Coccidioidomycosis Among American Indians and Alaska Natives, 2001-2014

Abstract

Background: American Indians and Alaska Natives (AI/ANs) may be uniquely vulnerable to coccidioidomycosis given the large population residing in the Southwestern United States. We describe coccidioidomycosis-associated hospitalizations and outpatient visits during 2001-2014 in the Indian Health Service (IHS) system and compare hospitalizations with data from the Agency for Healthcare Research and Quality's National (Nationwide) Inpatient Sample (NIS).

Methods: We identified hospitalizations in the IHS and the NIS and outpatient visits in the IHS using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes 114.0-114.9. We calculated average annual hospitalization and outpatient visit rates per 1 000 000 population and used Poisson regression to calculate rate ratios (RRs) and 95% confidence intervals (CIs). We used multivariable logistic regression to assess factors associated with IHS hospitalization.

Results: AI/ANs had the highest average annual hospitalization rate (58.0; 95% CI, 49.5-66.6) of any racial/ethnic group in the NIS, compared with 13.4 (95% CI, 12.7-14.2) for non-Hispanic whites. IHS data showed a hospitalization rate of 37.0; the median length of stay (interquartile range) was 6 (3-10) days. The average annual outpatient visit rate in IHS was 764.2, and it increased from 529.9 in 2001 to 845.9 in 2014. Male sex, age ≥65 years, diabetes, and extrapulmonary or progressive coccidioidomycosis were independently associated with increased risk for hospitalization. Twenty-four percent of patients had ICD-9-CM codes for community-acquired pneumonia in the 3 months before coccidioidomycosis diagnosis.

Conclusions: AI/ANs experience high coccidioidomycosis-associated hospitalization rates, high morbidity, and possible missed opportunities for earlier diagnosis. Yearly trends in IHS data were similar to the general increase in hospitalizations and reported cases nationwide in the same period.

Keywords: Alaska Natives; Indians; North American; United States; coccidioidomycosis; hospitalization; outpatients.

Figure 1.

A, Trends in rates of coccidioidomycosis-associated inpatient visits among American Indian/Alaska Natives (Indian Health Service), 2001–2014. B, Trends in rates of coccidioidomycosis-associated outpatient visits among American Indian/Alaska Natives (Indian Health Service), 2001–2014. (Data are not shown for rates with <20 hospitalizations.)