The Growth and Reach of Lyme Disease
A new analysis sheds light on where the tick-borne infection is spreading and whom it’s affecting.
A tick, whose bite can transmit the Lyme disease.(BERTRAND GUAY/AFP/Getty Images)
Lyme disease is a growing public health issue, and a new white paper from FAIR Health offers fresh evidence of the extent of that growth.
Drawing on our database of over 30 billion private health care claim records, we found that from 2007 to 2018, claim lines with diagnoses of Lyme disease increased nationally by 117%. ("Claim lines" are the individual procedures or services listed on an insurance claim.)
Each year, according to the Centers for Disease Control and Prevention, approximately 300,000 Americans are diagnosed with Lyme disease. A bacterial infection transmitted through the bite of a tick, Lyme disease typically causes fever, fatigue, headache and a rash. It often can be treated with antibiotics, but can affect joints, the nervous system and the heart if untreated. Even with treatment, some patients still experience a long-term illness called post-treatment Lyme disease syndrome, which is sometimes called chronic Lyme disease. Its symptoms include fatigue, joint and muscle pain, and cognitive issues.
Here are some of our findings about Lyme disease.
Urban vs. Rural Growth
Lyme disease historically has been associated more with rural than urban areas. But the growth in claim lines from 2007 to 2018 was more pronounced in urban locations, where the increase was 121% compared with 105% in rural areas. This may be attributable in part to people from urban areas going to the country on vacation and picking up an infection that is only diagnosed when they return home to the city. Lyme disease also may be spreading increasingly to suburban and urban areas.
A Leader Among Tick-Borne Diseases
Lyme disease accounted for 94% of claim lines for tick-borne diseases in 2018. Among other tick-borne diseases, the one with the second-greatest share of claim lines was babesiosis, followed by tick-borne rickettsioses, a category that includes Rocky Mountain spotted fever.
In 2007, the five states that had the highest number of claim lines with Lyme disease diagnoses as a percentage of all medical claim lines by state were all in the Northeast. From highest to lowest, they were New Jersey, Rhode Island, Connecticut, Massachusetts and New York. This was in keeping with the historical association of the disease with that region.
But in 2018, one of the top five states – North Carolina – was in the South, while the rest were in the Northeast. The top five states that year were, from highest to lowest, New Jersey, Connecticut, Rhode Island, North Carolina and Vermont.
In both rural and urban areas in 2018, more claim lines with Lyme disease diagnoses were submitted for females than males. This differs from CDC data for 2018 showing that, among patients with reported confirmed and probable cases of Lyme disease, males accounted for more diagnoses than females.
The difference may be due to the fact that FAIR Health data is based on clinical diagnoses, while the CDC surveillance case definition relies primarily on laboratory evidence of infection. Some researchers also have suggested that female patients may be less likely than males to test positive for Lyme disease infection.
Distribution of claim lines with Lyme disease diagnoses by gender in rural (left) and urban (right) areas, 2018(Courtesy of FAIR Health)
In both rural and urban areas in 2018, individuals aged 51 to 60 held the largest share of the age distribution of Lyme disease claim lines. The age group 41 to 50 held the second-largest share in both rural and urban areas.
Distribution of claim lines with Lyme disease diagnoses by age group and rural or urban area, 2018(Courtesy of FAIR Health)
In 2018, July was the month with the highest share of claim lines for Lyme disease. The month with the lowest share was December.
Monthly distribution of claim lines with Lyme disease diagnoses, 2018(Courtesy of FAIR Health)
Patients who have been diagnosed with Lyme disease often are diagnosed with other conditions as well. In 2018, the 10 most common "other diagnoses" found in patients with Lyme disease were, in order from most to least common:
- General signs and symptoms (e.g., malaise and fatigue)
- Dorsopathies (disorders of the spine)
- Soft tissue disorders
- Other joint disorders
- Disorders of the thyroid gland
- Anxiety and other nonpsychotic mental disorders
- Skin and subcutaneous tissue symptoms
- Dermatitis and eczema
- Mood (affective) disorders
Each of these diagnoses was more common in patients with Lyme disease than in all patients. Many of these types of diagnoses – such as the malaise and fatigue component of general signs and symptoms, as well as soft tissue and joint disorders – have been linked in the past to either Lyme disease, chronic Lyme disease or both.
Much still remains unknown about Lyme disease. We conducted this study to help fill the gaps in knowledge about the condition, and to provide a foundation that can advance the work of other researchers.