Short-course therapy may be as effective as long-course therapy for patients with Lyme disease

Long-term survival rates without treatment failure for patients with Lyme disease treated with antibiotics were about 99%, regardless of the duration of therapy, according to results of a recent study published in Clinical Infectious Diseases.

Todd J. Kowalski, MD, of the section of infectious disease at the Gundersen Lutheran Health System in La Crosse, Wis., was involved with the retrospective cohort study and follow-up survey. “There seemed to be no benefit to using prolonged antimicrobial therapy to treat early Lyme disease,” he said. “Long-term outcomes of patients treated with 10 days of antimicrobial therapy were as good as those treated with longer courses of antibiotics.”

Kowalski said there were no differences in subjective complaints of joint and muscle aches, fatigue, difficulty sleeping or difficulties concentrating between patients treated with antibiotics for ≤10 days, 11 to 15 days or ≥16 days of antibiotics when patients were surveyed on average 4.5 years after diagnosis.

The study involved 607 patients diagnosed with early localized and early disseminated Lyme disease. The study was conducted from Jan. 1, 2000, through Dec. 31, 2004, in an area hyperendemic to the infection.

Results

Doxycycline therapy had been administered to 93% of the study patients.

Among the patients treated with doxycycline, 17% were treated for ≤10 days, 33% were treated for 11 to 15 days and 47% were treated for ≥16 days.

Two-year treatment failure-free survival rates were calculated:

• l99% among patients treated for less than or equal to 10 days.
• l98.9% among patients treated for 11 to 15 days.
• l99.2% among patients treated for greater than or equal to 16 days.

The researchers wrote that patients treated for ≥16 days had lower 36-item Short-Form Health Survey social functioning scores at follow-up. However, Kowalski said no other differences in those scores were observed.

“We also found that objective clinical evidence of treatment failure following treatment with appropriately targeted oral antimicrobial therapy was exceedingly rare,” Kowalski said.

Treatment failure criteria were met by 1% of patients (n=6). Clinical details for four of those patients suggested reinfection. One of those patients was treated with an inappropriate antibiotic and one developed a facial palsy early on in the treatment regimen.

The overall rate of reinfection was 4%.

Commentary

“There has been confusion and uncertainty among clinicians and patients about the appropriate duration of antibiotic therapy for early Lyme disease,” Kowalski said. “This study adds compelling data that refutes the idea that longer durations of antimicrobial therapy for early Lyme disease improves outcomes. Patient outcomes were essentially the same, no matter the duration of antimicrobial therapy received. We know that antibiotic use always comes with some level of risk in terms of side effects, adverse reactions and resistance. Thus, our study demonstrates that prolonged courses of antimicrobial therapy for early Lyme disease does not seem justified.”

He said the study demonstrated that objective treatment failure was rare. However, he noted that there was a 4% rate of reinfection with Borrelia burgdorferi.

Kowalski said the study was conducted in an area hyperendemic for Lyme disease, and the duration of study follow-up was longer than in many previous studies of the infection.

“The location of the study at least in part explains the relatively high reinfection rate,” he said. “However, it highlights the importance of educating patients about tick prevention measures.” – by Rob Volansky

Kowalski TJ. Clin Infect Dis. 2010;50:512-520.

This article indicates that treatment failure is extremely rare in patients treated for either early Lyme disease (single erythema migrans), which accounts for about two-thirds of cases of Lyme disease, or early disseminated Lyme disease, which accounts for more than 20% of cases of Lyme disease in the United States. Furthermore, patients treated with a relatively short course of antibiotics (<10 days) had outcomes similar to those of patients treated with longer courses of antibiotics.

This is consistent with laboratory studies of Borrelia burgdorferi, the bacterium that causes Lyme disease, which demonstrate that this bacterium is extremely susceptible to antibiotics. It is also consistent with another study by Gary Wormser, MD, that showed that patients with erythema migrans can be treated effectively with 10 days of an antibiotic.

Of course, most patients who received <10 days of treatment in the study by Kowalski had early localized Lyme disease, and it might not be valid to conclude that 10 days of treatment is equally effective for patients with early disseminated Lyme disease.

The most important conclusion is that virtually all of the patients were treated effectively with a single course of treatment, and that the few “treatment failures” actually either had a new infection from a subsequent tick bite or had not received proper treatment initially.

–Eugene D. Shapiro, MD
Infectious Diseases in Children Editorial Board