Vulvovaginal Candidiasis Among American Indian and Alaska Native People, Indian Health Service, 2016-2022

Abstract

Vulvovaginal candidiasis (VVC) is an infection caused by the yeast Candida that affects more than 50% of women in their lifetime. We aimed to describe VVC among American Indian/Alaska Native (AI/AN) girls and women who were receiving care in the Indian Health Service (IHS) system during 2016-2022. We calculated the annual VVC prevalence per 1000 IHS user population and examined underlying medical conditions, previous diagnoses, and antifungal treatment. Among 6 million female patient-years, 70 766 patients had ≥1 VVC diagnosis code (2022 prevalence: 14.2 per 1000 IHS user population). Frequent previous or concurrent diagnoses included diabetes (24.8%), urinary tract infection (13.6%), screening for sexually transmitted infection (13.2%), and unspecified acute vaginitis or vulvitis (13.0%). Approximately one-third (33.1%) of patients received fluconazole, and 25.7% received prescription topical antifungal medication. VVC was a common condition among AI/AN patients who accessed care in the IHS health care system. VVC prevalence among AI/AN patients was similar to the prevalence among the broader US population. These data provide a baseline for future studies to evaluate diagnostic and treatment practices for VVC among AI/AN people.

Vulvovaginal candidiasis (VVC) is a common gynecologic condition that affects more than 50% of women in their lifetime. ¹ VVC symptoms (eg, vaginal discharge, pruritus, pain) resemble those of other causes of vaginitis, yet patients frequently do not receive the recommended diagnostic testing, often resulting in inappropriate empiric treatment.^2,3 VVC can usually be treated with a short course of oral antifungal medication (typically fluconazole) or with over-the-counter or prescription topical antifungal medication, although severe or recurrent cases may be more difficult to treat and require longer treatment courses.

American Indian/Alaska Native (AI/AN) people are disproportionately affected by certain fungal diseases.^4,5 However, to our knowledge, whether this disparity exists for VVC has not been explored. A better understanding of VVC in this population may help provide insight into clinical practices, which have implications for patient outcomes and antimicrobial stewardship. Therefore, we sought to estimate the prevalence of VVC and describe the features of patients with VVC by using Indian Health Service (IHS) medical records.

Methods

We examined IHS National Patient Information Reporting System (NPIRS) data to identify female patients who received an International Classification of Diseases, Tenth Revision, Clinical Modification ⁶ diagnosis code for VVC during 2016-2022. NPIRS data include hospitalization, outpatient visit, and prescription records for IHS beneficiaries who receive care at IHS-funded federal or tribally operated health care facilities or contracted care.

We calculated annual, age-specific, and region-specific VVC prevalence per 1000 IHS user population. User population was defined as the annual number of AI/AN people who had a health care encounter in the IHS-funded health system during the 3 preceding years. IHS administrative regions were categorized as Alaska, East (Nashville), Northern Plains East (Bemidji), Northern Plains West (Billings, Great Plains), Southern Plains (Oklahoma City), Southwest (Albuquerque, Navajo, Phoenix, Tucson), and West (California, Portland). For patients with VVC in 2022, we examined the frequency of selected medical conditions and VVC-related symptoms (Supplemental Table) on or in the 30 days before, antifungal medication on or in the 7 days after, and number of return visits for VVC in the year after patients’ first VVC diagnosis code. This activity was reviewed by the Centers for Disease Control and Prevention (CDC), deemed not research, and conducted consistent with applicable federal law and CDC policy. (See eg, 45 CFR part 46, 21 CFR part 56; 42 USC §241[d]; 5 USC §552a; 44 USC §3501 et seq.)

Results

Among >6 million female patient-years during 2016-2022, 70 766 patients had ≥1 VVC diagnosis code. The median (IQR) age was 36 (25-51) years. The annual prevalence of VVC decreased from 17.9 per 1000 IHS user population in 2016 to 14.2 per 1000 IHS user population in 2022; the decrease primarily occurred during 2019-2020 and was relatively similar across age groups (Supplemental Figure) and regions (data not shown). The VVC prevalence per 1000 IHS user population in 2022 was highest among patients aged 19 to 44 years (20.1) and among patients in Alaska (24.6), followed by the Southwest region (15.1) (Table).

Table.

Number and prevalence of female patients with vulvovaginal candidiasis (VVC), selected conditions, and VVC-related symptoms among American Indian/Alaska Native people in Indian Health Service data, 2022

Characteristic	No. (column %)	User population	Rate per 1000 IHS user population
Total	12 087 (100.0)	853 795	14.2
Age, y
<1	21 (0.2)	6727	3.1
1-18	745 (6.2)	232 202	3.2
19-44	6541 (54.1)	326 266	20.0
45-64	3431 (28.4)	181 806	18.9
≥65	1349 (11.2)	106 770	12.6
IHS region a
Alaska	1970 (16.3)	80 232	24.6
East	389 (3.2)	30 218	12.9
Northern Plains East	518 (4.3)	51 853	10.0
Northern Plains West	1465 (12.1)	103 337	14.2
Southern Plains	2710 (22.4)	213 801	12.7
Southwest	4118 (34.1)	272 162	15.1
West	917 (7.6)	102 192	9.0
Symptoms and conditions on or in the 30 days before VVC diagnosis code		—	—
Diabetes	2996 (24.8)	—	—
Urinary tract infection or acute cystitis	1646 (13.6)	—	—
Screening for sexually transmitted infection	1591 (13.2)	—	—
Acute vaginitis or vulvitis	1574 (13.0)	—	—
Leukorrhea	1260 (10.4)	—	—
Dysuria	1150 (9.5)	—	—
Routine gynecological examination	860 (7.1)	—	—
Pregnancy	728 (6.0)	—	—
Urinary frequency	229 (1.9)	—	—
Contact with and suspected exposure to sexually transmitted infection	144 (1.2)	—	—
Trichomoniasis	141 (1.2)	—	—
Pruritus vulvae	103 (0.9)	—	—
Screening for other infections	101 (0.8)	—	—
Gonorrhea	44 (0.4)	—	—
Chlamydia	41 (0)	—	—
HIV	7 (0)	—	—

Abbreviations: —, not applicable; IHS, Indian Health Service.

^aAlaska, East (Nashville), Northern Plains East (Bemidji), Northern Plains West (Billings, Great Plains), Southern Plains (Oklahoma City), Southwest (Albuquerque, Navajo, Phoenix, Tucson), and West (California, Portland).

For patients with VVC in 2022, the most frequent diagnosis codes that we examined were diabetes (24.8%), urinary tract infection (13.6%), screening for sexually transmitted infection (13.2%), and unspecified acute vaginitis or vulvitis (13.0%) (Table). Approximately one-third (33.1%) of patients received fluconazole, and 25.7% received prescription topical antifungal medication, most frequently clotrimazole (20.0%), followed by nystatin (6.6%). In total, 14% of patients had 1 additional visit for VVC within 1 year, 3% had 2 visits, and 1% had ≥3 visits.

Discussion

VVC was a common condition among AI/AN people who received health care in IHS. The annual prevalence of VVC during 2016-2022 was comparable with that of a large commercially insured patient population during 2018 (14 per 1000 population). ² The similarity between the prevalence of VVC among AI/AN people in our study and the general population is also consistent with a national survey that showed no difference in VVC rates between White people and non-White people. ¹

The higher VVC prevalence in Alaska and the Southwest found in our study contrasts with previous work, indicating that VVC is most common in the South among the general population. ² This finding may be related to greater completeness of the reporting network in the Alaska (where access to health care outside of IHS might be limited) and the Southwest regions compared with other regions. Regional differences in VVC rates could also be due to variation in health care–seeking behaviors. ⁷ For example, AI/AN women who live in remote areas may have limited options for over-the-counter treatment and, therefore, may be more likely than AI/AN women who live in nonremote areas to seek health care for VVC. The decrease in VVC rates during 2019-2020 is likely related to reduced health care–seeking behavior during the COVID-19 pandemic. ⁸

Our analysis found that one-quarter of patients had diabetes, which is a major risk factor for VVC and disproportionately affects AI/AN people.^1,9 Diagnoses of gynecologic conditions such as urinary tract infections, unspecified vaginitis, and sexually transmitted infections in the month before VVC suggest possible misdiagnosis or diagnostic uncertainty, consistent with previous findings. ² The proportion of patients prescribed fluconazole (33%) in this analysis was lower than in a study of commercially insured patients with VVC (70%), whereas the proportion prescribed topical antifungal medication was higher (26% vs 19%). ² One limitation of this analysis was that the dataset did not include information about the use of over-the-counter antifungal medication, which patients with VVC frequently (>40%) reported using in a national survey. ¹ Another limitation was the lack of information about point-of-care and laboratory diagnostic testing, including Candida species identification and antifungal susceptibility testing.

Public Health Implications

These results provide baseline data for monitoring the epidemiology of VVC among AI/AN people. Further investigation can help evaluate diagnostic and treatment practices for VVC among this population and identify potential opportunities for improvement.