational cohort study evaluated patients referred for Lyme disease to a Maryland academic center between 2000-2013 who lacked evidence for Borrelia burgdorferi infection. The primary outcome is clinically described diagnoses contributing to symptoms. Secondary outcomes included symptom duration and determination whether diagnoses were new or attributed to existing medical conditions.
Of 1261 referred patients, 1061 had no findings of active Lyme disease, with 690 receiving other diagnoses.
Among the 690 patients, the median symptom duration was 796 days, and a total of 139 discrete diagnoses were made. Infectious disease diagnoses comprised only 3.2%. Leading diagnoses were anxiety/depression, fibromyalgia, chronic fatigue syndrome, migraine disorder, osteoarthritis and sleep disorder/apnea.
Examples of less frequent but non-syndromic diseases newly diagnosed included multiple sclerosis, malignancy, Parkinson's disease, sarcoidosis or amyotrophic lateral sclerosis.
Most patients with long-term symptoms have either new or pre-existing disorders accounting for their symptoms other than Lyme disease, suggesting overdiagnosis in this population. Patients referred for consideration of Lyme disease for chronic symptoms deserve careful assessment for diagnoses other than Borrelia burgdorferi infection.