Histoplasmosis-related Healthcare Use, Diagnosis, and Treatment in a Commercially Insured Population, United States.

BACKGROUND

Infections with Histoplasma can range from asymptomatic to life-threatening acute pulmonary or disseminated disease. Histoplasmosis can be challenging to diagnose and is widely underrecognized. We analyzed insurance claims data to better characterize histoplasmosis testing and treatment practices and its burden on patients.

METHODS

We used the IBM MarketScan Research Databases to identify patients with histoplasmosis (International Classification of Diseases, Ninth Revision, Clinical Modification codes 115.00-115.99) during 2012-2014. We analyzed claims in the 3 months before to the 1 year after diagnosis and examined differences between patients with probable (hospitalized or >1 outpatient visit) and suspected (1 outpatient visit) histoplasmosis.

RESULTS

Among 1935 patients (943 probable, 992 suspected), 54% had codes for symptoms or findings consistent with histoplasmosis and 35% had ≥2 healthcare visits in the 3 months before diagnosis. Overall, 646 (33%) had any fungal-specific laboratory test: histoplasmosis antibody test (n = 349 [18%]), Histoplasma antigen test (n = 349 [18%]), fungal smear (n = 294 [15%]), or fungal culture (n = 223 [12%]); 464 (24%) had a biopsy. Forty-nine percent of probable patients and 10% of suspected patients were prescribed antifungal medication in the outpatient setting. In total, 19% were hospitalized. Patients' last histoplasmosis-associated healthcare visits occurred a median of 6 months after diagnosis.

CONCLUSIONS

Some histoplasmosis patients experienced severe disease, apparent diagnostic delays, and prolonged illness, whereas other patients lacked symptoms and were likely diagnosed incidentally (eg, via biopsy). Low rates of histoplasmosis-specific testing also suggest incidental diagnoses and low provider suspicion, highlighting the need for improved awareness about this disease.