Lyme disease case definition misused. Perspective.

A recent article “Evaluating the Potential Misuse of the Lyme Disease Surveillance Case Definition,” by Perea and colleagues [1] highlights a concern that I have raised in previous blog posts. That is, are doctors incorrectly relying on the Centers for Disease Control and Prevention (CDC) surveillance definition when evaluating and diagnosing patients?

“Many physicians will mistakenly defer to the CDC’s Lyme disease case definition in making a diagnosis. These clinicians require that patients meet this strict and narrow criteria in order to be diagnosed with the disease.” [2]

“However, this definition was designed as a surveillance monitoring tool to track the number of Lyme disease cases throughout the country. It was not meant to be used in making a clinical diagnosis.”

Recently, Perea and colleagues surveyed 1,503 family practice physicians, internists, pediatricians, and nurse practitioners on their use of the Lyme disease case definition. Participants were asked the following questions:

“Which one of the following best describes how you diagnose and treat Lyme disease?”

• Over 60% of those clinicians surveyed reported treating Lyme disease patients.
• Out of the 927 clinicians treating Lyme disease patients, 20% reported relying on the CDC’s surveillance case definition to guide their decisions.
• However, out of the 20% of clinicians who said they rely on the case definition, “knowledge of the case definition was limited.”

“Does the case definition include information on diagnosis and management?”

The clinicians who did rely on the CDC’s case definition were asked if the case definition included information on diagnosis and management.

• “Only 31 (16.4%) answered correctly that it did not.” Hence, the majority believed the CDC’s definition included diagnostic and treatment guidance.

The authors’ findings support the conclusion that there are still doctors who misuse the Lyme disease surveillance case definition. However, they point out that, “Interpretation of this finding is complicated by evidence that most respondents who reported using the case definition were unfamiliar with its content.”