Comparison of males versus females with culture-confirmed early Lyme disease at presentation and at 11-20 years after diagnosis

Outpatient visits before and after Lyme disease diagnosis in a Maryland employer-based health plan

BACKGROUND

Insurance claims data have been used to inform an understanding of Lyme disease epidemiology and cost of care, however few such studies have incorporated post-treatment symptoms following diagnosis. Using longitudinal data from a private, employer-based health plan in an endemic US state, we compared outpatient care utilization pre- and post-Lyme disease diagnosis. We hypothesized that utilization would be higher in the post-diagnosis period, and that temporal trends would differ by age and gender.

METHODS

Members with Lyme disease were required to have both a corresponding ICD-9 code and a fill of an antibiotic indicated for treatment of the infection within 30 days of diagnosis. A 2-year 'pre- diagnosis' period and a 2-year 'post-diagnosis period' were centered around the diagnosis month. Lyme disease-relevant outpatient care visits were defined as specific primary care, specialty care, or urgent care visits. Descriptive statistics examined visits during these pre- and post-diagnosis periods, and the association between these periods and the number of visits was explored using generalized linear mixed effects models adjusting for age, season of the year, and gender.

RESULTS

The rate of outpatient visits increased 26% from the pre to the post-Lyme disease diagnosis periods among our 317-member sample (rate ratio = 1.26 [1.18, 1.36], p < 0.001). Descriptively, care utilization increases appeared to persist across months in the post-diagnosis period. Women's care utilization increased by 36% (1.36 [1.24, 1.50], p < 0.001), a significantly higher increase than the 14% increase found among men (1.14 [1.02, 1.27], p = 0.017). This gender difference was mainly driven by adult members. We found a borderline significant 17% increase in visits for children < 18 years, (1.17 [0.99, 1.38], p = 0.068), and a 31% increase for adults ≥ 18 years (1.31 [1.21, 1.42], p < 0.001).

CONCLUSIONS

Although modest at the population level, the statistically significant increases in post-Lyme diagnosis outpatient care we observed were persistent and unevenly distributed across demographic and place of service categories. As Lyme disease cases continue to grow, so will the cumulative prevalence of persistent symptoms after treatment. Therefore, it will be important to confirm these findings and understand their significance for care utilization and cost, particularly against the backdrop of other post-acute infectious syndromes.

Risk factors for Lyme disease stage and manifestation using electronic health records

BACKGROUND

Little is known about risk factors for early (e.g., erythema migrans) and disseminated Lyme disease manifestations, such as arthritis, neurological complications, and carditis. No study has used both diagnoses and free text to classify Lyme disease by disease stage and manifestation.

METHODS

We identified Lyme disease cases in 2012-2016 in the electronic health record (EHR) of a large, integrated health system in Pennsylvania. We developed a rule-based text-matching algorithm using regular expressions to extract clinical data from free text. Lyme disease cases were then classified by stage and manifestation using data from both diagnoses and free text. Among cases classified by stage, we evaluated individual, community, and health care variables as predictors of disseminated stage (vs. early) disease using Poisson regression models with robust errors. Final models adjusted for sociodemographic factors, receipt of Medical Assistance (i.e., Medicaid, a proxy for low socioeconomic status), primary care contact, setting of diagnosis, season of diagnosis, and urban/rural status.

RESULTS

Among 7310 cases of Lyme disease, we classified 62% by stage. Overall, 23% were classified using both diagnoses and text, 26% were classified using diagnoses only, and 13% were classified using text only. Among the staged diagnoses (n = 4530), 30% were disseminated stage (762 arthritis, 426 neurological manifestations, 76 carditis, 95 secondary erythema migrans, and 76 other manifestations). In adjusted models, we found that persons on Medical Assistance at least 50% of time under observation, compared to never users, had a higher risk (risk ratio [95% confidence interval]) of disseminated Lyme disease (1.20 [1.05, 1.37]). Primary care contact (0.59 [0.54, 0.64]) and diagnosis in the urgent care (0.22 [0.17, 0.29]), compared to the outpatient setting, were associated with lower risk of disseminated Lyme disease.

CONCLUSIONS

The associations between insurance payor, primary care status, and diagnostic setting with disseminated Lyme disease suggest that lower socioeconomic status and less health care access could be linked with disseminated stage Lyme disease. Intervening on these factors could reduce the individual and health care burden of disseminated Lyme disease. Our findings demonstrate the value of both diagnostic and narrative text data to identify Lyme disease manifestations in the EHR.

The presenting characteristics of erythema migrans vary by age, sex, duration, and body location

PURPOSE

The erythema migrans (EM) skin lesion is often the first clinical sign of Lyme disease. Significant variability in EM presenting characteristics such as shape, color, pattern, and homogeneity, has been reported. We studied associations between these presenting characteristics, as well as whether they were associated with age, sex, EM duration, body location, and initiation of antibiotics.

METHODS

Two hundred and seventy one adult participants with early Lyme disease who had a physician-diagnosed EM skin lesion of ≥ 5 cm in diameter and ≤ 72 h of antibiotic treatment were enrolled. Participant demographics, clinical characteristics, and characteristics of their primary EM lesion were recorded.

RESULTS

After adjusting for potential confounders, EM size increased along with increasing EM duration to a peak of 14 days. Male EM were found to be on average 2.18 cm larger than female EM. The odds of a red (vs blue/red) EM were 65% lower in males compared to females, and were over 3 times as high for EM found on the pelvis, torso, or arm compared to the leg. Age remained a significant predictor of central clearing in adjusted models; for every 10-year increase in age, the odds of central clearing decreased 25%.

CONCLUSIONS

Given that EM remains a clinical diagnosis, it is essential that both physicians and the general public are aware of its varied manifestations. Our findings suggest possible patterns within this variability, with implications for prompt diagnosis and treatment initiation, as well as an understanding of the clinical spectrum of EM.

Post-treatment Lyme Disease as a Model for Persistent Symptoms in Lyme Disease

It has long been observed in clinical practice that a subset of patients with Lyme disease report a constellation of symptoms such as fatigue, cognitive difficulties, and musculoskeletal pain, which may last for a significant period of time. These symptoms, which can range from mild to severe, have been reported throughout the literature in both prospective and population-based studies in Lyme disease endemic regions. The etiology of these symptoms is unknown, however several illness-causing mechanisms have been hypothesized, including microbial persistence, host immune dysregulation through inflammatory or secondary autoimmune pathways, or altered neural networks, as in central sensitization. Evaluation and characterization of persistent symptoms in Lyme disease is complicated by potential independent, repeat exposures to B. burgdorferi, as well as the potential for co-morbid diseases with overlapping symptom profiles. Antibody testing for B. burgdorferi is an insensitive measure after treatment, and no other FDA-approved tests currently exist. As such, diagnosis presents a complex challenge for physicians, while the lived experience for patients is one marked by uncertainty and often illness invalidation. Currently, there are no FDA-approved pharmaceutical therapies, and the safety and efficacy of off-label and/or complementary therapies have not been well studied and are not agreed-upon within the medical community. Post-treatment Lyme disease represents a narrow, defined, mechanistically-neutral subset of this larger, more heterogeneous group of patients, and is a useful definition in research settings as an initial subgroup of study. The aim of this paper is to review the current literature on the diagnosis, etiology, risk factors, and treatment of patients with persistent symptoms in the context of Lyme disease. The meaning and relevance of existing patient subgroups will be discussed, as will future research priorities, including the need to develop illness biomarkers, elucidate the biologic mechanisms of disease, and drive improvements in therapeutic options.

Characterization of 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidases from Borrelia burgdorferi: Antibiotic targets for Lyme disease

BACKGROUND

Borrelia burgdorferi causes Lyme disease, the most common tick-borne illness in the United States. The Center for Disease Control and Prevention estimates that the occurrence of Lyme disease in the U.S. has now reached approximately 300,000 cases annually. Early stage Borrelia burgdorferi infections are generally treatable with oral antibiotics, but late stage disease is more difficult to treat and more likely to lead to post-treatment Lyme disease syndrome.

METHODS

Here we examine three unique 5'-methylthioadenosine/S-adenosylhomocysteine (MTA/SAH) nucleosidases (MTNs or MTANs, EC 3.2.2.9) responsible for salvage of adenine and methionine in B. burgdorferi and explore their potential as antibiotic targets to treat Lyme disease. Recombinant Borrelia MTNs were expressed and purified from E. coli. The enzymes were extensively characterized for activity, specificity, and inhibition using a UV spectrophotometric assay. In vitro antibiotic activities of MTN inhibitors were assessed using a bioluminescent BacTiter-Glo™ assay.

RESULTS

The three Borrelia MTNs showed unique activities against the native substrates MTA, SAH, and 5'-deoxyadenosine. Analysis of substrate analogs revealed that specific activity rapidly dropped as the length of the 5'-alkylthio substitution increased. Non-hydrolysable nucleoside transition state analogs demonstrated sub-nanomolar enzyme inhibition constants. Lastly, two late stage transition state analogs exerted in vitro IC₅₀ values of 0.3-0.4 μg/mL against cultured B. burgdorferi cells.

CONCLUSION

B. burgdorferi is unusual in that it expresses three distinct MTNs (cytoplasmic, membrane bound, and secreted) that are effectively inactivated by nucleoside analogs.

GENERAL SIGNIFICANCE

The Borrelia MTNs appear to be promising targets for developing new antibiotics to treat Lyme disease.

Impact of patient age on clinical features, serologic test reactivity and long-term outcome of culture-confirmed early Lyme disease

Whether age at time of diagnosis impacts the clinical presentation or long-term outcome of early Lyme disease is unknown. Subjects enrolled in this study had culture-confirmed early Lyme disease and were followed up annually in a long-term prospective study. Subjects ≤50years of age were compared with those who were ≥51years of age at time of study entry. Of the 283 enrolled subjects, the ≥51year old age group was significantly more likely to be female (P=0.0095) and to be compliant with long-term follow-up of at least 11years duration (P=0.0119). There were no significant differences between the two age groups with regard to any of the other variables assessed at presentation. For the 128 subjects who were followed up for 11-20years, there was no significant difference between the two age groups in the frequency, number or type of residual symptoms. The older age group at study entry, however, was significantly more likely to develop an intercurrent comorbidity (P=0.0017), and there was a trend toward a greater likelihood of having an intercurrent hospitalization (P=0.0311). Among the 128 subjects followed up for 11-20years, the older age group at study entry returned for a significantly greater number of follow-up visits (P=0.0129). In conclusion, older age at the time of diagnosis of early Lyme disease did not impact the initial clinical features or long-term outcome of this infection. Not unexpectedly, older patients had more comorbidities during long-term follow-up.