Misdiagnosis of Lyme Disease With Unnecessary Antimicrobial Treatment Characterizes Patients Referred to an Academic Infectious Diseases Clinic.

Background. Although Lyme disease is the most common vector-borne infection in the United States, diagnostic accuracy within community settings is not well characterized. Methods. A retrospective observational cohort study of patients referred to an academic center with a presumed diagnosis or concern for Lyme disease between 2000 and 2013 was performed to analyze diagnoses and treatments. Characteristics of those with Lyme disease and those misdiagnosed as having Lyme disease were compared. Results. Of 1261 patients, 911 (72.2%) did not have Lyme disease, 184 (14.6%) had active or recent Lyme disease, 150 (11.9%) had a remote history of Lyme disease, and 16 (1.3%) were identified as having possible Lyme disease. Patients without current Lyme disease were more likely to be female (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.08-2.45), to have had symptoms for >3 months (OR, 8.78; 95% CI, 5.87-13.1), to have higher symptom counts (OR per additional symptom, 1.08; 95% CI, 1.02-1.13), to have had more Lyme-related laboratory testing (OR per additional laboratory test, 1.17; 95% CI, 1.03-1.32), and to have been diagnosed with what were regarded as coinfections (OR, 3.13; 95% CI, 1.14-8.57). Of the 911 patients without Lyme disease, 764 (83.9%) had received antimicrobials to treat Lyme disease or their coinfections. The percentage of patients established to have Lyme disease was lower than in earlier studies of referred populations. Conclusions. Among patients referred to an academic Infectious Diseases practice for Lyme disease, incorrect diagnoses and unnecessary antibiotic treatment were common, both for Lyme disease and for coinfections.