Evaluating the Potential Misuse of the Lyme Disease Surveillance Case Definition

Lyme disease has been a nationally notifiable condition in the United States since 1991. As with other diseases, surveillance for Lyme disease relies on an explicit case definition to promote comparability of data across locations and time.¹ Although surveillance case definitions are based on key features of a disease, they are intended for the public health purposes of tracking trends and identifying populations at risk. They are not intended to be used by clinicians for making a clinical diagnosis or determining how to meet a patient’s health needs. Despite published disclaimers to this effect,² commentaries suggest that clinicians frequently rely on the Lyme disease case definition to diagnose patients, leaving some patients with Lyme disease untreated.^3,4 Congress also requested a report on how the Centers for Disease Control and Prevention is examining the potential misuse of the Lyme disease case definition.⁵

To evaluate potential use of the Lyme disease case definition by clinicians, Porter Novelli Public Services included questions about clinicians’ use of the Lyme disease case definition in its DocStyles 2018 survey,⁶ a computer-administered, nationally representative survey of family practice physicians (n = 483), internists (n = 518), pediatricians (n = 250), and nurse practitioners (n = 252). The first question stated, “Public health agencies have developed a national surveillance case definition for Lyme disease,” and then asked, “Which one of the following best describes how you diagnose and treat Lyme disease?” Answer choices were (1) I use my understanding of the disease and clinical judgment to make decisions, (2) I rely on the Lyme disease surveillance case definition to guide my decisions, and (3) I rarely see patients with Lyme disease in my practice. Of the 1503 clinicians surveyed, 739 (49.2%) indicated using their own judgment to make decisions, 188 (12.5%) indicated using the case definition to make decisions, and 576 (38.3%) indicated rarely seeing patients with Lyme disease.

Of 188 clinicians who said they used the case definition to guide decisions, knowledge of the case definition was limited. When asked if the case definition included information on diagnosis and management, 113 (60.1%) respondents stated that it did, 44 (23.4%) were unsure, and only 31 (16.4%) answered correctly that it did not. A total of 134 (71.3%) clinicians reported that they had treated fewer than 5 patients for Lyme disease in the previous 12 months.

Results from this national survey indicate that most clinicians do not use the surveillance case definition to make clinical decisions about diagnosis and treatment of Lyme disease. Nevertheless, some respondents reported doing so. Interpretation of this finding is complicated by evidence that most respondents who reported using the case definition were unfamiliar with its content. Further efforts to understand use of the Lyme disease surveillance case definition in clinical management are warranted.