Listen to The Mould Show Podcast on ITunes

Key factors associated with fungal infection risk are socio-demographic factors such as age, gender, race, and educational level

Uncategorized Nov 10, 2022


Every year, fungi cause millions of deaths and tens of millions of infections around the world. In immunocompromised patients, fungi are mostly opportunistic, causing moderate to severe illness. Fungal infections are also linked to higher illness rates and high healthcare costs. The risk of serious fungal infection is decreasing, largely due to a reduction in HIV-associated infections. However, patients with certain underlying conditions are increasingly being affected by infections.

The effects of race, ethnicity and socioeconomic status on fungal infections and associated patient outcomes have increased in healthcare settings. Previous research has shown a link between health disparities and fungal infections.

This research looked at the demographic and socio-economic factors connected with fungal infection risk in the United States up to 2019. The researchers used hospital discharge data from the Agency for Healthcare Research and Quality's National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), and Healthcare Cost and Utilization Project (HCUP). NIS is the largest database of US hospitalization data, covering more than 96% of the population. Hospitalizations are included in HCUP data rather than individual patients.


To identify at-risk patients and invasive and noninvasive fungal infections, codes from the International Classification of Diseases, 10th Revision (ICD-10) were used. Patient records provided information on sex, race, and ethnicity. Every year-end income quartile (Q) is predefined in the HCUP dataset using an estimate of the median household income in US dollars of residents living within a patient's postal code.
The scientists then classified age groups as pediatric (0-17 years of age), adult (18-64 years of age), and elderly (>65 years of age). They defined urban-rural status as previously described (22), and counties with more than 50,000 people were considered urban. Male patients were 1.5-3.5 times more likely than female patients to have invasive fungal infections diagnosed. Cryptococcosis, pneumocystosis, and coccidioidomycosis were 1.4-5.9 times more common in black, Hispanic, and Native American patients.


  • Invasive fungal infections were diagnosed more frequently in male patients, at 1.4-3.4 times the rate for female patients. We observed the greatest differences between male and female patients in coccidioidomycosis, pneumocystosis, and cryptococcosis.
  • Noninvasive candidiasis, including vulvovaginal candidiasis, was the only diagnosis made more frequently in female patients.
  • Male patients had >1 fungal-associated risk condition diagnosed at 1.2 times the rate for female patients. Of 19 risk conditions we analyzed, 16 were diagnosed more frequently in male patients.


  • Risk conditions and fungal infections were diagnosed among racial and ethnic subgroups at levels that were generally consistent with the current racial and ethnic composition of the United States. We noticed some deviations that highlight racial and ethnic health disparities.
  • In Asian American and Pacific Islander (AA/PI) patients, the overall rate of fungal infection diagnosis was reduced. AA/PI patients had higher rates of aspergillosis (RR 1.4, 95 percent CI 1.3-1.5), coccidioidomycosis (RR 2.5, 95 percent CI 2.5-2.9), and mucormycosis (RR 1.9, 95 percent CI 1.5-2.5).
  • Native American patients had a 5.9-fold higher rate of coccidioidomycosis (95 percent CI 5.2-6.6) than non-Hispanic White patients. Native American patients had higher rates of cryptococcosis (RR 2.5, 95 percent CI 1.9-3.3) than non-Hispanic White patients.


  • In 2019, nearly one-third of the 35.5 million hospitalizations were linked to living in lower-income areas. Fungal infections were more common in hospitalizations billed to Medicaid than in those billed to private insurance. Medicare had higher rates for 16 of the 19 risk conditions that the researchers looked into.
  • Self-pay hospitalizations are for patients who are uninsured or underinsured. In hospitalizations billed as self-pay, rates of HIV (RR 3.1, 95 percent CI 3.0-3.2) and tuberculosis (RR 2.4, 95 percent CI 2.1-2.8) were higher.


  • Older/Senior patients had a fungus infection diagnosis rate that was 1.3 times higher than adult patients (95 percent CI 1.3-1.3). Coccidioidomycosis was a fungus that was less frequently seen in elderly people than in adults.
  • Pediatric patients accounted for just 4.2% of diagnosed fungal infections in 2019, despite accounting for 14.9% of hospitalisations in 2019. At 0.2 times the rate of adult patients, pediatric patients had >1 fungal-associated risk condition diagnosed.


  • Several fungal infections were more frequently diagnosed in patients from urban areas. Candidiasis and histoplasmosis were the infections most frequently diagnosed in rural patients.
  • Urban patients had significantly higher rates of HIV (RR 2.9, 95 percent CI 2.9-2.9) and tuberculosis (RR 2.0, 95 percent CI 1.8-2.3) than rural patients. Asthma (RR 1.4, 95 percent CI 1.4-1.4) and transplants (RR 1.2, 95 percent CI 1.2-1.2) were also more common among urban patients.


We looked at the rates of fungal infection diagnoses in hospitalizations based on race and ethnicity, as well as socioeconomic status.

  • Male patients had a 1.4-3.5 times higher rate of invasive fungal infection diagnoses in HCUP NIS than female patients. The link between sex and susceptibility is more complicated.
  • Non-Hispanic White and AA/PI patients had higher rates of aspergillosis than other racial and ethnic groups. Higher-income individuals are more likely to be diagnosed with aspergillosis.
  • Candidiasis was more frequently diagnosed in Black individuals. Male patients had a higher rate of invasive candidiasis. Female patients had a higher rate of noninvasive candidiasis.
  • Coccidioidomycosis is endemic in the US Southwest, and histoplasmosis is prevalent in the Ohio and Mississippi River Valley regions. In coccidioidomycosis, environmental exposure is critical; workers who do soil-disturbing work or are exposed to dusty conditions are at greater risk.
  • Non-Hispanic White patients had up to three times the risk of histoplasmosis as other racial and ethnic groups. Adult, low-income, and rural patients had higher diagnoses of histoplasmosis.
  • Cryptococcosis and pneumocystosis have historically been linked to HIV. We discovered that Black and Hispanic patients had a 2-3 times higher rate of cryptococcosis and pneumocystosis diagnosis than non-Hispanic White patients.
  • Mucormycosis is a rare and often fatal illness. AA/PI and Hispanic patients had higher diagnoses.
  • Fungal infections are most commonly superficial cutaneous and mucosal. Seniors had a higher incidence of unspecified mycotic infections.

The findings are interesting from the USA, but the data may understate the true burden of fungal illness in the United States and in other countries like Australia. Many ICD-10 codes for fungal infections are unclear in terms of their sensitivity and specificity, so misclassification is possible.

In conclusion, this research presents a comprehensive overview of fungal infections and associated risk factors among hospitalized patients. The findings show that demographic and socioeconomic factors influence differences in fungus infection diagnosis rates.


Rayens E, Rayens MK, Norris KA. Demographic and Socioeconomic Factors Associated with Fungal Infection Risk, United States, 2019. Emerg Infect Dis. 2022 Oct;28(10):1955–69. doi: 10.3201/eid2810.220391. PMID: 36149028; PMCID: PMC9514344.



50% Complete

Get your FREE mould assessment questionnaire

Find out today how your home ranks using our 12-point rating scale and take control of your environmental health.