Cochrane Review and Neurologic Lyme Disease: Missing U.S. Evidence

A Cochrane review evaluating antibiotic treatment for neurologic Lyme disease highlights important findings—but also notable gaps. While several European trials were included, no U.S.-based studies on chronic neurologic Lyme disease met inclusion criteria.

This raises an important question: how should clinicians interpret evidence when major studies are excluded from systematic reviews?

In the Cochrane review Antibiotics for the neurological complications of Lyme disease, Cadavid and colleagues identified randomized trials conducted in Europe.

These studies reported generally favorable outcomes. “The majority of people are reported to have good outcomes, and symptoms resolve by 12 months regardless of the antibiotic used,” the authors note. Doxycycline, penicillin G, ceftriaxone, and cefotaxime were found to be effective in treating European Lyme neuroborreliosis.

Absence of U.S. Trials in the Review

No U.S.-based trials on chronic neurologic Lyme disease were included in the Cochrane analysis.

The authors excluded non-randomized and uncontrolled studies, including case series and observational data. As a result, several well-known U.S. studies were not considered.

Evidence from U.S. Studies

Earlier studies have described persistent neurologic manifestations of Lyme disease and variable responses to treatment.

• In a chronic neurologic Lyme disease series, 63% of patients improved after 2 weeks of intravenous ceftriaxone, while 22% relapsed and 15% did not improve
• In Lyme encephalopathy, 26% returned to normal, 32% improved significantly, and others had partial or no improvement
• An NIH-sponsored trial reported improvement in fatigue but not in cognitive outcomes after extended antibiotic therapy

Interpreting the Evidence

The exclusion of non-randomized studies highlights the limitations of relying solely on randomized controlled trials in complex conditions such as neurologic Lyme disease.

While randomized trials provide high-quality evidence, observational studies and case series may offer additional clinical insight, particularly when randomized data are limited.

Clinical Perspective

Clinicians treating patients with neurologic Lyme disease may need to consider a broader range of evidence beyond systematic reviews.

Understanding the strengths and limitations of different study designs may help guide clinical decision-making in complex cases.

Patients may benefit from review of Lyme disease symptoms, understanding testing limitations, and consideration of coinfections in persistent neurologic illness.

References

1. Cadavid D et al. Antibiotics for neurologic Lyme disease. Cochrane Database Syst Rev. 2016.
2. Logigian EL et al. Chronic neurologic manifestations of Lyme disease. N Engl J Med. 1990.
3. Logigian EL et al. Lyme encephalopathy treatment. J Infect Dis. 1999.
4. Fallon BA et al. IV antibiotic trial for Lyme encephalopathy. Neurology. 2008.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention