1720. Regional Differences in Trends of Hospitalizations Associated with Tick-Borne Diseases in the United States, 2009-2014
Session: Oral Abstract Session: Public Health: Epidemiology and Outbreaks
Saturday, October 6, 2018: 8:45 AM
Room: S 157

Background: Tick-borne diseases are increasing in incidence in the United States, however limited data exist on regional trends of associated hospitalizations. Using a nationally distributed dataset of U.S. hospital-based medical records, we aimed to assess trends in incidence of hospitalizations from tick-borne disease by geographic region.

Methods: Data were examined from 156 U.S. hospitals from 2009-2014 to identify hospitalizations with tick-borne disease. Cases were described and Poisson regression used to estimate the annual percent change (APC) and associated 95% confidence intervals (CI) in incidence by region over time.

Results: Overall, 2,543 hospitalized patients with tick-borne disease were identified (average annual incidence=28.4 cases/100,000 hospitalized persons), including 1,613 (63%) with Lyme disease, 379 (15%) tick-borne fever, 293 (12%) ehrlichiosis, 93 (4%) babesiosis, 43 (2%) rickettsiosis, and 122 (4%) multiple tick-related diagnoses. Tick-borne diseases varied significantly by region, with Lyme disease more frequent in those residing in the Northeast (68%) than the South (57%) or West (42%) and tick-borne fever more common in the West (28%) versus the South (18%), Midwest (14%) and Northeast (13%) (p<0.0001). Significant increases in tick-borne disease hospitalizations were identified across nearly all U.S. regions, ranging from 15% per year in the South (95% CI=8-24%) to 45% per year in the West (34-58%), with the exception of the Northeast, where incidence declined by 6% per year (0.04-11%). Lyme disease hospitalizations showed similar trends, with the greatest increase in the South (APC=53%, 95% CI=33-76%) and a decrease in the Northeast (APC= 13%; 3%-23%). Hospitalizations with tick-borne fever increased in the Midwest (APC=49%; 8-206%) and Northeast (APC=18%; 4-34%); with ehrlichiosis increased in the West (APC=231%; 75-306%); and with babesiosis increased in the South (APC=50%; 12-201%) and the Midwest (APC=21%; 5-39%).

Conclusion: Incidence of hospitalizations from tick-borne disease is increasing throughout much of the nation, except in the Northeast where decreases in Lyme disease were observed. While hospitalizations with tick-borne diseases remain rare, the increases noted are substantial and may reflect rising incidence of these diseases within the represented states.

Jennifer Adjemian, PhD1,2, Yi Ling Lai, MPH2, Emily Ricotta, PhD, ScM2 and D. Rebecca Prevots, PhD, MPH2, (1)United States Public Health Service, Commissioned Corps, Rockville, MD, (2)Epidemiology Unit, Division of Intramural Research, NIAID, NIH, Bethesda, MD


J. Adjemian, None

Y. L. Lai, None

E. Ricotta, None

D. R. Prevots, None

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