Giardiasis Diagnosis and Treatment Practices Among Commercially Insured Persons in the United States

Abstract

Background Giardiasis, the most common enteric parasitic infection in the United States, causes an estimated 1.2 million episodes of illness annually. Published clinical recommendations include readily available Giardia-specific diagnostic testing and antiparasitic drugs. We investigated sequences of giardiasis diagnostic and treatment events using MarketScan, a large health insurance claims database. Methods We created a longitudinal cohort of 2995 persons diagnosed with giardiasis (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 007.1) from 2006 to 2010, and analyzed claims occurring 90 days before to 90 days after initial diagnosis. We evaluated differences in number and sequence of visits, diagnostic tests, and prescriptions by age group (children 1–17 years, adults 18–64 years) using χ2 tests and data visualization software. Results Among 2995 patients (212 433 claims), 18% had a Giardia-specific test followed by or concurrent with an effective antiparasitic drug, without ineffective antibiotics. Almost two-thirds of patients had an antiparasitic and 27% had an antibiotic during the study window. Compared with children, adults more often had ≥3 visits before diagnosis (19% vs 15%; P = .02). Adults were also less likely to have a Giardia-specific diagnostic test (48% vs 58%; P < .001) and more likely to have an antibiotic prescription (28% vs 25%; P = .04). When Giardia-specific tests and antiparasitic and antibiotic prescriptions were examined, pediatric clinical event sequences most frequently began with a Giardia-specific test, whereas adult sequences most frequently began with an antiparasitic prescription. Conclusions Giardiasis care infrequently follows all aspects of clinical recommendations. Multiple differences between pediatric and adult care, despite age-agnostic recommendations, suggest opportunities for provider education or tailored guidance.

Treatment-refractory giardiasis: challenges and solutions

“…Intriguingly, treatment with antibiotics ineffective against Giardia occurs in 25% of adult patients with gastrointestinal illness before receiving a correct diagnosis for giardiasis and MTZ administration. 64 This interesting finding deserves further investigations. Giardia -induced dysbiosis in addition to unnecessary antibiotic treatment could potentially alter the gut flora promoting the proliferation of potentially pathogenic MTZ-resistant bacteria such as Clostridium difficile .…”

Giardiasis Outbreaks — United States, 2012–2017

“…Many patients endure symptoms long before they receive a diagnosis. For example, in a U.S. study of insurance claims data, one half of giardiasis patients required three or more office visits before the diagnosis was made; in >20% of patients, a giardiasis diagnostic code was not recorded until >30 days after the initial visit for gastrointestinal symptoms ( 6 ). Because Giardia organisms are excreted intermittently in feces, sensitivity of microscopy with the direct fluorescent antibody test (the standard for diagnosis) can be increased by collecting and testing three stool specimens from patients on separate days ( 7 , 8 ).…”

Hypereosinophilia in an infant – case report. The role of eosinophils in selected diseases

“…Tinidazole and albendazole have similar efficacy to metronidazole [23]. Although previous studies suggest high efficacy of azithromycin in the treatment of giardiasis, current reports do not confirm this [22,27,28]. Secondary eosinophilia develops as a result of a reaction dependent on the action of inflammatory cytokines, including IL-3, IL-5, and GM-CSF, which can indirectly lead to an increase in total IgE concentration [2][3][4].…”