NEW HAVEN, Conn. - Overtreatment and overdiagnosis of Lyme disease have become associated with inappropriate use of health services, avoidable treatment-related illness and substantial disability and distress, according to a study from Yale University's School of Medicine.
The study indicates that apprehensive patients can also cause doctors to hastily prescribe treatments without fully recognizing the consequences. Although some of the improper treatment and diagnosis was "patient driven," some responsibility did lay with the attending physician, researchers said.
Of the 209 patients studied, 60% turned out not to have Lyme disease at all, but still made an average of seven visits to a doctor, had four blood tests and underwent 42 days of antibiotic treatment. Of that group, 42% said they suffered depression after becoming convinced they had the disease. More than half reported adverse events from the antibiotics and 20% sought additional treatment.
Lyme disease remains one of the most difficult diseases to treat because the symptoms may mimic other illnesses and lab tests are often unreliable. Current endemic areas include the northeastern coast of the United States, the upper Midwest and northern California into Oregon. Ticks carry the infection and transmit the Borrelia burgdorferi spirochete.
Much has been learned about Lyme disease since it was first diagnosed more than two decades ago. It is a multi-stage bacterial infection that is difficult to diagnose and treat. It can also progress into a disease with debilitating symptoms including arthritis, cardiovascular and neurological problems. It has rapidly become the most common tickborne illness, with nearly 100,000 cases reported in the United States since 1982. In 1996 alone, more than 16,000 cases were reported - a 32-fold increase since the Centers for Disease Control and Prevention (CDC) began collecting surveillance data on the disease. However, this is a figure that most experts agree represents only a fraction of the cases that actually occur.
The study patients were evaluated between April 1994 and May 1995. Patients entered the study with a Lyme disease diagnosis previously made by either referring doctors or the patients themselves. Data were obtained on all patients through a 50-item questionnaire. They also underwent comprehensive physical exam and serologic testing for the disease and agreed to follow-up exams.
To identify adverse drug events, the patients were asked to report the name of the drug used, the duration of therapy, the mode of administration and whether any unanticipated reactions occurred with each course of antibiotic treatment. Patients were instructed to document any reaction to their treatment. If patients thought that an antibiotic treatment had caused a reaction that was not listed, they were instructed to record those reactions as well.
A diagnosis of active Lyme disease required the presence of erythema migrans or characteristic articular, neurologic or cardiac manifestations with serologic confirmation. A comprehensive history was taken and medical records were reviewed, as well as a complete physical exam. Serologic testing was performed by enzyme-linked immunosorbent assay (ELISA). A titer of 1:200 or greater for IgM or IgG was considered a positive result.
All specimens with positive ELISA results were subsequently tested for IgM and IgG antibodies in the laboratory by doing Western blot analysis using a two-step procedure and were evaluated according to CDC criteria.
For antibiotic reactions, minor events were defined as reactions that were self-limiting and did not require discontinuation of antibiotic therapy, or that required doctor intervention but was not serious or life-threatening. A major event was defined as any drug reaction that was potentially serious or life-threatening.
As stated above, 60% of the study's patients lacked any evidence of previous or active Lyme disease, according to the researchers. Most of the patients had been previously told they had Lyme disease, and 75% had received at least one course of antibiotic treatment. About one-third of these patients were thought to have a non-specific fatigue-arthralgia-myalgia syndrome. More than half of those had treatable disorders, such as depression, rheumatoid arthritis, bursitis and myasthenia gravis.
"Failure to diagnose and treat these conditions represents an additional type of treatment-related illness," said M. Carrington Reid, MD, PhD, associate professor of medicine at Yale Medical School. "We think our findings reflect a widespread phenomenon in current management of [Lyme disease]."
Inappropriate use of health services was great among those patients with no active Lyme disease. These patients had a median of four serologic tests, seven office visits and 42 days of antibiotic treatment. Drug therapy resulted in unavoidable treatment-related illness that included minor adverse drug reactions, such as diarrhea and stomach cramps.
There was also a large amount of disability and depression found among patients with no evidence of Lyme disease. Researchers speculated that many patients and doctors viewed the disease as a chronic and often incurable illness that required multiple courses of antibiotic treatment. A physician diagnosis, as opposed to self-diagnosis, reinforced this belief and contributed to increased depression and stress.
Reid and his team recommend that serologic tests only be performed when trying to confirm a well-formulated clinical suspicion of Lyme disease. The use of protracted courses of antibiotic therapy should be avoided because active Lyme disease is effectively treated, with very few exceptions, by a single course of antibiotics.
Patients with active disease should be assured that complete resolution of symptoms is expected but may not occur for several months. Also, among patients who present with non-specific symptoms, a diagnosis of other treatable conditions should be considered. And finally, for many patients who present with a presumptive diagnosis of Lyme disease and lack evidence of active infection, customary reassurance may not suffice - simply removing the Lyme disease label may not be enough for most patients.
For more information:
- Reid MC, Schoen R. The consequences of overdiagnosis and overtreatment of Lyme disease: an observational study. Ann Intern Med. 1998:128;354-62.
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