Prevalence and Healthcare Burden of Fungal Infections in the United States, 2018

Abstract

Background: Fungal infections are responsible for >1.5 million deaths globally per year, primarily in those with compromised immune function. This is concerning as the number of immunocompromised patients, especially in those without human immunodeficiency virus (HIV), has risen in the past decade. The purpose of this analysis was to provide the current prevalence and impact of fungal disease in the United States.

Methods: We analyzed hospital discharge data from the most recent (2018) Healthcare Cost and Utilization Project National Inpatient Sample, and outpatient visit data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey. Costs are presented in 2018 United States (US) dollars.

Results: In the 35.5 million inpatient visits documented in 2018 in the US, approximately 666 235 fungal infections were diagnosed, with an estimated attributable cost of $6.7 billion. Aspergillus, Pneumocystis, and Candida infections accounted for 76.3% of fungal infections diagnosed, and 81.1% of associated costs. Most fungal disease occurred in patients with elevated risk of infection. The visit costs, lengths of stay, and risks of mortality in this population were more than twice that of those without fungal diagnoses. A further 6.6 million fungal infections were diagnosed during outpatient visits.

Conclusions: Fungal disease is a serious clinical concern with substantial healthcare costs and significant increases in morbidity and mortality, particularly among predisposed patients. Increased surveillance, standardized treatment guidelines, and improvement in diagnostics and therapeutics are needed to support the rising numbers of at-risk patients.

Keywords: HCUP; Healthcare Cost and Utilization Project; NIS; National Inpatient Sample; fungal disease; mortality; mycoses.

Figure 1.

Rate of fungal infections and associated risk condition diagnoses in the United States in 2018. The diagnostic rates per 100 000 inpatient visits of conditions associated with elevated risk of fungal disease (A), all fungal infections (B), invasive fungal infections (C), and noninvasive fungal infections (D). Rates are presented by geographic region.

Figure 2.

Changes in fungal disease diagnoses and direct costs between 2014 and 2018. The difference in the number of fungal infections diagnosed during inpatient visits (A) and the direct costs of these visits (B). Abbreviation: USD, United States dollars.

Figure 3.

Changes in fungal disease diagnoses and direct costs between 2014 and 2018. The ratio of average cost of inpatient visit, average length of stay, and relative risk of mortality associated with fungal diagnosis in patients with (A) and without (B) diagnosis of risk conditions associated with increased risk of fungal disease.