Dec. 20, 1999 (Minneapolis) -- An infection with Lyme disease usually does not necessitate long-term muscle and joint abnormalities and memory problems, according to a study published in this week's issue of the journal Annals of Internal Medicine. Although those with prior infections reported more joint pain and memory problems than those who never had Lyme disease, the two groups' physical examinations were quite similar, the authors write.
"Many people worry that certain health problems can surface years after the infection," lead author Nancy A. Shadick, MD, MPH, tells WebMD. "However, we compared people who have past Lyme disease with ... [those who never had it]. Although the Lyme disease group reported more pain and memory problems, formal testing showed no difference in the groups."
Lyme disease is a disorder of the heart, joints, brain, and skin acquired following a bite by an infected tick. Treatment with the antibiotic doxycycline is now the standard, and the improvement in treatment has been associated with improved outcomes, says Shadick. She says that the people in this study may have had better outcomes because more of them were treated with doxycycline than were patients in earlier studies. Shadick is an assistant professor of medicine at Harvard Medical School and a rheumatologist at Brigham and Women's Hospital in Boston, where she directs the Lyme disease center.
In this study, Shadick and colleagues sent a questionnaire to all 6,046 permanent residents of Nantucket Island who were at least 17 years old. Nantucket Island was chosen for its high prevalence of Lyme disease of 14.3%. The one-page survey was mailed up to three times from 1993 to 1996.
From the respondents, the investigators identified about 180 people who had either a history of Lyme disease or symptoms suggestive of prior infection. All people were confirmed by the investigators to have had a prior infection of Lyme disease by standards established by the CDC. They were then matched to 167 subjects who had not had Lyme disease.
They then underwent interviews and physicals by examiners who had no knowledge of the participants' Lyme disease status. The examination included assessments of memory and cognitive function, including a joint examination, an examination of tender points, a quality-of-life questionnaire, and memory tests.
The previously infected group had been free of the disease for an average of six years. Overall, the same group reported more symptoms than group never infected. In particular, those with a Lyme disease history also reported more memory impairment, joint pain, and fatigue. They also had more pain at the knees and hips as well as between the fingers, and more knee swelling, than did those never infected.
However, on all tests of patients' memory and mental functions, there was no difference between groups, say the authors. The groups also were similar in evaluations of muscle and joint abnormalities.
"This study indicates that, at least on the basis of objective measures, the long-term outcomes for Lyme disease patients seem to be good," Eugene Shapiro, MD, who is with Yale University in New Haven, Conn., tells WebMD in an interview seeking objective commentary. "I hope patients will find these results reassuring. Although some patients have a long-term problem with Lyme disease, such complications are rare. Most people do fine."